Why is my object staying null? - java

For some reason, I can't seem to fix this giving me a NullPointerException. I print out poly.term.degree without any errors, and then set poly.next equal to poly and then get a nullPointerException when I try to print out poly.next.term.degree which should seemingly be the same. I'm aware this is incomplete code but I think this is my main issue.
public Polynomial add(Polynomial p)
{
Polynomial newPoly = new Polynomial();
newPoly.poly = new Node(0,0,null);
Polynomial myCurr = this;
Polynomial otherCurr = p;
while(myCurr.poly != null)
{
int myDeg = myCurr.poly.term.degree;
int otherDeg = p.poly.term.degree;
float myCo = myCurr.poly.term.coeff;
float otherCo = otherCurr.poly.term.coeff;
if(myDeg == otherDeg)
{
System.out.println("degrees "+myDeg + " and "+ otherDeg+ " are equal, creating new node...");
Node n = new Node(myCo+otherCo,p.poly.term.degree, newPoly.poly.next);
System.out.println(newPoly.poly.term.degree);
newPoly.poly.next = newPoly.poly;
newPoly.poly = n;
System.out.println(newPoly.poly.next.term.degree); // Gives me a NullPointerException
}
Also, the constructors and everything for these classes is below.
package poly;
import java.io.*;
import java.util.StringTokenizer;
/**
* This class implements a term of a polynomial.
*
* #author runb-cs112
*
*/
class Term {
/**
* Coefficient of term.
*/
public float coeff;
/**
* Degree of term.
*/
public int degree;
/**
* Initializes an instance with given coefficient and degree.
*
* #param coeff Coefficient
* #param degree Degree
*/
public Term(float coeff, int degree) {
this.coeff = coeff;
this.degree = degree;
}
/* (non-Javadoc)
* #see java.lang.Object#equals(java.lang.Object)
*/
public boolean equals(Object other) {
return other != null &&
other instanceof Term &&
coeff == ((Term)other).coeff &&
degree == ((Term)other).degree;
}
/* (non-Javadoc)
* #see java.lang.Object#toString()
*/
public String toString() {
if (degree == 0) {
return coeff + "";
} else if (degree == 1) {
return coeff + "x";
} else {
return coeff + "x^" + degree;
}
}
}
/**
* This class implements a linked list node that contains a Term instance.
*
* #author runb-cs112
*
*/
class Node {
/**
* Term instance.
*/
Term term;
/**
* Next node in linked list.
*/
Node next;
/**
* Initializes this node with a term with given coefficient and degree,
* pointing to the given next node.
*
* #param coeff Coefficient of term
* #param degree Degree of term
* #param next Next node
*/
public Node(float coeff, int degree, Node next) {
term = new Term(coeff, degree);
this.next = next;
}
}
/**
* This class implements a polynomial.
*
* #author runb-cs112
*
*/
public class Polynomial {
/**
* Pointer to the front of the linked list that stores the polynomial.
*/
Node poly;
/**
* Initializes this polynomial to empty, i.e. there are no terms.
*
*/
public Polynomial() {
poly = null;
}
/**
* Reads a polynomial from an input stream (file or keyboard). The storage format
* of the polynomial is:
* <pre>
* <coeff> <degree>
* <coeff> <degree>
* ...
* <coeff> <degree>
* </pre>
* with the guarantee that degrees will be in descending order. For example:
* <pre>
* 4 5
* -2 3
* 2 1
* 3 0
* </pre>
* which represents the polynomial:
* <pre>
* 4*x^5 - 2*x^3 + 2*x + 3
* </pre>
*
* #param br BufferedReader from which a polynomial is to be read
* #throws IOException If there is any input error in reading the polynomial
*/
public Polynomial(BufferedReader br) throws IOException {
String line;
StringTokenizer tokenizer;
float coeff;
int degree;
poly = null;
while ((line = br.readLine()) != null) {
tokenizer = new StringTokenizer(line);
coeff = Float.parseFloat(tokenizer.nextToken());
degree = Integer.parseInt(tokenizer.nextToken());
poly = new Node(coeff, degree, poly);
}
}

I think the problem lies here:
newPoly.poly.next = newPoly.poly;
newPoly.poly = n;
At first you say, that newPoly.poly.next = newPoly.poly; so you assign the current element to the next, which is recursive. And then you say newPoly.poly = n; . So you assign a new element to newPoly. I think that the garbage collector deletes the newPoly element, because it is overwritten, so you lose the reference to the newPoly element. Which means when you access it later you get a nullpointer exception. You could fix this like this:
newPoly.poly.next = n;
//and dont forget to set the next pointer of the new elemnt to 0
n.next = NULL;
Just assign the new element to the next element.
EDIT
#hendersawn
You could sort the list. See below:
sort(Node head_p){ //do not change the head, or you will lose the beginning.
Node tmp_p;
Node curr_p = head_p;
while(curr_p != NULL){
if(curr_p.poly.term.degree < curr_p.next.poly.term.degree) //either degree is smaller or greater
{//swap
tmp_p = curr_p; //save first element
curr_p = curr_p.next; //set first element to second
//now the 2 element is the actual third element so we need
//to put the first between the second and the third
tmp_p.next = curr_p.next; //set next of first to third
curr_p.next = tmp_p; //set second element to the first that we saved before
}
curr_p = curr_p.next; //move to next element...rinse repeat
}
}

newPoly might be null
newPoly.poly might be null
newPoly.poly.next might be null
newPoly.poly.next.term might be null
or
newPoly.poly.next.term.degree might be null.
To avoid NullPointerException, you need to make sure that any member used is initialized with a proper value.

Nothing is obviously null that I can tell, however with four 'dots' (something.something.something.something) of Object Oriented Indirection, you're going to encounter this problem a lot. Usually two - three 'dots' on a single line are all you should ever do, but since that's more about the design and not the error, I digress.
The way to find this problem would be to either:
Put a breakpoint right at that line and see what the variables are there, and which one is null or
Do a System.out.println for each of the components to see which one breaks it, and work backwards from there. ex:
System.out.println(newPoly.poly.next.term.degree); // Gives me a NullPointerException
System.out.println(newPoly);
System.out.println(newPoly.poly);
System.out.println(newPoly.poly.next);
System.out.println(newPoly.poly.next.term);
because the nullPointerException would only get thrown on one of those (it can't be degree, otherwise that statement would have just printed 'null'
if I had to bet, I'd say it's probably newPoly.poly.next which is null
the lines:
newPoly.poly.next = newPoly.poly;
newPoly.poly = n;
Superficially seem like they would be the culprit of your trouble, since you're assigning the 'next' of your newPoly.poly, but then you re-assign your newPoly.poly, and lose that old reference to .next, I think.
Good luck! hope that helps.

Related

JAVA Evaluating postfix expressions -- unable to throw empty or invalid expressions

I'm writing a program that will evaluate a postfix expression and print both the original expression and the result. But I want to account for the validity of the expression as well. For this, I've written two exception classes -- one for an empty collection and one for invalid postfix expressions. But my code is getting stuck somewhere; my output evaluates the first expression correctly, but then only prints the original postfix expressions after that. I believe the problem is perhaps coming from my PostfixEvaluator class (see below), where I attempt to check for the size of my stack in the evaluate method. When commented out, my postfix expressions evaluate (albeit without the exceptions being caught, but still, it's something).
My code and resulting output:
Postfix Tester:
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
public class PostfixTester
{
/**
* Reads and evaluates multiple postfix expressions.
* #throws FileNotFoundException
*/
public static void main(String[] args) throws FileNotFoundException{
String expression, again;
int result;
//Scanner in = new Scanner(System.in);
Scanner in = new Scanner(new File("test.txt"));
PostfixEvaluator evaluator = new PostfixEvaluator();
while(in.hasNext()){
expression = in.nextLine();
System.out.println(expression);
try{
result = evaluator.evaluate(expression);
System.out.println("The result is: " + result);
}
catch(EmptyCollectionException e){
e.getMessage();
}
catch(InvalidPostfixExpressionException e){
e.getMessage();
}
System.out.println();
}
}
}
Postfix Evaluator:
import java.util.Stack;
import java.util.Scanner;
public class PostfixEvaluator
{
private final static char ADD = '+';
private final static char SUBTRACT = '-';
private final static char MULTIPLY = '*';
private final static char DIVIDE = '/';
private ArrayStack<Integer> stack;
/**
* Sets up this evalutor by creating a new stack.
*/
public PostfixEvaluator()
{
stack = new ArrayStack<Integer>();
}
/**
* Evaluates the specified postfix expression. If an operand is
* encountered, it is pushed onto the stack. If an operator is
* encountered, two operands are popped, the operation is
* evaluated, and the result is pushed onto the stack.
* #param expr string representation of a postfix expression
* #return value of the given expression
*/
public int evaluate(String expr)
{
int op1, op2, result = 0;
String token;
Scanner parser = new Scanner(expr);
while (parser.hasNext())
{
token = parser.next();
if (isOperator(token))
{
op2 = (stack.pop()).intValue();
op1 = (stack.pop()).intValue();
result = evaluateSingleOperator(token.charAt(0), op1, op2);
stack.push(new Integer(result));
}
else
stack.push(new Integer(Integer.parseInt(token)));
}
if(stack.size() != 1){
throw new InvalidPostfixExpressionException();
}
return result;
}
/**
* Determines if the specified token is an operator.
* #param token the token to be evaluated
* #return true if token is operator
*/
private boolean isOperator(String token)
{
return ( token.equals("+") || token.equals("-") ||
token.equals("*") || token.equals("/") );
}
/**
* Peforms integer evaluation on a single expression consisting of
* the specified operator and operands.
* #param operation operation to be performed
* #param op1 the first operand
* #param op2 the second operand
* #return value of the expression
*/
private int evaluateSingleOperator(char operation, int op1, int op2)
{
int result = 0;
switch (operation)
{
case ADD:
result = op1 + op2;
break;
case SUBTRACT:
result = op1 - op2;
break;
case MULTIPLY:
result = op1 * op2;
break;
case DIVIDE:
result = op1 / op2;
}
return result;
}
}
My ArrayStack class:
import java.util.Arrays;
public class ArrayStack<T> implements StackADT<T>
{
private final static int DEFAULT_CAPACITY = 100;
private int top;
private T[] stack;
/**
* Creates an empty stack using the default capacity.
*/
public ArrayStack()
{
this(DEFAULT_CAPACITY);
}
/**
* Creates an empty stack using the specified capacity.
* #param initialCapacity the initial size of the array
*/
public ArrayStack(int initialCapacity)
{
top = 0;
stack = (T[])(new Object[initialCapacity]);
}
/**
* Adds the specified element to the top of this stack, expanding
* the capacity of the array if necessary.
* #param element generic element to be pushed onto stack
*/
public void push(T element)
{
if (size() == stack.length)
expandCapacity();
stack[top] = element;
top++;
}
/**
* Creates a new array to store the contents of this stack with
* twice the capacity of the old one.
*/
private void expandCapacity()
{
stack = Arrays.copyOf(stack, stack.length * 2);
}
/**
* Removes the element at the top of this stack and returns a
* reference to it.
* #return element removed from top of stack
* #throws EmptyCollectionException if stack is empty
*/
public T pop() throws EmptyCollectionException
{
if (isEmpty())
throw new EmptyCollectionException("stack");
top--;
T result = stack[top];
stack[top] = null;
return result;
}
/**
* Returns a reference to the element at the top of this stack.
* The element is not removed from the stack.
* #return element on top of stack
* #throws EmptyCollectionException if stack is empty
*/
public T peek() throws EmptyCollectionException
{
if (isEmpty())
throw new EmptyCollectionException("stack");
return stack[top-1];
}
/**
* Returns true if this stack is empty and false otherwise.
* #return true if this stack is empty
*/
public boolean isEmpty()
{
// To be completed as a Programming Project
return top==0;
}
/**
* Returns the number of elements in this stack.
* #return the number of elements in the stack
*/
public int size()
{
// To be completed as a Programming Project
return top;
}
/**
* Returns a string representation of this stack.
* #return a string representation of the stack
*/
public String toString()
{
return stack.toString();
}
}
My input file of expressions (for testing purposes, the final two should throw the two exceptions):
8 4 + 3 *
7 5 2 * +
3 1 + 4 2 - *
5 8 2 - +
5 8 - +
6 3 2 -
My actual output:
8 4 + 3 *
The result is: 36
7 5 2 * +
3 1 + 4 2 - *
5 8 2 - +
5 8 - +
6 3 2 -
Obviously, I was expecting the first four expressions to follow as the first one did, and the final two to display my exception messages, but I can't seem to figure out where I've gone wrong.
You push the result to the evaluator stack.
You reuse the evaluator in the tester.
The evaluator is not clean when you start the second iteration in tester (the result of the previous expression is in the stack).
The easiest (and the correct) way to fix this is to change "return result;" to "return stack.pop();"
Next time use a debugger and step through your failing code. It's one of the most useful skills you can have in programming.
Asserting preconditions would help too. Check that stack is empty when you start evaluating an expression.
The exceptions are thrown but since class PostfixTester is using e.getMessgage(), you won't see the error in the output.
You should use, System.out.println(e.getMessage()) in order to print message. But even this change will print null.
You need to catch exceptions in PostfixEvaluator.evaluate() method and throw again with the message.

Checking With Assertion

The methods setDates and setTimes have as preconditions that none of their arguments are null. This is to be checked by means of an assertion. (This means that if the precondition is not met, the program will fail at the assertion, and an AssertionError will be thrown.)
here is my code:
public class Section
{
/**
* Default section number.
*/
private static final String DEFAULT_SECTION_NUMBER = "";
/**
* Constant for building Strings with newline characters within them.
*/
private static final String LINE_SEPARATOR = System.
getProperty("line.separator");
/**
* The maximum number of students permitted into a section.
*/
private static final int MAXIMUM_STUDENTS_PER_SECTION = 30;
/**
* Valid length for a sectionNumber string.
*/
private static final int SECTION_NUMBER_LENGTH = 3;
/**
* Shared variable for keeping count of the number of section objects in
* existence.
*/
private static int count = 0;
/**
* The date at which the section is finished.
*/
private Date endDate;
/**
* The end time for the meeting of the section.
*/
private Time2 endTime;
/**
* The list of students in the class. This declaration uses the Java 7 facility
* of not repeating the generic type if that type can be inferred by the
* compiler.
*/
private final List<Student> roster = new ArrayList<>();
/**
* The three-character designation of the section (called a
* “number”).
*/
private String sectionNumber = DEFAULT_SECTION_NUMBER;
/**
* The date on which the section starts to meet.
*/
private Date startDate;
/**
* The time of day at which the section meets.
*/
private Time2 startTime;
/**
* The course of which this is a section.
*/
private final Course thisCourse;
/**
* Constructor.
*
* #param course the course of which this is a section
* #param sectionNumber the section number (within the course) of this section
* #throws SectionException
*/
public Section(Course course, String sectionNumber) throws SectionException
{
/* Increment the collective count of all Section objects that have been
created. Do this first as the object already exists. */
++count;
this.thisCourse = course;
try
{
if( isValidSectionNumber(sectionNumber) )
this.sectionNumber = sectionNumber;
}
catch (Exception ex)
{
throw new SectionException("Error in constructor", ex);
}
}
/**
* Add a student to the course.
*
* #param student the student object to be added. If the course is full, the
* student is not added
*/
public void addStudent(Student student)
{
if( roster.size() != MAXIMUM_STUDENTS_PER_SECTION )
roster.add(student);
}
/**
* Get details about the current state of this section, including the course of
* which it is part, the dates it starts and ends, times, etc., and the current
* count of the enrollment.
*
* #return the section details
*/
public String getDetails()
{
return String.join(LINE_SEPARATOR,
"Section: " + this.toString(),
"Course: " + thisCourse.getDetails(),
"Dates: " + startDate + " to " + endDate,
"Times: " + startTime + " to " + endTime,
"Enrollment: " + roster.size());
}
/**
* Create a string that represents the information about the students in the
* course.
*
* #return a string that represents the information about the students in the
* course
*/
public String getRoster()
{
/* The following commented-out code is the obvious way to do this, using
String concatenation (and this is acceptable). However, the recommended
Java approach to this kind of operation is to use a StringJoiner (new
class in Java 8), as this uses less garbage collection resources. */
// String result = "";
// for( Student student : roster )
// {
// result += ( result.isEmpty() ? "" : LINE_SEPARATOR) + student;
// }
// return result;
StringJoiner stringJoiner = new StringJoiner(LINE_SEPARATOR);
for( Student student : roster )
stringJoiner.add(student.toString());
return stringJoiner.toString();
}
/**
* Get a count of the number of students registered (on the roster) for this course.
*
* #return a count of the number of students registered for this course
*/
public int getRosterCount()
{
return roster.size();
}
/**
* Get the section number for this course.
*
* #return the section number for this course
*/
public String getSectionNumber()
{
return sectionNumber;
}
/**
* Set the start and end dates for the section.
*
* #param startDate the start date
* #param endDate the end date
*/
public void setDates(Date startDate, Date endDate)
{
/* There is no requirement to validate these. */
this.startDate = startDate;
this.endDate = endDate;
}
/**
* Set the start time and the end time for the meetings of the section.
*
* #param startTime the start time for meetings of the section
* #param endTime the end time for the meetings of the section
*/
public void setTimes(Time2 startTime, Time2 endTime)
{
/* There is no requirement to validate these. */
this.startTime = startTime;
this.endTime = endTime;
}
/**
* Section number (prefixed)
*
* #return Section number (prefixed)
*/
#Override
public String toString()
{
return thisCourse.toString() + "-" + sectionNumber;
}
/**
* Finalization. Reduce the instance count by 1.
*
* #throws Throwable standard interface.
*/
#SuppressWarnings("FinalizeDeclaration")
#Override
protected void finalize() throws Throwable
{
/* Decrement the count of the collective total of all Section objects. */
--count;
super.finalize();
}
/**
* Get a count of how many total Section objects are currently in existence.
*
* #return a count of how many Section objects are currently in existence
*/
public static int getSectionCount()
{
return count;
}
/**
* Validate the sectionNumber string. It must be of the correct length.
*
* #param sectionNumber the sectionNumber string
* #return true if the string if valid, otherwise false
*/
private static boolean isValidSectionNumber(String sectionNumber)
{
return sectionNumber != null &&
sectionNumber.length() == SECTION_NUMBER_LENGTH;
}
}
would i simply place 'assert' before this.startDate = startDate; and so forth??? my book only has one example and it is for ensuring a value is between 0 and 10.
this is the example my book uses:
public class AssertTest
{
public static void main(string[] args)
{
Scanner input = new Scanner(System.in);
System.out.print("Enter a number between 0 and 10: ");
int number = input.nextInt();
//assert that the value is >= 0 and <= 10
assert (number >= 0 && number <= 10) : "bad number: " + number;
System.out.printf("You entered %d%n", number);
}
}
so could i say
assert this.startDate = startDate
assert this.endDate = endDate
and so on?
First of all the methods setTime and setDates are public what suggests that they may be used outside of the package. Given that you have no control over parameters - using assert would not be considered as the best practice. You should rather use Runtime Exceptions such as IllegalArgumentException when value can be supplied externally (and you have no control over it):
if (startDate == null || endDate == null)
throw new IllegalArgumentException("Non-null arguments are required");
The syntax for the Assert would be as follows:
assert startDate != null;
assert endDate != null;
You can also use the following syntax in order to output additional information when assertion fails:
assert startDate != null : "startDate was set to null"
assert endDate != null : "endDate was set to null"

can't find source of inadvertent loop

I started refactoring this program I was working on and hit a major road block... I have one class that acts as a nucleus, with about 6 other smaller (but still important) classes working together to run the program... I took one method [called 'populate()'] out the nucleus class and made an entirely new class with it [called 'PopulationGenerator'], but when I try to create an object of the newly created class anywhere in the nucleus class I get stuck in a never ending loop of that new class
I've never had this issue when trying to create objects before... Here's the nucleus class before refactoring:
public class Simulator
{
// Constants representing configuration information for the simulation.
// The default width for the grid.
private static final int DEFAULT_WIDTH = 120;
// The default depth of the grid.
private static final int DEFAULT_DEPTH = 80;
// The probability that a fox will be created in any given grid position.
private static final double FOX_CREATION_PROBABILITY = 0.02;
// The probability that a rabbit will be created in any given grid position.
private static final double RABBIT_CREATION_PROBABILITY = 0.08;
// List of animals in the field.
private List<Animal> animals;
// The current state of the field.
private Field field;
// The current step of the simulation.
private int step;
// A graphical view of the simulation.
private SimulatorView view;
/**
* Construct a simulation field with default size.
*/
public Simulator()
{
this(DEFAULT_DEPTH, DEFAULT_WIDTH);
}
/**
* Create a simulation field with the given size.
* #param depth Depth of the field. Must be greater than zero.
* #param width Width of the field. Must be greater than zero.
*/
public Simulator(int depth, int width)
{
if(width <= 0 || depth <= 0) {
System.out.println("The dimensions must be greater than zero.");
System.out.println("Using default values.");
depth = DEFAULT_DEPTH;
width = DEFAULT_WIDTH;
}
animals = new ArrayList<Animal>();
field = new Field(depth, width);
// Create a view of the state of each location in the field.
view = new SimulatorView(depth, width);
view.setColor(Rabbit.class, Color.orange);
view.setColor(Fox.class, Color.blue);
// Setup a valid starting point.
reset();
}
/**
* Run the simulation from its current state for a reasonably long period,
* (4000 steps).
*/
public void runLongSimulation()
{
simulate(4000);
}
/**
* Run the simulation from its current state for the given number of steps.
* Stop before the given number of steps if it ceases to be viable.
* #param numSteps The number of steps to run for.
*/
public void simulate(int numSteps)
{
for(int step = 1; step <= numSteps && view.isViable(field); step++) {
simulateOneStep();
}
}
/**
* Run the simulation from its current state for a single step.
* Iterate over the whole field updating the state of each
* fox and rabbit.
*/
public void simulateOneStep()
{
step++;
// Provide space for newborn animals.
List<Animal> newAnimals = new ArrayList<Animal>();
// Let all rabbits act.
for(Iterator<Animal> it = animals.iterator(); it.hasNext(); ) {
Animal animal = it.next();
animal.act(newAnimals);
if(! animal.isAlive()) {
it.remove();
}
}
// Add the newly born foxes and rabbits to the main lists.
animals.addAll(newAnimals);
view.showStatus(step, field);
}
/**
* Reset the simulation to a starting position.
*/
public void reset()
{
step = 0;
animals.clear();
populate();
// Show the starting state in the view.
view.showStatus(step, field);
}
/**
* Randomly populate the field with foxes and rabbits.
*/
private void populate()
{
Random rand = Randomizer.getRandom();
field.clear();
for(int row = 0; row < field.getDepth(); row++) {
for(int col = 0; col < field.getWidth(); col++) {
if(rand.nextDouble() <= FOX_CREATION_PROBABILITY) {
Location location = new Location(row, col);
Fox fox = new Fox(true, field, location);
animals.add(fox);
}
else if(rand.nextDouble() <= RABBIT_CREATION_PROBABILITY) {
Location location = new Location(row, col);
Rabbit rabbit = new Rabbit(true, field, location);
animals.add(rabbit);
}
// else leave the location empty.
}
}
}
}
EDIT:
Here's this same class AFTER refactoring ...
import java.util.Random;
import java.util.List;
import java.util.ArrayList;
import java.util.Iterator;
import java.awt.Color;
/**
* A simple predator-prey simulator, based on a rectangular field
* containing rabbits and foxes.
*
* Update 10.40:
* Now *almost* decoupled from the concrete animal classes.
*
* #TWiSTED_CRYSTALS
*/
public class Simulator
{
// Constants representing configuration information for the simulation.
// The default width for the grid.
private static final int DEFAULT_WIDTH = 120;
// The default depth of the grid.
private static final int DEFAULT_DEPTH = 80;
// The current state of the field.
private Field field;
// The current step of the simulation.
private int step;
// A graphical view of the simulation.
private SimulatorView view;
//Population Generator class... coupled to fox and rabbit classes
private PopulationGenerator popGenerator;
// Lists of animals in the field. Separate lists are kept for ease of iteration.
private List<Animal> animals;
/**
* Construct a simulation field with default size.
*/
public Simulator()
{
this(DEFAULT_DEPTH, DEFAULT_WIDTH);
}
/**
* Create a simulation field with the given size.
* #param depth Depth of the field. Must be greater than zero.
* #param width Width of the field. Must be greater than zero.
*/
public Simulator(int depth, int width)
{
if(width <= 0 || depth <= 0) {
System.out.println("The dimensions must be greater than zero.");
System.out.println("Using default values.");
depth = DEFAULT_DEPTH;
width = DEFAULT_WIDTH;
}
animals = new ArrayList<Animal>();
field = new Field(depth, width);
// Create a view of the state of each location in the field.
//
// view.setColor(Rabbit.class, Color.orange); // PG
// view.setColor(Fox.class, Color.blue); // PG
// Setup a valid starting point.
reset();
}
/**
* Run the simulation from its current state for a reasonably long period,
* (4000 steps).
*/
public void runLongSimulation()
{
simulate(4000);
}
/**
* Run the simulation from its current state for the given number of steps.
* Stop before the given number of steps if it ceases to be viable.
* #param numSteps The number of steps to run for.
*/
public void simulate(int numSteps)
{
for(int step = 1; step <= numSteps && view.isViable(field); step++) {
simulateOneStep();
}
}
/**
* Run the simulation from its current state for a single step.
* Iterate over the whole field updating the state of each
* fox and rabbit.
*/
public void simulateOneStep()
{
step++;
// Provide space for animals.
List<Animal> newAnimals = new ArrayList<Animal>();
// Let all animals act.
for(Iterator<Animal> it = animals.iterator(); it.hasNext(); ) {
Animal animal = it.next();
animal.act(newAnimals);
if(! animal.isAlive()) {
it.remove();
}
}
animals.addAll(newAnimals);
}
/**
* Reset the simulation to a starting position.
*/
public void reset()
{
PopulationGenerator popGenerator = new PopulationGenerator();
step = 0;
animals.clear();
popGenerator.populate();
// Show the starting state in the view.
view.showStatus(step, field);
}
public int getStep()
{
return step;
}
}
... and the new class
import java.util.ArrayList;
import java.util.Random;
import java.util.List;
import java.awt.Color;
public class PopulationGenerator
{
// The default width for the grid.
private static final int DEFAULT_WIDTH = 120;
// The default depth of the grid.
private static final int DEFAULT_DEPTH = 80;
// The probability that a fox will be created in any given grid position.
private static final double FOX_CREATION_PROBABILITY = 0.02;
// The probability that a rabbit will be created in any given grid position.
private static final double RABBIT_CREATION_PROBABILITY = 0.08;
// Lists of animals in the field. Separate lists are kept for ease of iteration.
private List<Animal> animals;
// The current state of the field.
private Field field;
// A graphical view of the simulation.
private SimulatorView view;
/**
* Constructor
*/
public PopulationGenerator()
{
animals = new ArrayList<Animal>();
field = new Field(DEFAULT_DEPTH, DEFAULT_WIDTH);
}
/**
* Randomly populate the field with foxes and rabbits.
*/
public void populate()
{
// Create a view of the state of each location in the field.
view = new SimulatorView(DEFAULT_DEPTH, DEFAULT_WIDTH);
view.setColor(Rabbit.class, Color.orange); // PG
view.setColor(Fox.class, Color.blue); // PG
Simulator simulator = new Simulator();
Random rand = Randomizer.getRandom();
field.clear();
for(int row = 0; row < field.getDepth(); row++) {
for(int col = 0; col < field.getWidth(); col++) {
if(rand.nextDouble() <= FOX_CREATION_PROBABILITY) {
Location location = new Location(row, col);
Fox fox = new Fox(true, field, location);
animals.add(fox);
}
else if(rand.nextDouble() <= RABBIT_CREATION_PROBABILITY) {
Location location = new Location(row, col);
Rabbit rabbit = new Rabbit(true, field, location);
animals.add(rabbit);
}
// else leave the location empty.
}
}
view.showStatus(simulator.getStep(), field);
}
}
here's the Field class that the PopulationGenerator calls... I havent changed this class in any way
import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Random;
/**
* Represent a rectangular grid of field positions.
* Each position is able to store a single animal.
*
* #TWiSTED_CRYSTALS
*/
public class Field
{
// A random number generator for providing random locations.
private static final Random rand = Randomizer.getRandom();
// The depth and width of the field.
private int depth, width;
// Storage for the animals.
private Object[][] field;
/**
* Represent a field of the given dimensions.
* #param depth The depth of the field.
* #param width The width of the field.
*/
public Field(int depth, int width)
{
this.depth = depth;
this.width = width;
field = new Object[depth][width];
}
/**
* Empty the field.
*/
public void clear()
{
for(int row = 0; row < depth; row++) {
for(int col = 0; col < width; col++) {
field[row][col] = null;
}
}
}
/**
* Clear the given location.
* #param location The location to clear.
*/
public void clear(Location location)
{
field[location.getRow()][location.getCol()] = null;
}
/**
* Place an animal at the given location.
* If there is already an animal at the location it will
* be lost.
* #param animal The animal to be placed.
* #param row Row coordinate of the location.
* #param col Column coordinate of the location.
*/
public void place(Object animal, int row, int col)
{
place(animal, new Location(row, col));
}
/**
* Place an animal at the given location.
* If there is already an animal at the location it will
* be lost.
* #param animal The animal to be placed.
* #param location Where to place the animal.
*/
public void place(Object animal, Location location)
{
field[location.getRow()][location.getCol()] = animal;
}
/**
* Return the animal at the given location, if any.
* #param location Where in the field.
* #return The animal at the given location, or null if there is none.
*/
public Object getObjectAt(Location location)
{
return getObjectAt(location.getRow(), location.getCol());
}
/**
* Return the animal at the given location, if any.
* #param row The desired row.
* #param col The desired column.
* #return The animal at the given location, or null if there is none.
*/
public Object getObjectAt(int row, int col)
{
return field[row][col];
}
/**
* Generate a random location that is adjacent to the
* given location, or is the same location.
* The returned location will be within the valid bounds
* of the field.
* #param location The location from which to generate an adjacency.
* #return A valid location within the grid area.
*/
public Location randomAdjacentLocation(Location location)
{
List<Location> adjacent = adjacentLocations(location);
return adjacent.get(0);
}
/**
* Get a shuffled list of the free adjacent locations.
* #param location Get locations adjacent to this.
* #return A list of free adjacent locations.
*/
public List<Location> getFreeAdjacentLocations(Location location)
{
List<Location> free = new LinkedList<Location>();
List<Location> adjacent = adjacentLocations(location);
for(Location next : adjacent) {
if(getObjectAt(next) == null) {
free.add(next);
}
}
return free;
}
/**
* Try to find a free location that is adjacent to the
* given location. If there is none, return null.
* The returned location will be within the valid bounds
* of the field.
* #param location The location from which to generate an adjacency.
* #return A valid location within the grid area.
*/
public Location freeAdjacentLocation(Location location)
{
// The available free ones.
List<Location> free = getFreeAdjacentLocations(location);
if(free.size() > 0) {
return free.get(0);
}
else {
return null;
}
}
/**
* Return a shuffled list of locations adjacent to the given one.
* The list will not include the location itself.
* All locations will lie within the grid.
* #param location The location from which to generate adjacencies.
* #return A list of locations adjacent to that given.
*/
public List<Location> adjacentLocations(Location location)
{
assert location != null : "Null location passed to adjacentLocations";
// The list of locations to be returned.
List<Location> locations = new LinkedList<Location>();
if(location != null) {
int row = location.getRow();
int col = location.getCol();
for(int roffset = -1; roffset <= 1; roffset++) {
int nextRow = row + roffset;
if(nextRow >= 0 && nextRow < depth) {
for(int coffset = -1; coffset <= 1; coffset++) {
int nextCol = col + coffset;
// Exclude invalid locations and the original location.
if(nextCol >= 0 && nextCol < width && (roffset != 0 || coffset != 0)) {
locations.add(new Location(nextRow, nextCol));
}
}
}
}
// Shuffle the list. Several other methods rely on the list
// being in a random order.
Collections.shuffle(locations, rand);
}
return locations;
}
/**
* Return the depth of the field.
* #return The depth of the field.
*/
public int getDepth()
{
return depth;
}
/**
* Return the width of the field.
* #return The width of the field.
*/
public int getWidth()
{
return width;
}
}
your problem is not in the Field class but below it. The Simulator constructor calls reset() which creates a new PopulationGenerator object, then calls populate() on that object. The populate() method calls Simulator simulator = new Simulator(); which creates a new Simulator object which continues the cycle. Solution: don't create a new Simulator object in PopulationGenerator, but instead pass the existing simulator to PopulationGenerator through its constructor or through a setSimulator(...) method.
e.g.,
class PopulationGenerator {
// ... etc...
private Simulator simulator; // null to begin with
// pass Simulator instance into constructor.
// Probably will need to do the same with SimulatorView
public PopulationGenerator(Simulator simulator, int depth, int width) {
this.simulator = simulator; // set the instance
// ... more code etc...
}
public void populate() {
// don't re-create Simulator here but rather use the instance passed in
}
}

accent indiferent regex with jTable

I've a Java regex for a RowFilter that works as a filter for information shown in a table.
The idea is that I've a table with information in it, and below the table is a text field where I write something and filters the rows only if the row has at least on cell with a regex match based on the text entered on the text field.
I've a class that extends AbstractTableModel that's the model that I use for the table. Let's suppose that the class is called ClientesTableModel.
Then I put a event in the text field, the KeyReleased one, which does the following:
private void EventFiredInTextField() {
RowFilter<ClientesTableModel, Object> rf;
try {
rf = RowFilter.regexFilter("(?i)" + jTextFieldFiltro.getText());
} catch (PatternSyntaxException ex) {
return;
}
sorter.setRowFilter(rf);
}
Already the filter is case insensitive. Any way to make it accent insensitive?
Tried what follows already, but it doesn't works if a cell has a string with accents.
private void Filtrar() {
RowFilter<ClientesTableModel, Object> rf;
try {
rf = RowFilter.regexFilter("(?i)" + Normalizer.normalize(jTextFieldFiltro.getText(), Normalizer.Form.NFD).replaceAll("\\p{InCombiningDiacriticalMarks}+", ""));
} catch (PatternSyntaxException ex) {
return;
}
sorter.setRowFilter(rf);
}
And also tried at least 20+ solutions that appears here on SO and another sites, with no luck. None of them seem to be working with a table...
Edit 1:
Tried something more:
private void Filtrar() {
RowFilter<ClientesTableModel, Object> rf;
try {
Map<String, String> replacements = new HashMap();
replacements.put("a", "[aá]");
replacements.put("e", "[eé]");
replacements.put("i", "[ií]");
replacements.put("o", "[oó]");
replacements.put("u", "[uú]");
String regex = "";
for (char c : jTextFieldFiltro.getText().toCharArray()) {
String replacement = replacements.get(Normalizer.normalize(Character.toString(Character.toLowerCase(c)), Normalizer.Form.NFD).replaceAll("\\p{InCombiningDiacriticalMarks}+", ""));
if (replacement == null) {
regex += c;
} else {
regex += replacement;
}
}
rf = RowFilter.regexFilter("(?i)" + regex);
} catch (PatternSyntaxException ex) {
return;
}
sorter.setRowFilter(rf);
}
It just makes some changes in the regex text before it's applied, with the following idea:
If the filter text is edit it will be transformed into [eé]d[ií]t, and it will be a regex that's accent indiferent for Central American letters.
However, I'm experiencing one big problem. I've the flag (?i) in the regex so it's supposed to be case insensitive. But if a cell has for example the text edÍt, the í and Í doesn't catch the (?i) flag, they aren't treated as they should, case insensitive...
A simple solution is to change replacements.put("i", "[ií]"); by replacements.put("i", "[iíÍ]");, but hey... what's the point on putting the (?i) flag then?
Anyway, this solution isn't so elegant, and it will fail for other accent types (like ¨). Ideas?
And sorter variable is of type TableRowSorter<ClientesTableModel>.
SO doesn't allows more than 30000 characters by response, so, I'm going to split this in three answers.
Part 1/3:
After try and error for 4+ hours, found a way. Not so sexy, but it's efficient and it's a real accent indiferent solution for jTables filtering with regexes.
I'd to modify some source files of JDK version 7 update 7. They're DefaultRowSorter and TableRowSorter.
I added a extra class called RowFilterSpecialFilter for coding simplification.
The modified DefaultRowSorter and TableRowSorter classes are called DefaultRowSorterSpecialFilter and TableRowSorterSpecialFilter respectively.
DefaultRowSorterSpecialFilter and RowFilterSpecialFilter are in a package called javax.swing.
TableRowSorterSpecialFilter is in a package called javax.swing.table.
TableRowSorterSpecialFilter is basically the same as TableRowSorter. The only change is that all the ocurrences of TableRowSorter where replaced by TableRowSorterSpecialFilter, and now it inherits from DefaultRowSorterSpecialFilter. Modified file source (TableRowSorterSpecialFilter.java):
/*
* Copyright (c) 2005, 2006, Oracle and/or its affiliates. All rights reserved.
* ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*/
package javax.swing.table;
import java.text.Collator;
import java.util.*;
import javax.swing.DefaultRowSorterSpecialFilter;
import javax.swing.RowFilter;
/**
* An implementation of
* <code>RowSorter</code> that provides sorting and filtering using a
* <code>TableModel</code>. The following example shows adding sorting to a
* <code>JTable</code>:
* <pre>
* TableModel myModel = createMyTableModel();
* JTable table = new JTable(myModel);
* table.setRowSorter(new TableRowSorterSpecialFilter(myModel));
* </pre> This will do all the wiring such that when the user does the
* appropriate gesture, such as clicking on the column header, the table will
* visually sort. <p>
* <code>JTable</code>'s row-based methods and
* <code>JTable</code>'s selection model refer to the view and not the
* underlying model. Therefore, it is necessary to convert between the two. For
* example, to get the selection in terms of
* <code>myModel</code> you need to convert the indices:
* <pre>
* int[] selection = table.getSelectedRows();
* for (int i = 0; i < selection.length; i++) {
* selection[i] = table.convertRowIndexToModel(selection[i]);
* }
* </pre> Similarly to select a row in
* <code>JTable</code> based on a coordinate from the underlying model do the
* inverse:
* <pre>
* table.setRowSelectionInterval(table.convertRowIndexToView(row),
* table.convertRowIndexToView(row));
* </pre> <p> The previous example assumes you have not enabled filtering. If
* you have enabled filtering
* <code>convertRowIndexToView</code> will return -1 for locations that are not
* visible in the view. <p>
* <code>TableRowSorterSpecialFilter</code> uses
* <code>Comparator</code>s for doing comparisons. The following defines how a
* <code>Comparator</code> is chosen for a column: <ol> <li>If a
* <code>Comparator</code> has been specified for the column by the
* <code>setComparator</code> method, use it. <li>If the column class as
* returned by
* <code>getColumnClass</code> is
* <code>String</code>, use the
* <code>Comparator</code> returned by
* <code>Collator.getInstance()</code>. <li>If the column class implements
* <code>Comparable</code>, use a
* <code>Comparator</code> that invokes the
* <code>compareTo</code> method. <li>If a
* <code>TableStringConverter</code> has been specified, use it to convert the
* values to
* <code>String</code>s and then use the
* <code>Comparator</code> returned by
* <code>Collator.getInstance()</code>. <li>Otherwise use the
* <code>Comparator</code> returned by
* <code>Collator.getInstance()</code> on the results from calling
* <code>toString</code> on the objects. </ol> <p> In addition to sorting
* <code>TableRowSorterSpecialFilter</code> provides the ability to filter. A
* filter is specified using the
* <code>setFilter</code> method. The following example will only show rows
* containing the string "foo":
* <pre>
* TableModel myModel = createMyTableModel();
* TableRowSorterSpecialFilter sorter = new TableRowSorterSpecialFilter(myModel);
* sorter.setRowFilter(RowFilter.regexFilter(".*foo.*"));
* JTable table = new JTable(myModel);
* table.setRowSorter(sorter);
* </pre> <p> If the underlying model structure changes (the
* <code>modelStructureChanged</code> method is invoked) the following are reset
* to their default values:
* <code>Comparator</code>s by column, current sort order, and whether each
* column is sortable. The default sort order is natural (the same as the
* model), and columns are sortable by default. <p>
* <code>TableRowSorterSpecialFilter</code> has one formal type parameter: the
* type of the model. Passing in a type that corresponds exactly to your model
* allows you to filter based on your model without casting. Refer to the
* documentation of
* <code>RowFilter</code> for an example of this. <p> <b>WARNING:</b>
* <code>DefaultTableModel</code> returns a column class of
* <code>Object</code>. As such all comparisons will be done using
* <code>toString</code>. This may be unnecessarily expensive. If the column
* only contains one type of value, such as an
* <code>Integer</code>, you should override
* <code>getColumnClass</code> and return the appropriate
* <code>Class</code>. This will dramatically increase the performance of this
* class.
*
* #param <M> the type of the model, which must be an implementation of
* <code>TableModel</code>
* #see javax.swing.JTable
* #see javax.swing.RowFilter
* #see javax.swing.table.DefaultTableModel
* #see java.text.Collator
* #see java.util.Comparator
* #since 1.6
*/
public final class TableRowSorterSpecialFilter<M extends TableModel> extends DefaultRowSorterSpecialFilter<M, Integer> {
/**
* Comparator that uses compareTo on the contents.
*/
private static final Comparator COMPARABLE_COMPARATOR =
new ComparableComparator();
/**
* Underlying model.
*/
private M tableModel;
/**
* For toString conversions.
*/
private TableStringConverter stringConverter;
/**
* Creates a
* <code>TableRowSorterSpecialFilter</code> with an empty model.
*/
public TableRowSorterSpecialFilter() {
this(null);
}
/**
* Creates a
* <code>TableRowSorterSpecialFilter</code> using
* <code>model</code> as the underlying
* <code>TableModel</code>.
*
* #param model the underlying <code>TableModel</code> to use,
* <code>null</code> is treated as an empty model
*/
public TableRowSorterSpecialFilter(M model) {
setModel(model);
}
/**
* Sets the
* <code>TableModel</code> to use as the underlying model for this
* <code>TableRowSorterSpecialFilter</code>. A value of
* <code>null</code> can be used to set an empty model.
*
* #param model the underlying model to use, or <code>null</code>
*/
public void setModel(M model) {
tableModel = model;
setModelWrapper(new TableRowSorterModelWrapper());
}
/**
* Sets the object responsible for converting values from the model to
* strings. If non-
* <code>null</code> this is used to convert any object values, that do not
* have a registered
* <code>Comparator</code>, to strings.
*
* #param stringConverter the object responsible for converting values from
* the model to strings
*/
public void setStringConverter(TableStringConverter stringConverter) {
this.stringConverter = stringConverter;
}
/**
* Returns the object responsible for converting values from the model to
* strings.
*
* #return object responsible for converting values to strings.
*/
public TableStringConverter getStringConverter() {
return stringConverter;
}
/**
* Returns the
* <code>Comparator</code> for the specified column. If a
* <code>Comparator</code> has not been specified using the
* <code>setComparator</code> method a
* <code>Comparator</code> will be returned based on the column class
* (
* <code>TableModel.getColumnClass</code>) of the specified column. If the
* column class is
* <code>String</code>,
* <code>Collator.getInstance</code> is returned. If the column class
* implements
* <code>Comparable</code> a private
* <code>Comparator</code> is returned that invokes the
* <code>compareTo</code> method. Otherwise
* <code>Collator.getInstance</code> is returned.
*
* #throws IndexOutOfBoundsException {#inheritDoc}
*/
#Override
public Comparator<?> getComparator(int column) {
Comparator comparator = super.getComparator(column);
if (comparator != null) {
return comparator;
}
Class columnClass = getModel().getColumnClass(column);
if (columnClass == String.class) {
return Collator.getInstance();
}
if (Comparable.class.isAssignableFrom(columnClass)) {
return COMPARABLE_COMPARATOR;
}
return Collator.getInstance();
}
/**
* {#inheritDoc}
*
* #throws IndexOutOfBoundsException {#inheritDoc}
*/
#Override
protected boolean useToString(int column) {
Comparator comparator = super.getComparator(column);
if (comparator != null) {
return false;
}
Class columnClass = getModel().getColumnClass(column);
if (columnClass == String.class) {
return false;
}
if (Comparable.class.isAssignableFrom(columnClass)) {
return false;
}
return true;
}
/**
* Implementation of DefaultRowSorterSpecialFilter.ModelWrapper that
* delegates to a TableModel.
*/
private class TableRowSorterModelWrapper extends ModelWrapper<M, Integer> {
#Override
public M getModel() {
return tableModel;
}
#Override
public int getColumnCount() {
return (tableModel == null) ? 0 : tableModel.getColumnCount();
}
#Override
public int getRowCount() {
return (tableModel == null) ? 0 : tableModel.getRowCount();
}
#Override
public Object getValueAt(int row, int column) {
return tableModel.getValueAt(row, column);
}
#Override
public String getStringValueAt(int row, int column) {
TableStringConverter converter = getStringConverter();
if (converter != null) {
// Use the converter
String value = converter.toString(
tableModel, row, column);
if (value != null) {
return value;
}
return "";
}
// No converter, use getValueAt followed by toString
Object o = getValueAt(row, column);
if (o == null) {
return "";
}
String string = o.toString();
if (string == null) {
return "";
}
return string;
}
#Override
public Integer getIdentifier(int index) {
return index;
}
}
private static class ComparableComparator implements Comparator {
#SuppressWarnings("unchecked")
#Override
public int compare(Object o1, Object o2) {
return ((Comparable) o1).compareTo(o2);
}
}
}
In the case of DefaultRowSorterSpecialFilter, it has more changes than TableRowSorterSpecialFilter. Basically it has a extra property, public boolean accentIndiferent which starts in false and the overrided method public String getStringValue(int index) of the nested class private class FilterEntry extends RowFilter.Entry<M, I> has been modified to return a string without accents based on the accentIndiferent value. Modified source (DefaultRowSorterSpecialFilter.java):
SO doesn't allows more than 30000 characters by response, so, I'm going to split this in three answers.
Part 2/3:
/*
* Copyright (c) 2005, 2006, Oracle and/or its affiliates. All rights reserved.
* ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*/
package javax.swing;
import java.text.Collator;
import java.text.Normalizer;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
/**
* An implementation of
* <code>RowSorter</code> that provides sorting and filtering around a
* grid-based data model. Beyond creating and installing a
* <code>RowSorter</code>, you very rarely need to interact with one directly.
* Refer to {#link javax.swing.table.TableRowSorter TableRowSorter} for a
* concrete implementation of
* <code>RowSorter</code> for
* <code>JTable</code>. <p> Sorting is done based on the current
* <code>SortKey</code>s, in order. If two objects are equal (the
* <code>Comparator</code> for the column returns 0) the next
* <code>SortKey</code> is used. If no
* <code>SortKey</code>s remain or the order is
* <code>UNSORTED</code>, then the order of the rows in the model is used. <p>
* Sorting of each column is done by way of a
* <code>Comparator</code> that you can specify using the
* <code>setComparator</code> method. If a
* <code>Comparator</code> has not been specified, the
* <code>Comparator</code> returned by
* <code>Collator.getInstance()</code> is used on the results of calling
* <code>toString</code> on the underlying objects. The
* <code>Comparator</code> is never passed
* <code>null</code>. A
* <code>null</code> value is treated as occuring before a non-
* <code>null</code> value, and two
* <code>null</code> values are considered equal. <p> If you specify a
* <code>Comparator</code> that casts its argument to a type other than that
* provided by the model, a
* <code>ClassCastException</code> will be thrown when the data is sorted. <p>
* In addition to sorting,
* <code>DefaultRowSorterSpecialFilter</code> provides the ability to
* filterInclude rows. Filtering is done by way of a
* <code>RowFilter</code> that is specified using the
* <code>setRowFilter</code> method. If no filterInclude has been specified all
* rows are included. <p> By default, rows are in unsorted order (the same as
* the model) and every column is sortable. The default
* <code>Comparator</code>s are documented in the subclasses (for example, {#link
* javax.swing.table.TableRowSorter TableRowSorter}). <p> If the underlying
* model structure changes (the
* <code>modelStructureChanged</code> method is invoked) the following are reset
* to their default values:
* <code>Comparator</code>s by column, current sort order, and whether each
* column is sortable. To find the default
* <code>Comparator</code>s, see the concrete implementation (for example, {#link
* javax.swing.table.TableRowSorter TableRowSorter}). The default sort order is
* unsorted (the same as the model), and columns are sortable by default. <p> If
* the underlying model structure changes (the
* <code>modelStructureChanged</code> method is invoked) the following are reset
* to their default values:
* <code>Comparator</code>s by column, current sort order and whether a column
* is sortable. <p>
* <code>DefaultRowSorterSpecialFilter</code> is an abstract class. Concrete
* subclasses must provide access to the underlying data by invoking
* {#code setModelWrapper}. The {#code setModelWrapper} method <b>must</b> be
* invoked soon after the constructor is called, ideally from within the
* subclass's constructor. Undefined behavior will result if you use a {#code
* DefaultRowSorterSpecialFilter} without specifying a {#code ModelWrapper}. <p>
* <code>DefaultRowSorterSpecialFilter</code> has two formal type parameters.
* The first type parameter corresponds to the class of the model, for example
* <code>DefaultTableModel</code>. The second type parameter corresponds to the
* class of the identifier passed to the
* <code>RowFilter</code>. Refer to
* <code>TableRowSorter</code> and
* <code>RowFilter</code> for more details on the type parameters.
*
* #param <M> the type of the model
* #param <I> the type of the identifier passed to the <code>RowFilter</code>
* #see javax.swing.table.TableRowSorter
* #see javax.swing.table.DefaultTableModel
* #see java.text.Collator
* #since 1.6
*/
public abstract class DefaultRowSorterSpecialFilter<M, I> extends RowSorter<M> {
public boolean accentIndiferent = false;
/**
* Whether or not we resort on TableModelEvent.UPDATEs.
*/
private boolean sortsOnUpdates;
/**
* View (JTable) -> model.
*/
private Row[] viewToModel;
/**
* model -> view (JTable)
*/
private int[] modelToView;
/**
* Comparators specified by column.
*/
private Comparator[] comparators;
/**
* Whether or not the specified column is sortable, by column.
*/
private boolean[] isSortable;
/**
* Cached SortKeys for the current sort.
*/
private SortKey[] cachedSortKeys;
/**
* Cached comparators for the current sort
*/
private Comparator[] sortComparators;
/**
* Developer supplied Filter.
*/
private RowFilter<? super M, ? super I> filter;
/**
* Value passed to the filterInclude. The same instance is passed to the
* filterInclude for different rows.
*/
private FilterEntry filterEntry;
/**
* The sort keys.
*/
private List<SortKey> sortKeys;
/**
* Whether or not to use getStringValueAt. This is indexed by column.
*/
private boolean[] useToString;
/**
* Indicates the contents are sorted. This is used if getSortsOnUpdates is
* false and an update event is received.
*/
private boolean sorted;
/**
* Maximum number of sort keys.
*/
private int maxSortKeys;
/**
* Provides access to the data we're sorting/filtering.
*/
private ModelWrapper<M, I> modelWrapper;
/**
* Size of the model. This is used to enforce error checking within the
* table changed notification methods (such as rowsInserted).
*/
private int modelRowCount;
/**
* Creates an empty
* <code>DefaultRowSorterSpecialFilter</code>.
*/
public DefaultRowSorterSpecialFilter() {
sortKeys = Collections.emptyList();
maxSortKeys = 3;
}
/**
* Sets the model wrapper providing the data that is being sorted and
* filtered.
*
* #param modelWrapper the model wrapper responsible for providing the data
* that gets sorted and filtered
* #throws IllegalArgumentException if {#code modelWrapper} is {#code null}
*/
protected final void setModelWrapper(ModelWrapper<M, I> modelWrapper) {
if (modelWrapper == null) {
throw new IllegalArgumentException(
"modelWrapper most be non-null");
}
ModelWrapper<M, I> last = this.modelWrapper;
this.modelWrapper = modelWrapper;
if (last != null) {
modelStructureChanged();
} else {
// If last is null, we're in the constructor. If we're in
// the constructor we don't want to call to overridable methods.
modelRowCount = getModelWrapper().getRowCount();
}
}
/**
* Returns the model wrapper providing the data that is being sorted and
* filtered.
*
* #return the model wrapper responsible for providing the data that gets
* sorted and filtered
*/
protected final ModelWrapper<M, I> getModelWrapper() {
return modelWrapper;
}
/**
* Returns the underlying model.
*
* #return the underlying model
*/
#Override
public final M getModel() {
return getModelWrapper().getModel();
}
/**
* Sets whether or not the specified column is sortable. The specified value
* is only checked when
* <code>toggleSortOrder</code> is invoked. It is still possible to sort on
* a column that has been marked as unsortable by directly setting the sort
* keys. The default is true.
*
* #param column the column to enable or disable sorting on, in terms of the
* underlying model
* #param sortable whether or not the specified column is sortable
* #throws IndexOutOfBoundsException if <code>column</code> is outside the
* range of the model
* #see #toggleSortOrder
* #see #setSortKeys
*/
public void setSortable(int column, boolean sortable) {
checkColumn(column);
if (isSortable == null) {
isSortable = new boolean[getModelWrapper().getColumnCount()];
for (int i = isSortable.length - 1; i >= 0; i--) {
isSortable[i] = true;
}
}
isSortable[column] = sortable;
}
/**
* Returns true if the specified column is sortable; otherwise, false.
*
* #param column the column to check sorting for, in terms of the underlying
* model
* #return true if the column is sortable
* #throws IndexOutOfBoundsException if column is outside the range of the
* underlying model
*/
public boolean isSortable(int column) {
checkColumn(column);
return (isSortable == null) ? true : isSortable[column];
}
/**
* Sets the sort keys. This creates a copy of the supplied {#code List};
* subsequent changes to the supplied {#code List} do not effect this
* {#code DefaultRowSorterSpecialFilter}. If the sort keys have changed this
* triggers a sort.
*
* #param sortKeys the new <code>SortKeys</code>; <code>null</code> is a
* shorthand for specifying an empty list, indicating that the view should
* be unsorted
* #throws IllegalArgumentException if any of the values in
* <code>sortKeys</code> are null or have a column index outside the range
* of the model
*/
#Override
public void setSortKeys(List<? extends SortKey> sortKeys) {
List<SortKey> old = this.sortKeys;
if (sortKeys != null && sortKeys.size() > 0) {
int max = getModelWrapper().getColumnCount();
for (SortKey key : sortKeys) {
if (key == null || key.getColumn() < 0
|| key.getColumn() >= max) {
throw new IllegalArgumentException("Invalid SortKey");
}
}
this.sortKeys = Collections.unmodifiableList(
new ArrayList<>(sortKeys));
} else {
this.sortKeys = Collections.emptyList();
}
if (!this.sortKeys.equals(old)) {
fireSortOrderChanged();
if (viewToModel == null) {
// Currently unsorted, use sort so that internal fields
// are correctly set.
sort();
} else {
sortExistingData();
}
}
}
/**
* Returns the current sort keys. This returns an unmodifiable
* {#code non-null List}. If you need to change the sort keys, make a copy
* of the returned {#code List}, mutate the copy and invoke
* {#code setSortKeys} with the new list.
*
* #return the current sort order
*/
#Override
public List<? extends SortKey> getSortKeys() {
return sortKeys;
}
/**
* Sets the maximum number of sort keys. The number of sort keys determines
* how equal values are resolved when sorting. For example, assume a table
* row sorter is created and
* <code>setMaxSortKeys(2)</code> is invoked on it. The user clicks the
* header for column 1, causing the table rows to be sorted based on the
* items in column 1. Next, the user clicks the header for column 2, causing
* the table to be sorted based on the items in column 2; if any items in
* column 2 are equal, then those particular rows are ordered based on the
* items in column 1. In this case, we say that the rows are primarily
* sorted on column 2, and secondarily on column 1. If the user then clicks
* the header for column 3, then the items are primarily sorted on column 3
* and secondarily sorted on column 2. Because the maximum number of sort
* keys has been set to 2 with
* <code>setMaxSortKeys</code>, column 1 no longer has an effect on the
* order. <p> The maximum number of sort keys is enforced by
* <code>toggleSortOrder</code>. You can specify more sort keys by invoking
* <code>setSortKeys</code> directly and they will all be honored. However
* if
* <code>toggleSortOrder</code> is subsequently invoked the maximum number
* of sort keys will be enforced. The default value is 3.
*
* #param max the maximum number of sort keys
* #throws IllegalArgumentException if <code>max</code> < 1
*/
public void setMaxSortKeys(int max) {
if (max < 1) {
throw new IllegalArgumentException("Invalid max");
}
maxSortKeys = max;
}
/**
* Returns the maximum number of sort keys.
*
* #return the maximum number of sort keys
*/
public int getMaxSortKeys() {
return maxSortKeys;
}
/**
* If true, specifies that a sort should happen when the underlying model is
* updated (
* <code>rowsUpdated</code> is invoked). For example, if this is true and
* the user edits an entry the location of that item in the view may change.
* The default is false.
*
* #param sortsOnUpdates whether or not to sort on update events
*/
public void setSortsOnUpdates(boolean sortsOnUpdates) {
this.sortsOnUpdates = sortsOnUpdates;
}
/**
* Returns true if a sort should happen when the underlying model is
* updated; otherwise, returns false.
*
* #return whether or not to sort when the model is updated
*/
public boolean getSortsOnUpdates() {
return sortsOnUpdates;
}
/**
* Sets the filterInclude that determines which rows, if any, should be
* hidden from the view. The filterInclude is applied before sorting. A
* value of
* <code>null</code> indicates all values from the model should be included.
* <p>
* <code>RowFilter</code>'s
* <code>include</code> method is passed an
* <code>Entry</code> that wraps the underlying model. The number of columns
* in the
* <code>Entry</code> corresponds to the number of columns in the
* <code>ModelWrapper</code>. The identifier comes from the
* <code>ModelWrapper</code> as well. <p> This method triggers a sort.
*
* #param filterInclude the filterInclude used to determine what entries
* should be included
*/
public void setRowFilter(RowFilter<? super M, ? super I> filter) {
this.filter = filter;
sort();
}
/**
* Returns the filterInclude that determines which rows, if any, should be
* hidden from view.
*
* #return the filterInclude
*/
public RowFilter<? super M, ? super I> getRowFilter() {
return filter;
}
/**
* Reverses the sort order from ascending to descending (or descending to
* ascending) if the specified column is already the primary sorted column;
* otherwise, makes the specified column the primary sorted column, with an
* ascending sort order. If the specified column is not sortable, this
* method has no effect.
*
* #param column index of the column to make the primary sorted column, in
* terms of the underlying model
* #throws IndexOutOfBoundsException {#inheritDoc}
* #see #setSortable(int,boolean)
* #see #setMaxSortKeys(int)
*/
#Override
public void toggleSortOrder(int column) {
checkColumn(column);
if (isSortable(column)) {
List<SortKey> keys = new ArrayList<>(getSortKeys());
SortKey sortKey;
int sortIndex;
for (sortIndex = keys.size() - 1; sortIndex >= 0; sortIndex--) {
if (keys.get(sortIndex).getColumn() == column) {
break;
}
}
if (sortIndex == -1) {
// Key doesn't exist
sortKey = new SortKey(column, SortOrder.ASCENDING);
keys.add(0, sortKey);
} else if (sortIndex == 0) {
// It's the primary sorting key, toggle it
keys.set(0, toggle(keys.get(0)));
} else {
// It's not the first, but was sorted on, remove old
// entry, insert as first with ascending.
keys.remove(sortIndex);
keys.add(0, new SortKey(column, SortOrder.ASCENDING));
}
if (keys.size() > getMaxSortKeys()) {
keys = keys.subList(0, getMaxSortKeys());
}
setSortKeys(keys);
}
}
private SortKey toggle(SortKey key) {
if (key.getSortOrder() == SortOrder.ASCENDING) {
return new SortKey(key.getColumn(), SortOrder.DESCENDING);
}
return new SortKey(key.getColumn(), SortOrder.ASCENDING);
}
/**
* {#inheritDoc}
*
* #throws IndexOutOfBoundsException {#inheritDoc}
*/
#Override
public int convertRowIndexToView(int index) {
if (modelToView == null) {
if (index < 0 || index >= getModelWrapper().getRowCount()) {
throw new IndexOutOfBoundsException("Invalid index");
}
return index;
}
return modelToView[index];
}
/**
* {#inheritDoc}
*
* #throws IndexOutOfBoundsException {#inheritDoc}
*/
#Override
public int convertRowIndexToModel(int index) {
if (viewToModel == null) {
if (index < 0 || index >= getModelWrapper().getRowCount()) {
throw new IndexOutOfBoundsException("Invalid index");
}
return index;
}
return viewToModel[index].modelIndex;
}
private boolean isUnsorted() {
List<? extends SortKey> keys = getSortKeys();
int keySize = keys.size();
return (keySize == 0 || keys.get(0).getSortOrder()
== SortOrder.UNSORTED);
}
/**
* Sorts the existing filtered data. This should only be used if the
* filterInclude hasn't changed.
*/
private void sortExistingData() {
int[] lastViewToModel = getViewToModelAsInts(viewToModel);
updateUseToString();
cacheSortKeys(getSortKeys());
if (isUnsorted()) {
if (getRowFilter() == null) {
viewToModel = null;
modelToView = null;
} else {
int included = 0;
for (int i = 0; i < modelToView.length; i++) {
if (modelToView[i] != -1) {
viewToModel[included].modelIndex = i;
modelToView[i] = included++;
}
}
}
} else {
// sort the data
Arrays.sort(viewToModel);
// Update the modelToView array
setModelToViewFromViewToModel(false);
}
fireRowSorterChanged(lastViewToModel);
}
/**
* Sorts and filters the rows in the view based on the sort keys of the
* columns currently being sorted and the filterInclude, if any, associated
* with this sorter. An empty
* <code>sortKeys</code> list indicates that the view should unsorted, the
* same as the model.
*
* #see #setRowFilter
* #see #setSortKeys
*/
public void sort() {
sorted = true;
int[] lastViewToModel = getViewToModelAsInts(viewToModel);
updateUseToString();
if (isUnsorted()) {
// Unsorted
cachedSortKeys = new SortKey[0];
if (getRowFilter() == null) {
// No filterInclude & unsorted
if (viewToModel != null) {
// sorted -> unsorted
viewToModel = null;
modelToView = null;
} else {
// unsorted -> unsorted
// No need to do anything.
return;
}
} else {
// There is filterInclude, reset mappings
initializeFilteredMapping();
}
} else {
cacheSortKeys(getSortKeys());
if (getRowFilter() != null) {
initializeFilteredMapping();
} else {
createModelToView(getModelWrapper().getRowCount());
createViewToModel(getModelWrapper().getRowCount());
}
// sort them
Arrays.sort(viewToModel);
// Update the modelToView array
setModelToViewFromViewToModel(false);
}
fireRowSorterChanged(lastViewToModel);
}
/**
* Updates the useToString mapping before a sort.
*/
private void updateUseToString() {
int i = getModelWrapper().getColumnCount();
if (useToString == null || useToString.length != i) {
useToString = new boolean[i];
}
for (--i; i >= 0; i--) {
useToString[i] = useToString(i);
}
}
/**
* Resets the viewToModel and modelToView mappings based on the current
* Filter.
*/
private void initializeFilteredMapping() {
int rowCount = getModelWrapper().getRowCount();
int i, j;
int excludedCount = 0;
// Update model -> view
createModelToView(rowCount);
for (i = 0; i < rowCount; i++) {
if (include(i)) {
modelToView[i] = i - excludedCount;
} else {
modelToView[i] = -1;
excludedCount++;
}
}
// Update view -> model
createViewToModel(rowCount - excludedCount);
for (i = 0, j = 0; i < rowCount; i++) {
if (modelToView[i] != -1) {
viewToModel[j++].modelIndex = i;
}
}
}
/**
* Makes sure the modelToView array is of size rowCount.
*/
private void createModelToView(int rowCount) {
if (modelToView == null || modelToView.length != rowCount) {
modelToView = new int[rowCount];
}
}
/**
* Resets the viewToModel array to be of size rowCount.
*/
private void createViewToModel(int rowCount) {
int recreateFrom = 0;
if (viewToModel != null) {
recreateFrom = Math.min(rowCount, viewToModel.length);
if (viewToModel.length != rowCount) {
Row[] oldViewToModel = viewToModel;
viewToModel = new Row[rowCount];
System.arraycopy(oldViewToModel, 0, viewToModel,
0, recreateFrom);
}
} else {
viewToModel = new Row[rowCount];
}
int i;
for (i = 0; i < recreateFrom; i++) {
viewToModel[i].modelIndex = i;
}
for (i = recreateFrom; i < rowCount; i++) {
viewToModel[i] = new Row(this, i);
}
}
/**
* Caches the sort keys before a sort.
*/
private void cacheSortKeys(List<? extends SortKey> keys) {
int keySize = keys.size();
sortComparators = new Comparator[keySize];
for (int i = 0; i < keySize; i++) {
sortComparators[i] = getComparator0(keys.get(i).getColumn());
}
cachedSortKeys = keys.toArray(new SortKey[keySize]);
}
/**
* Returns whether or not to convert the value to a string before doing
* comparisons when sorting. If true
* <code>ModelWrapper.getStringValueAt</code> will be used, otherwise
* <code>ModelWrapper.getValueAt</code> will be used. It is up to
* subclasses, such as
* <code>TableRowSorter</code>, to honor this value in their
* <code>ModelWrapper</code> implementation.
*
* #param column the index of the column to test, in terms of the underlying
SO doesn't allows more than 30000 characters by response, so, I'm going to split this in three answers.
Part 3/3:
* model
* #throws IndexOutOfBoundsException if <code>column</code> is not valid
*/
protected boolean useToString(int column) {
return (getComparator(column) == null);
}
/**
* Refreshes the modelToView mapping from that of viewToModel. If
* <code>unsetFirst</code> is true, all indices in modelToView are first set
* to -1.
*/
private void setModelToViewFromViewToModel(boolean unsetFirst) {
int i;
if (unsetFirst) {
for (i = modelToView.length - 1; i >= 0; i--) {
modelToView[i] = -1;
}
}
for (i = viewToModel.length - 1; i >= 0; i--) {
modelToView[viewToModel[i].modelIndex] = i;
}
}
private int[] getViewToModelAsInts(Row[] viewToModel) {
if (viewToModel != null) {
int[] viewToModelI = new int[viewToModel.length];
for (int i = viewToModel.length - 1; i >= 0; i--) {
viewToModelI[i] = viewToModel[i].modelIndex;
}
return viewToModelI;
}
return new int[0];
}
/**
* Sets the
* <code>Comparator</code> to use when sorting the specified column. This
* does not trigger a sort. If you want to sort after setting the comparator
* you need to explicitly invoke
* <code>sort</code>.
*
* #param column the index of the column the <code>Comparator</code> is to
* be used for, in terms of the underlying model
* #param comparator the <code>Comparator</code> to use
* #throws IndexOutOfBoundsException if <code>column</code> is outside the
* range of the underlying model
*/
public void setComparator(int column, Comparator<?> comparator) {
checkColumn(column);
if (comparators == null) {
comparators = new Comparator[getModelWrapper().getColumnCount()];
}
comparators[column] = comparator;
}
/**
* Returns the
* <code>Comparator</code> for the specified column. This will return
* <code>null</code> if a
* <code>Comparator</code> has not been specified for the column.
*
* #param column the column to fetch the <code>Comparator</code> for, in
* terms of the underlying model
* #return the <code>Comparator</code> for the specified column
* #throws IndexOutOfBoundsException if column is outside the range of the
* underlying model
*/
public Comparator<?> getComparator(int column) {
checkColumn(column);
if (comparators != null) {
return comparators[column];
}
return null;
}
// Returns the Comparator to use during sorting. Where as
// getComparator() may return null, this will never return null.
private Comparator getComparator0(int column) {
Comparator comparator = getComparator(column);
if (comparator != null) {
return comparator;
}
// This should be ok as useToString(column) should have returned
// true in this case.
return Collator.getInstance();
}
private RowFilter.Entry<M, I> getFilterEntry(int modelIndex) {
if (filterEntry == null) {
filterEntry = new FilterEntry();
}
filterEntry.modelIndex = modelIndex;
return filterEntry;
}
/**
* {#inheritDoc}
*/
#Override
public int getViewRowCount() {
if (viewToModel != null) {
// When filtering this may differ from getModelWrapper().getRowCount()
return viewToModel.length;
}
return getModelWrapper().getRowCount();
}
/**
* {#inheritDoc}
*/
#Override
public int getModelRowCount() {
return getModelWrapper().getRowCount();
}
private void allChanged() {
modelToView = null;
viewToModel = null;
comparators = null;
isSortable = null;
if (isUnsorted()) {
// Keys are already empty, to force a resort we have to
// call sort
sort();
} else {
setSortKeys(null);
}
}
/**
* {#inheritDoc}
*/
#Override
public void modelStructureChanged() {
allChanged();
modelRowCount = getModelWrapper().getRowCount();
}
/**
* {#inheritDoc}
*/
#Override
public void allRowsChanged() {
modelRowCount = getModelWrapper().getRowCount();
sort();
}
/**
* {#inheritDoc}
*
* #throws IndexOutOfBoundsException {#inheritDoc}
*/
#Override
public void rowsInserted(int firstRow, int endRow) {
checkAgainstModel(firstRow, endRow);
int newModelRowCount = getModelWrapper().getRowCount();
if (endRow >= newModelRowCount) {
throw new IndexOutOfBoundsException("Invalid range");
}
modelRowCount = newModelRowCount;
if (shouldOptimizeChange(firstRow, endRow)) {
rowsInserted0(firstRow, endRow);
}
}
/**
* {#inheritDoc}
*
* #throws IndexOutOfBoundsException {#inheritDoc}
*/
#Override
public void rowsDeleted(int firstRow, int endRow) {
checkAgainstModel(firstRow, endRow);
if (firstRow >= modelRowCount || endRow >= modelRowCount) {
throw new IndexOutOfBoundsException("Invalid range");
}
modelRowCount = getModelWrapper().getRowCount();
if (shouldOptimizeChange(firstRow, endRow)) {
rowsDeleted0(firstRow, endRow);
}
}
/**
* {#inheritDoc}
*
* #throws IndexOutOfBoundsException {#inheritDoc}
*/
#Override
public void rowsUpdated(int firstRow, int endRow) {
checkAgainstModel(firstRow, endRow);
if (firstRow >= modelRowCount || endRow >= modelRowCount) {
throw new IndexOutOfBoundsException("Invalid range");
}
if (getSortsOnUpdates()) {
if (shouldOptimizeChange(firstRow, endRow)) {
rowsUpdated0(firstRow, endRow);
}
} else {
sorted = false;
}
}
/**
* {#inheritDoc}
*
* #throws IndexOutOfBoundsException {#inheritDoc}
*/
#Override
public void rowsUpdated(int firstRow, int endRow, int column) {
checkColumn(column);
rowsUpdated(firstRow, endRow);
}
private void checkAgainstModel(int firstRow, int endRow) {
if (firstRow > endRow || firstRow < 0 || endRow < 0
|| firstRow > modelRowCount) {
throw new IndexOutOfBoundsException("Invalid range");
}
}
/**
* Returns true if the specified row should be included.
*/
private boolean include(int row) {
RowFilter<? super M, ? super I> filterInclude = getRowFilter();
if (filterInclude != null) {
return filterInclude.include(getFilterEntry(row));
}
// null filterInclude, always include the row.
return true;
}
#SuppressWarnings("unchecked")
private int compare(int model1, int model2) {
int column;
SortOrder sortOrder;
Object v1, v2;
int result;
for (int counter = 0; counter < cachedSortKeys.length; counter++) {
column = cachedSortKeys[counter].getColumn();
sortOrder = cachedSortKeys[counter].getSortOrder();
if (sortOrder == SortOrder.UNSORTED) {
result = model1 - model2;
} else {
// v1 != null && v2 != null
if (useToString[column]) {
v1 = getModelWrapper().getStringValueAt(model1, column);
v2 = getModelWrapper().getStringValueAt(model2, column);
} else {
v1 = getModelWrapper().getValueAt(model1, column);
v2 = getModelWrapper().getValueAt(model2, column);
}
// Treat nulls as < then non-null
if (v1 == null) {
if (v2 == null) {
result = 0;
} else {
result = -1;
}
} else if (v2 == null) {
result = 1;
} else {
result = sortComparators[counter].compare(v1, v2);
}
if (sortOrder == SortOrder.DESCENDING) {
result *= -1;
}
}
if (result != 0) {
return result;
}
}
// If we get here, they're equal. Fallback to model order.
return model1 - model2;
}
/**
* Whether not we are filtering/sorting.
*/
private boolean isTransformed() {
return (viewToModel != null);
}
/**
* Insets new set of entries.
*
* #param toAdd the Rows to add, sorted
* #param current the array to insert the items into
*/
private void insertInOrder(List<Row> toAdd, Row[] current) {
int last = 0;
int index;
int max = toAdd.size();
for (int i = 0; i < max; i++) {
index = Arrays.binarySearch(current, toAdd.get(i));
if (index < 0) {
index = -1 - index;
}
System.arraycopy(current, last,
viewToModel, last + i, index - last);
viewToModel[index + i] = toAdd.get(i);
last = index;
}
System.arraycopy(current, last, viewToModel, last + max,
current.length - last);
}
/**
* Returns true if we should try and optimize the processing of the
* <code>TableModelEvent</code>. If this returns false, assume the event was
* dealt with and no further processing needs to happen.
*/
private boolean shouldOptimizeChange(int firstRow, int lastRow) {
if (!isTransformed()) {
// Not transformed, nothing to do.
return false;
}
if (!sorted || (lastRow - firstRow) > viewToModel.length / 10) {
// We either weren't sorted, or to much changed, sort it all
sort();
return false;
}
return true;
}
private void rowsInserted0(int firstRow, int lastRow) {
int[] oldViewToModel = getViewToModelAsInts(viewToModel);
int i;
int delta = (lastRow - firstRow) + 1;
List<Row> added = new ArrayList<>(delta);
// Build the list of Rows to add into added
for (i = firstRow; i <= lastRow; i++) {
if (include(i)) {
added.add(new Row(this, i));
}
}
// Adjust the model index of rows after the effected region
int viewIndex;
for (i = modelToView.length - 1; i >= firstRow; i--) {
viewIndex = modelToView[i];
if (viewIndex != -1) {
viewToModel[viewIndex].modelIndex += delta;
}
}
// Insert newly added rows into viewToModel
if (added.size() > 0) {
Collections.sort(added);
Row[] lastViewToModel = viewToModel;
viewToModel = new Row[viewToModel.length + added.size()];
insertInOrder(added, lastViewToModel);
}
// Update modelToView
createModelToView(getModelWrapper().getRowCount());
setModelToViewFromViewToModel(true);
// Notify of change
fireRowSorterChanged(oldViewToModel);
}
private void rowsDeleted0(int firstRow, int lastRow) {
int[] oldViewToModel = getViewToModelAsInts(viewToModel);
int removedFromView = 0;
int i;
int viewIndex;
// Figure out how many visible rows are going to be effected.
for (i = firstRow; i <= lastRow; i++) {
viewIndex = modelToView[i];
if (viewIndex != -1) {
removedFromView++;
viewToModel[viewIndex] = null;
}
}
// Update the model index of rows after the effected region
int delta = lastRow - firstRow + 1;
for (i = modelToView.length - 1; i > lastRow; i--) {
viewIndex = modelToView[i];
if (viewIndex != -1) {
viewToModel[viewIndex].modelIndex -= delta;
}
}
// Then patch up the viewToModel array
if (removedFromView > 0) {
Row[] newViewToModel = new Row[viewToModel.length
- removedFromView];
int newIndex = 0;
int last = 0;
for (i = 0; i < viewToModel.length; i++) {
if (viewToModel[i] == null) {
System.arraycopy(viewToModel, last,
newViewToModel, newIndex, i - last);
newIndex += (i - last);
last = i + 1;
}
}
System.arraycopy(viewToModel, last,
newViewToModel, newIndex, viewToModel.length - last);
viewToModel = newViewToModel;
}
// Update the modelToView mapping
createModelToView(getModelWrapper().getRowCount());
setModelToViewFromViewToModel(true);
// And notify of change
fireRowSorterChanged(oldViewToModel);
}
private void rowsUpdated0(int firstRow, int lastRow) {
int[] oldViewToModel = getViewToModelAsInts(viewToModel);
int i, j;
int delta = lastRow - firstRow + 1;
int modelIndex;
int last;
int index;
if (getRowFilter() == null) {
// Sorting only:
// Remove the effected rows
Row[] updated = new Row[delta];
for (j = 0, i = firstRow; i <= lastRow; i++, j++) {
updated[j] = viewToModel[modelToView[i]];
}
// Sort the update rows
Arrays.sort(updated);
// Build the intermediary array: the array of
// viewToModel without the effected rows.
Row[] intermediary = new Row[viewToModel.length - delta];
for (i = 0, j = 0; i < viewToModel.length; i++) {
modelIndex = viewToModel[i].modelIndex;
if (modelIndex < firstRow || modelIndex > lastRow) {
intermediary[j++] = viewToModel[i];
}
}
// Build the new viewToModel
insertInOrder(Arrays.asList(updated), intermediary);
// Update modelToView
setModelToViewFromViewToModel(false);
} else {
// Sorting & filtering.
// Remove the effected rows, adding them to updated and setting
// modelToView to -2 for any rows that were not filtered out
List<Row> updated = new ArrayList<>(delta);
int newlyVisible = 0;
int newlyHidden = 0;
int effected = 0;
for (i = firstRow; i <= lastRow; i++) {
if (modelToView[i] == -1) {
// This row was filtered out
if (include(i)) {
// No longer filtered
updated.add(new Row(this, i));
newlyVisible++;
}
} else {
// This row was visible, make sure it should still be
// visible.
if (!include(i)) {
newlyHidden++;
} else {
updated.add(viewToModel[modelToView[i]]);
}
modelToView[i] = -2;
effected++;
}
}
// Sort the updated rows
Collections.sort(updated);
// Build the intermediary array: the array of
// viewToModel without the updated rows.
Row[] intermediary = new Row[viewToModel.length - effected];
for (i = 0, j = 0; i < viewToModel.length; i++) {
modelIndex = viewToModel[i].modelIndex;
if (modelToView[modelIndex] != -2) {
intermediary[j++] = viewToModel[i];
}
}
// Recreate viewToModel, if necessary
if (newlyVisible != newlyHidden) {
viewToModel = new Row[viewToModel.length + newlyVisible
- newlyHidden];
}
// Rebuild the new viewToModel array
insertInOrder(updated, intermediary);
// Update modelToView
setModelToViewFromViewToModel(true);
}
// And finally fire a sort event.
fireRowSorterChanged(oldViewToModel);
}
private void checkColumn(int column) {
if (column < 0 || column >= getModelWrapper().getColumnCount()) {
throw new IndexOutOfBoundsException(
"column beyond range of TableModel");
}
}
/**
* <code>DefaultRowSorterSpecialFilter.ModelWrapper</code> is responsible
* for providing the data that gets sorted by
* <code>DefaultRowSorterSpecialFilter</code>. You normally do not interact
* directly with
* <code>ModelWrapper</code>. Subclasses of
* <code>DefaultRowSorterSpecialFilter</code> provide an implementation of
* <code>ModelWrapper</code> wrapping another model. For example,
* <code>TableRowSorter</code> provides a
* <code>ModelWrapper</code> that wraps a
* <code>TableModel</code>. <p>
* <code>ModelWrapper</code> makes a distinction between values as
* <code>Object</code>s and
* <code>String</code>s. This allows implementations to provide a custom
* string converter to be used instead of invoking
* <code>toString</code> on the object.
*
* #param <M> the type of the underlying model
* #param <I> the identifier supplied to the filterInclude
* #since 1.6
* #see RowFilter
* #see RowFilter.Entry
*/
protected abstract static class ModelWrapper<M, I> {
/**
* Creates a new
* <code>ModelWrapper</code>.
*/
protected ModelWrapper() {
}
/**
* Returns the underlying model that this
* <code>Model</code> is wrapping.
*
* #return the underlying model
*/
public abstract M getModel();
/**
* Returns the number of columns in the model.
*
* #return the number of columns in the model
*/
public abstract int getColumnCount();
/**
* Returns the number of rows in the model.
*
* #return the number of rows in the model
*/
public abstract int getRowCount();
/**
* Returns the value at the specified index.
*
* #param row the row index
* #param column the column index
* #return the value at the specified index
* #throws IndexOutOfBoundsException if the indices are outside the
* range of the model
*/
public abstract Object getValueAt(int row, int column);
/**
* Returns the value as a
* <code>String</code> at the specified index. This implementation uses
* <code>toString</code> on the result from
* <code>getValueAt</code> (making sure to return an empty string for
* null values). Subclasses that override this method should never
* return null.
*
* #param row the row index
* #param column the column index
* #return the value at the specified index as a <code>String</code>
* #throws IndexOutOfBoundsException if the indices are outside the
* range of the model
*/
public String getStringValueAt(int row, int column) {
Object o = getValueAt(row, column);
if (o == null) {
return "";
}
String string = o.toString();
if (string == null) {
return "";
}
return string;
}
/**
* Returns the identifier for the specified row. The return value of
* this is used as the identifier for the
* <code>RowFilter.Entry</code> that is passed to the
* <code>RowFilter</code>.
*
* #param row the row to return the identifier for, in terms of the
* underlying model
* #return the identifier
* #see RowFilter.Entry#getIdentifier
*/
public abstract I getIdentifier(int row);
}
/**
* RowFilter.Entry implementation that delegates to the ModelWrapper.
* getFilterEntry(int) creates the single instance of this that is passed to
* the Filter. Only call getFilterEntry(int) to get the instance.
*/
private class FilterEntry extends RowFilter.Entry<M, I> {
/**
* The index into the model, set in getFilterEntry
*/
int modelIndex;
#Override
public M getModel() {
return getModelWrapper().getModel();
}
#Override
public int getValueCount() {
return getModelWrapper().getColumnCount();
}
#Override
public Object getValue(int index) {
return getModelWrapper().getValueAt(modelIndex, index);
}
#Override
public String getStringValue(int index) {
/* Original code here was:
*
* return getModelWrapper().getStringValueAt(modelIndex, index);
*/
if (accentIndiferent) {
return Normalizer.normalize((String) getModelWrapper().getStringValueAt(modelIndex, index), Normalizer.Form.NFD).replaceAll("\\p{InCombiningDiacriticalMarks}+", "");
} else {
return getModelWrapper().getStringValueAt(modelIndex, index);
}
}
#Override
public I getIdentifier() {
return getModelWrapper().getIdentifier(modelIndex);
}
}
/**
* Row is used to handle the actual sorting by way of Comparable. It will
* use the sortKeys to do the actual comparison.
*/
// NOTE: this class is static so that it can be placed in an array
private static class Row implements Comparable<Row> {
private DefaultRowSorterSpecialFilter sorter;
int modelIndex;
public Row(DefaultRowSorterSpecialFilter sorter, int index) {
this.sorter = sorter;
modelIndex = index;
}
#Override
public int compareTo(Row o) {
return sorter.compare(modelIndex, o.modelIndex);
}
}
}
And finally, a helper class, RowFilterSpecialFilter. Source (RowFilterSpecialFilter.java):
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
package javax.swing;
import java.text.Normalizer;
/**
*
* #author Miroslav
*/
public abstract class RowFilterSpecialFilter {
public static <M, I> RowFilter<M, I> regexFilterAccentIndiferent(String regex) {
return RowFilter.regexFilter("(?i)" + Normalizer.normalize(regex, Normalizer.Form.NFD).replaceAll("\\p{InCombiningDiacriticalMarks}+", ""));
}
public static <M, I> RowFilter<M, I> regexFilterAccentIndiferent(String regex, int... indices) {
return RowFilter.regexFilter("(?i)" + Normalizer.normalize(regex, Normalizer.Form.NFD).replaceAll("\\p{InCombiningDiacriticalMarks}+", ""), indices);
}
}
Now, how to use the filter with the accent indiferent function?
Instead of attaching a TableRowSorter<MyClassThatInheritsFromAbstractModel> to the jTable via setRowSorter method, attach a TableRowSorterSpecialFilter<MyClassThatInheritsFromAbstractModel> to it via the same method.
Don't forget to set accentIndiferent property to true. A simple myTableRowSorterSpecialFilterInstance.AccentIndiferent = true; is enough;
The code that should be fired up to apply a filter is what follows, where FilterText is the string that's going to be the filter:
RowFilter<ClientesTableModel, Object> rf;
try {
rf = RowFilterSpecialFilter.regexFilterAccentIndiferent("(?i)" + FilterText);
} catch (PatternSyntaxException ex) {
return;
}
sorter.setRowFilter(rf);
I've put so many sources to help to anyone that gets the same trouble that I had. I'm pretty sure that I've modified something else but I don't remember it, so, better to be sure and make a good contribution.
And... done!!!

HexapawnBoard class in Java

I have to complete 4 methods but I am having difficulty understanding them. I'm trying to complete whitemove(). I know that I have to iterate through the board, but I cannot totally understand how I'm supposed to do it!
import java.util.List;
import java.util.ArrayList;
public class HexapawnBoard {
private static final int WHITE_PIECE = 1;
private static final int BLACK_PIECE = 2;
private static final int EMPTY = 0;
private static final int BOARD_SIZE = 3;
private int[][] board;
/**
* Create a board position from a string of length BOARD_SIZE*BOARD_SIZE (9).
* The first BOARD_SIZE positions in the string correspond to the black player's home
* position. The last BOARD_SIZE positions in the string correspond ot the white player's
* home position. So, the string "BBB WWW" corresponds to a starting position.
*
* #param pos the string encoding the position of the board
*/
public HexapawnBoard(String pos)
{
if(pos.length() != BOARD_SIZE * BOARD_SIZE)
throw new RuntimeException("HexapawnBoard string must be of length BOARD_SIZExBOARD_SIZE");
board = new int[BOARD_SIZE][BOARD_SIZE];
for(int row=0;row<BOARD_SIZE;row++)
{
for(int col=0;col<BOARD_SIZE;col++)
{
switch(pos.charAt(row*BOARD_SIZE+col))
{
case 'B':
case 'b':
board[row][col] = BLACK_PIECE;
break;
case 'W':
case 'w':
board[row][col] = WHITE_PIECE;
break;
case ' ':
board[row][col] = EMPTY;
break;
default:
throw new RuntimeException("Invalid Hexapawn board pattern " + pos);
}
}
}
}
/**
* A copy constructor of HexapawnBoard
*
* #param other the other instance of HexapawnBoard to copy
*/
public HexapawnBoard(HexapawnBoard other)
{
board = new int[BOARD_SIZE][BOARD_SIZE];
for(int i=0;i<BOARD_SIZE;i++)
for(int j=0;j<BOARD_SIZE;j++)
this.board[i][j] = other.board[i][j];
}
/**
* Return a string version of the board. This uses the same format as the
* constructor (above)
*
* #return a string representation of the board.
*/
public String toString()
{
StringBuffer sb = new StringBuffer();
for(int row=0;row<BOARD_SIZE;row++)
{
for(int col=0;col<BOARD_SIZE;col++)
{
switch(board[row][col])
{
case BLACK_PIECE:
sb.append('B');
break;
case WHITE_PIECE:
sb.append('W');
break;
case EMPTY:
sb.append(' ');
break;
}
}
}
return sb.toString();
}
/**
* Determine if this board position corresponds to a winning state.
*
* #return true iff black has won.
*/
public boolean blackWins()
{
for(int col=0;col<BOARD_SIZE;col++)
if(board[BOARD_SIZE-1][col] == BLACK_PIECE)
return true;
return false;
}
/**
* Determine if this board position corresponds to a winning state
*
* #return true iff white has won
*/
public boolean whiteWins()
{
for(int col=0;col<BOARD_SIZE;col++)
if(board[0][col] == WHITE_PIECE)
return true;
return false;
}
/**
* Determine if black has a move
*
* # return truee iff black has a move
*/
public boolean blackCanMove()
{
return false;
}
/**
* Return a List of valid moves of white. Moves are represented as valid
* Hexapawn board positions. If white cannot move then the list is empty.
*
* #return A list of possible next moves for white
*/
public List<HexapawnBoard> whiteMoves()
{
return null
}
/**
* Determine if two board positions are equal
* #param other the other board position
* #return true iff they are equivalent board positions
*/
public boolean equals(HexapawnBoard other)
{
return true;
}
/**
* Determine if two board positions are reflections of each other
* #param other the other board position
* #return true iff they are equivalent board positions
*/
public boolean equalsReflection(HexapawnBoard other)
{
return true;
}
}
First of all, the code that you have so far seems to be correct.
Now, for the four methods that you have left, I can't really help you with the blackCanMove() or the whiteMoves() methods because I don't know what the rules for moving are in this hexapawn game. If you would explain the rules, I could help with that.
As far as the equals() and equalsReflection() methods go, you basically need to do what you did in the copy constructor, but instead of copying, do a conditional test. If two positions do not match up to what they are supposed to be, return false. Otherwise, once you have checked each square and they are all correct, return true.
As far as the whiteMoves() method, you need to iterate through the board and find all of the white pieces. For each white piece, there may be a few (at most 3) valid moves. Check each of those positions to see if they are possible. The piece may move diagonally if there is a black piece in that spot, or it may move forward if there is no piece at all in that spot. For each valid move, create a new HexapawnBoard representing what the board would look life following that move. At the end of the method, return a list of all of the HexapawnBoards that you created.

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