Develop Reference

I have some problems with ArrayList (quiz of head first java)

I've just started learning java since last week. I'm using book called 'head first java' and i'm struggling with solving problems about ArrayList. Error says "The method setLocationCells(ArrayList) in the type DotCom is not applicable for the
arguments (int[])" and I haven't found the solution :( help me..!
enter image description here

This looks like a Locate & Conquer type game similar to the game named Battleship with the exception that this game is a single player game played with a single hidden ship in a single horizontal row of columnar characters. Rather simplistic but kind of fun to play I suppose. The hard part is to locate the hidden ship but once you've located it, conquering (sinking) it becomes relatively easy. I'm sure this isn't the games' intent since it is after all named "The Dot Com Game" but the analogy could be possibly helpful.
There are several issues with your code but there are two major ones that just can not be there for the game to work:
Issue #1: The call to the DotCom.setLocationCells() method:
The initial problem is located within the DotComGame class on code line 13 (as the Exception indicates) where the call is made to the DotCom.setLocationCells() method. As already mentioned in comments the wrong parameter type is passed to this method. You can not pass an int[] Array to the setLocationCell() method when this method contains a parameter signature that stipulates it requires an ArrayList object. The best solution in my opinion would be to satisfy the setLocationCells() method parameter requirement...supply an ArrayList to this method.
The reason I say this is because all methods within the DotCom class work with an established ArrayList and one of the tasks of one of these methods (the checkYourself() method) actually removes elements from the ArrayList which is easy to do from a collection but very cumbersome to do the same from an Array.
To fix this problem you will need to change the data type for the locations variable located within the DotComGame class. Instead of using:
int[] locations = {randomNum, randomNum + 1, randomNum + 2};
you should have:
ArrayList<Integer> locations = new ArrayList<>(
Arrays.asList(random, randomNum + 1, randomNum + 2));
or you could do it this way:
ArrayList<Integer> locations = new ArrayList<>();
locations.add(randomNum);
locations.add(randomNum + 1);
locations.add(randomNum + 2);
There are other ways but these will do for now. Now, when the call to the setLocationCells() method is made you ahouldn't get an exception this issue should now be resolved.
Issue #2: The call to the DotCom.checkYourself() method:
Again, this particular issue is located within the DotComGame class on code line 18 where the call is made to the DotCom.checkYourself() method. Yet another parameter data type mismatch. You are trying to pass a variable of type String (named guess) to this method whereas its signature stipulates that it requires an integer (int) value. That again is a no go.
To fix this problem you will need to convert the string numerical value held by the guess variable to an Integer (int) value. So instead of having this:
while(isAlive) {
String guess = helper.getUserInput("Enter a Number: ");
String result = theDotCom.checkYourself(guess);
// ... The rest of your while loop code ...
}
you should have something like:
while(isAlive) {
String guess = helper.getUserInput("Enter a Number: ");
/* Validate. Ensure guess holds a string representation
of a Integer numerical value. */
if (!guess.matches("\\d+")) {
System.err.println("Invalid Value (" + guess
+ ") Supplied! Try again...");
continue;
}
int guessNum = Integer.parseInt(guess);
String result = theDotCom.checkYourself(guessNum);
numOfGuesses++;
if (result.equals("kill")) {
isAlive = false;
System.out.println(numOfGuesses + " guesses!");
}
else if (result.equals("hit")) {
// Do Something If You Like
System.out.println("HIT!");
}
else {
System.out.println("Missed!");
}
}
Below is a game named Simple Battleship which I based off of your code images (please don't use images for code anymore - I hate using online OCR's ;)
BattleshipGame.java - The application start class:
import java.awt.Toolkit;
public class BattleshipGame {
public static int gameLineLength = 10;
public static void main(String[] args) {
GameHelper helper = new GameHelper();
Battleship theDotCom = new Battleship();
int score = 0; // For keeping an overall score
// Display About the game...
System.out.println("Simple Battleship Game");
System.out.println("======================");
System.out.println("In this game you will be displayed a line of dashes.");
System.out.println("Each dash has the potential to hide a section of a");
System.out.println("hidden Battleship. The size of this ship is randomly");
System.out.println("chosen by the game engine and can be from 1 to 5 sections");
System.out.println("(characters) in length. The score for each battle is based");
System.out.println("on the length of the game line that will be displayed to");
System.out.println("you (default is a minimum of 10 charaters). You now have");
System.out.println("the option to supply the game line length you want to play");
System.out.println("with. If you want to use the default then just hit ENTER:");
System.out.println();
// Get the desire game line length
String length = helper.getUserInput("Desired Game Line Length: --> ", "Integer", true, 10, 10000);
if (!length.isEmpty()) {
gameLineLength = Integer.parseInt(length);
}
System.out.println();
// Loop to allow for continuous play...
boolean alwaysReplay = true;
while (alwaysReplay) {
int numOfGuesses = 0;
/* Create a random ship size to hide within the line.
It could be a size from 1 to 5 characters in length. */
int shipSize = new java.util.Random().nextInt((5 - 1) + 1) + 1;
int randomNum = (int) (Math.random() * (gameLineLength - (shipSize - 1)));
int[] locations = new int[shipSize];
for (int i = 0; i < locations.length; i++) {
locations[i] = randomNum + i;
}
System.out.println("Destroy the " + shipSize + " character ship hidden in the");
System.out.println("displayed line below:");
System.out.println();
String gameLine = String.join("", java.util.Collections.nCopies(gameLineLength, "-"));
theDotCom.setLocationCells(locations);
// Play current round...
boolean isAlive = true;
while (isAlive == true) {
System.out.println(gameLine);
String guess = helper.getUserInput("Enter a number from 1 to " + gameLineLength
+ " (0 to quit): --> ", "Integer", 1, gameLineLength);
int idx = Integer.parseInt(guess);
if (idx == 0) {
System.out.println("Quiting with an overall score of: " + score + " ... Bye-Bye");
alwaysReplay = false;
break;
}
idx = idx - 1;
String result = theDotCom.checkYourself(idx);
numOfGuesses++;
System.out.println(result);
if (result.equalsIgnoreCase("kill")) {
Toolkit.getDefaultToolkit().beep();
isAlive = false;
/* Tally the score dependent upon the gameLineLength... */
if (gameLineLength <= 10) { score += 5; }
else if (gameLineLength > 10 && gameLineLength <= 20) { score += 10; }
else if (gameLineLength > 20 && gameLineLength <= 30) { score += 15; }
else if (gameLineLength > 30 && gameLineLength <= 40) { score += 20; }
else { score += 25; }
gameLine = gameLine.substring(0, idx) + "x" + gameLine.substring(idx + 1);
System.out.println(gameLine);
System.out.println(numOfGuesses + " guesses were made to sink the hidden ship.");
System.out.println("Your overall score is: " + (score < 0 ? 0 : score));
}
else if (result.equalsIgnoreCase("hit")) {
gameLine = gameLine.substring(0, idx) + "x" + gameLine.substring(idx + 1);
}
if (result.equalsIgnoreCase("miss")) {
score -= 1;
}
System.out.println();
}
// Play Again? [but only if 'alwaysReplay' holds true]
if (alwaysReplay) {
String res = helper.getAnything("<< Press ENTER to play again >>\n"
+ "<< or enter 'q' to quit >>");
if (res.equalsIgnoreCase("q")) {
System.out.println("Quiting with an overall score of: " + score + " ... Bye-Bye");
break;
}
System.out.println();
}
}
}
}
GameHelper.java - The GameHelper class:
import java.util.Scanner;
public class GameHelper {
private final Scanner in = new Scanner(System.in);
public String getUserInput(String prompt, String responseType, int... minMAX) {
int min = 0, max = 0;
if (minMAX.length == 2) {
min = minMAX[0];
max = minMAX[1];
}
if (minMAX.length > 0 && min < 1 || max < 1) {
throw new IllegalArgumentException("\n\ngetUserInput() Method Error! "
+ "The optional parameters 'min' and or 'max' can not be 0!\n\n");
}
String response = "";
while (response.isEmpty()) {
if (prompt.trim().endsWith("-->")) {
System.out.print(prompt);
}
else {
System.out.println(prompt);
}
response = in.nextLine().trim();
if (responseType.matches("(?i)\\b(int|integer|float|double)\\b")) {
if (!response.matches("-?\\d+(\\.\\d+)?") ||
(responseType.toLowerCase().startsWith("int") && response.contains("."))) {
System.err.println("Invalid Entry (" + response + ")! Try again...");
response = "";
continue;
}
}
// Check entry range value if the entry is to be an Integer
if (responseType.toLowerCase().startsWith("int")) {
int i = Integer.parseInt(response);
if (i != 0 && (i < min || i > max)) {
System.err.println("Invalid Entry (" + response + ")! Try again...");
response = "";
}
}
}
return response;
}
public String getUserInput(String prompt, String responseType, boolean allowNothing, int... minMAX) {
int min = 0, max = 0;
if (minMAX.length == 2) {
min = minMAX[0];
max = minMAX[1];
}
if (minMAX.length > 0 && min < 1 || max < 1) {
throw new IllegalArgumentException("\n\ngetUserInput() Method Error! "
+ "The optional parameters 'min' and or 'max' can not be 0!\n\n");
}
String response = "";
while (response.isEmpty()) {
if (prompt.trim().endsWith("-->")) {
System.out.print(prompt);
}
else {
System.out.println(prompt);
}
response = in.nextLine().trim();
if (response.isEmpty() && allowNothing) {
return "";
}
if (responseType.matches("(?i)\\b(int|integer|float|double)\\b")) {
if (!response.matches("-?\\d+(\\.\\d+)?") ||
(responseType.toLowerCase().startsWith("int") && response.contains("."))) {
System.err.println("Invalid Entry (" + response + ")! Try again...");
response = "";
continue;
}
}
// Check entry range value if the entry is to be an Integer
if (responseType.toLowerCase().startsWith("int")) {
int i = Integer.parseInt(response);
if (i != 0 && (i < min || i > max)) {
System.err.println("Invalid Entry (" + response + ")! Try again...");
response = "";
}
}
}
return response;
}
public String getAnything(String prompt) {
if (prompt.trim().endsWith("-->")) {
System.out.print(prompt);
}
else {
System.out.println(prompt);
}
return in.nextLine().trim();
}
}
Battleship.java - The Battleship class:
import java.util.ArrayList;
public class Battleship {
private ArrayList<Integer> locationCells;
public void setLocationCells(java.util.ArrayList<Integer> loc) {
locationCells = loc;
}
// Overload Method (Java8+)
public void setLocationCells(int[] loc) {
locationCells = java.util.stream.IntStream.of(loc)
.boxed()
.collect(java.util.stream.Collectors
.toCollection(java.util.ArrayList::new));
}
/*
// Overload Method (Before Java8)
public void setLocationCells(int[] loc) {
// Clear the ArrayList in case it was previously loaded.
locationCells.clear();
// Fill the ArrayList with integer elements from the loc int[] Array
for (int i = 0; i < loc.length; i++) {
locationCells.add(loc[i]);
}
}
*/
/**
* Completely removes one supplied Integer value from all elements
* within the supplied Integer Array if it exist.<br><br>
*
* <b>Example Usage:</b><pre>
*
* {#code int[] a = {103, 104, 100, 10023, 10, 140, 2065};
* a = removeFromArray(a, 104);
* System.out.println(Arrays.toString(a);
*
* // Output will be: [103, 100, 10023, 10, 140, 2065]}</pre>
*
* #param srcArray (Integer Array) The Integer Array to remove elemental
* Integers from.<br>
*
* #param intToDelete (int) The Integer to remove from elements within the
* supplied Integer Array.<br>
*
* #return A Integer Array with the desired elemental Integers removed.
*/
public static int[] removeFromArray(int[] srcArray, int intToDelete) {
int[] arr = {};
int cnt = 0;
boolean deleteIt = false;
for (int i = 0; i < srcArray.length; i++) {
if (srcArray[i] != intToDelete) {
arr[cnt] = srcArray[i];
cnt++;
}
}
return arr;
}
public String checkYourself(int userInput) {
String result = "MISS";
int index = locationCells.indexOf(userInput);
if (index >= 0) {
locationCells.remove(index);
if (locationCells.isEmpty()) {
result = "KILL";
}
else {
result = "HIT";
}
}
return result;
}
}

Fastest way to find all cycles in a big directed graph

I have to find all the cycles in a directed graph where every node has to only go out to 1 node but it can have more than one come in towards it and print all the nodes that are in a cycle.
Is there anyway I can make [my code][1] run faster?
right now it runs 100k nodes at about 4s but the time-limit is 1.5s
import java.io.*;
import java.util.*;
public class Main {
public static void main (String[] args) throws IOException {
long startTime = 0;
BufferedReader input = new BufferedReader(new InputStreamReader(System.in));
BufferedWriter output = new BufferedWriter(new OutputStreamWriter(System.out));
int numOfPeople = Integer.parseInt(input.readLine());
StringTokenizer following = new StringTokenizer(input.readLine(), " ");
startTime = System.nanoTime();
int[] people = new int[numOfPeople], // index -> personID, value -> personID's friend
winningPotentials = new int[numOfPeople]; // index -> personID, value -> personID's winningPotential
Arrays.fill(winningPotentials, 50);
// adding followings of people
for (int i = 0 ; i < numOfPeople ; i++) {
people[i] = Integer.parseInt(following.nextToken()) - 1;
}
/*
SETTING WINNER POTENTIALS
*/
int numOfWinners = 0;
for (int person : people) {
if (winningPotentials[person] == 50) {
Deque<Integer> path = new ArrayDeque<>();
path.addLast(person);
while (true) {
int friend = people[person];
if (path.contains(friend)) {
// all those in a friend group are winningPot = 100
while (path.getLast() != friend) {
if (winningPotentials[path.peekLast()] != 100) {
numOfWinners++;
winningPotentials[path.peekLast()] = 100;
}
path.removeLast();
}
if (winningPotentials[path.peekLast()] != 100) {
numOfWinners++;
winningPotentials[path.peekLast()] = 100;
}
path.removeLast();
break;
}
// if friend hasn't been checked before, repeat
else {
path.addLast(friend);
person = friend;
}
}
// anyone in the path that wasnt in a friend group is winnerPot=0
for (int person2 : path)
winningPotentials[person2] = 0;
}
}
/*
PRINTING THE RESULTS
*/
StringBuilder sb = new StringBuilder();
sb.append(numOfWinners + "\n");
// print each winner
for (int i = 0 ; i < winningPotentials.length ; i++)
if (winningPotentials[i] == 100)
sb.append((i + 1) + " ");
sb.append("\nExecution Time ->\t" + ((System.nanoTime() - startTime) / 1000000) + "ms");
output.write(sb.toString());
output.flush();
output.close();
}
}

Why do you need a BufferedWriter ? Can you just not do a System.out.println(sb.toString()) ?

This can be implemented as a modified BFS algorithm.
Difference is what whenever you see a point that has already been added to the queue, and isn't the point before the one you were just at, you have found a cycle. So when you add points to the queue you add the current path to that point instead of just the point, but you also add the adjacent point (the last on the path) to a list of already found points.
I would probably wait to calculate the winning Potentials until you have found all the cycles.

Java 8 Search ArrayList with Streams algorithm failing

We are using a Stream to search an ArrayList of strings the Dictionary file is sorted & contains 307107 words all in lower case
We are using the findFirst to look for a match from the text in a TextArea
As long as the word is misspelled beyond the 3 character the search has favoriable results
If the misspelled word is like this "Charriage" the results are nothing close to a match
The obvious goal is to get as close to correct without the need to look at an enormous number of words
Here is the text we are tesing
Tak acheive it hommaker and aparent as Chariage NOT ME Charriag add missing vowel to Cjarroage
We have made some major changes to the stream search filters with reasonable improvements
We will edit the posted code to include ONLY the part of the code where the search is failing
And below that the code changes made to the stream filters
Before the code change if the searchString had a misspelled char at position 1 no results were found in the dictionary the new search filters fixed that
We also added more search information by increasing the number of char for endsWith
So what is still failing! If the searchString(misspelled word) is missing a char at the end of the word and if the word has an incorrect char from position 1 to 4 the search fails
We are working on adding & removing char but we are not sure this is a workable solution
Comments or code will be greatly appreciated if you would like the complete project we will post on GitHub Just ask in the comments
The question is still how to fix this search filter when multiple char are missing from the misspelled word?
After multiple hours of searching for a FREE txt Dictionary this is one of the best
A side bar fact it has 115726 words that are > 5 in length and have a vowel at the end of the word. That means it has 252234 words with no vowel at the end
Does that mean we have a 32% chance of fixing the issue by adding a vowel to the end of the searchString? NOT a question just an odd fact!
HERE is a link to the dictionary download and place the words_alpha.txt file on C drive at C:/A_WORDS/words_alpha.txt");
words_alpha.txt
Code Before Changes
}if(found != true){
lvListView.setStyle("-fx-font-size:18.0;-fx-background-color: white;-fx-font-weight:bold;");
for(int indexSC = 0; indexSC < simpleArray.length;indexSC++){
String NewSS = txtMonitor.getText().toLowerCase();
if(NewSS.contains(" ")||(NewSS.matches("[%&/0-9]"))){
String NOT = txtMonitor.getText().toLowerCase();
txtTest.setText(NOT+" Not in Dictionary");
txaML.appendText(NOT+" Not in Dictionary");
onCheckSpelling();
return;
}
int a = NewSS.length();
int Z;
if(a == 0){// manage CR test with two CR's
Z = 0;
}else if(a == 3){
Z = 3;
}else if(a > 3 && a < 5){
Z = 4;
}else if(a >= 5 && a < 8){
Z = 4;
}else{
Z = 5;
}
System.out.println("!!!! NewSS "+NewSS+" a "+a+" ZZ "+Z);
if(Z == 0){// Manage CR in TextArea
noClose = true;
strSF = "AA";
String NOT = txtMonitor.getText().toLowerCase();
//txtTo.setText("Word NOT in Dictionary");// DO NO SEARCH
//txtTest.setText("Word NOT in Dictionaary");
txtTest.setText("Just a Space");
onCheckSpelling();
}else{
txtTest.setText("");
txaML.clear();
txtTest.setText("Word NOT in Dictionaary");
txaML.appendText("Word NOT in Dictionaary");
String strS = searchString.substring(0,Z).toLowerCase();
strSF = strS;
}
// array & list use in stream to add results to ComboBox
List<String> cs = Arrays.asList(simpleArray);
ArrayList<String> list = new ArrayList<>();
cs.stream().filter(s -> s.startsWith(strSF))
//.forEach(System.out::println);
.forEach(list :: add);
for(int X = 0; X < list.size();X++){
String A = (String) list.get(X);
Improved New Code
}if(found != true){
for(int indexSC = 0; indexSC < simpleArray.length;indexSC++){
String NewSS = txtMonitor.getText().toLowerCase();
if(NewSS.contains(" ")||(NewSS.matches("[%&/0-9]"))){
String NOT = txtMonitor.getText().toLowerCase();
txtTest.setText(NOT+" Not in Dictionary");
onCheckSpelling();
return;
}
int a = NewSS.length();
int Z;
if(a == 0){// manage CR test with two CR's
Z = 0;
}else if(a == 3){
Z = 3;
}else if(a > 3 && a < 5){
Z = 4;
}else if(a >= 5 && a < 8){
Z = 4;
}else{
Z = 5;
}
if(Z == 0){// Manage CR
noClose = true;
strSF = "AA";
String NOT = txtMonitor.getText().toLowerCase();
txtTest.setText("Just a Space");
onCheckSpelling();
}else{
txtTest.setText("");
txtTest.setText("Word NOT in Dictionaary");
String strS = searchString.substring(0,Z).toLowerCase();
strSF = strS;
}
ArrayList list = new ArrayList<>();
List<String> cs = Arrays.asList(simpleArray);
// array list & list used in stream foreach filter results added to ComboBox
// Code below provides variables for refined search
int W = txtMonitor.getText().length();
String nF = txtMonitor.getText().substring(0, 1).toLowerCase();
String nE = txtMonitor.getText().substring(W - 2, W);
if(W > 7){
nM = txtMonitor.getText().substring(W-5, W);
System.out.println("%%%%%%%% nE "+nE+" nF "+nF+" nM = "+nM);
}else{
nM = txtMonitor.getText().substring(W-1, W);
System.out.println("%%%%%%%% nE "+nE+" nF "+nF+" nM = "+nM);
}
cs.stream().filter(s -> s.startsWith(strSF)
|| s.startsWith(nF, 0)
&& s.length()<= W+2
&& s.endsWith(nE)
&& s.startsWith(nF)
&& s.contains(nM))
.forEach(list :: add);
for(int X = 0; X < list.size();X++){
String A = (String) list.get(X);
sort(list);
cboSelect.setStyle("-fx-font-weight:bold;-fx-font-size:18.0;");
cboSelect.getItems().add(A);
}// Add search results to cboSelect
break;
Here is a screen shot of the FXML file the controls are named the same as the names used in our code with the exception of the ComboBox

I am adding a JavaFX answer. This app uses Levenshtein Distance. You have to click on Check Spelling to start. You can select a word from the list to replace the current word being checked. I notice Levenshtein Distance returns lots of words so you might want to find other ways to reduce the list down even more.
Main
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.ListView;
import javafx.scene.control.TextArea;
import javafx.scene.control.TextField;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
public class App extends Application
{
public static void main(String[] args)
{
launch(args);
}
TextArea taWords = new TextArea("Tak Carrage thiss on hoemaker answe");
TextField tfCurrentWordBeingChecked = new TextField();
//TextField tfMisspelledWord = new TextField();
ListView<String> lvReplacementWords = new ListView();
TextField tfReplacementWord = new TextField();
Button btnCheckSpelling = new Button("Check Spelling");
Button btnReplaceWord = new Button("Replace Word");
List<String> wordList = new ArrayList();
List<String> returnList = new ArrayList();
HandleLevenshteinDistance handleLevenshteinDistance = new HandleLevenshteinDistance();
ObservableList<String> listViewData = FXCollections.observableArrayList();
#Override
public void start(Stage primaryStage)
{
setupListView();
handleBtnCheckSpelling();
handleBtnReplaceWord();
VBox root = new VBox(taWords, tfCurrentWordBeingChecked, lvReplacementWords, tfReplacementWord, btnCheckSpelling, btnReplaceWord);
root.setSpacing(5);
Scene scene = new Scene(root);
primaryStage.setScene(scene);
primaryStage.show();
}
public void handleBtnCheckSpelling()
{
btnCheckSpelling.setOnAction(actionEvent -> {
if (btnCheckSpelling.getText().equals("Check Spelling")) {
wordList = new ArrayList(Arrays.asList(taWords.getText().split(" ")));
returnList = new ArrayList(Arrays.asList(taWords.getText().split(" ")));
loadWord();
btnCheckSpelling.setText("Check Next Word");
}
else if (btnCheckSpelling.getText().equals("Check Next Word")) {
loadWord();
}
});
}
public void handleBtnReplaceWord()
{
btnReplaceWord.setOnAction(actionEvent -> {
int indexOfWordToReplace = returnList.indexOf(tfCurrentWordBeingChecked.getText());
returnList.set(indexOfWordToReplace, tfReplacementWord.getText());
taWords.setText(String.join(" ", returnList));
btnCheckSpelling.fire();
});
}
public void setupListView()
{
lvReplacementWords.setItems(listViewData);
lvReplacementWords.getSelectionModel().selectedItemProperty().addListener((obs, oldSelection, newSelection) -> {
tfReplacementWord.setText(newSelection);
});
}
private void loadWord()
{
if (wordList.size() > 0) {
tfCurrentWordBeingChecked.setText(wordList.get(0));
wordList.remove(0);
showPotentialCorrectSpellings();
}
}
private void showPotentialCorrectSpellings()
{
List<String> potentialCorrentSpellings = handleLevenshteinDistance.getPotentialCorretSpellings(tfCurrentWordBeingChecked.getText().trim());
listViewData.setAll(potentialCorrentSpellings);
}
}
CustomWord Class
/**
*
* #author blj0011
*/
public class CustomWord
{
private int distance;
private String word;
public CustomWord(int distance, String word)
{
this.distance = distance;
this.word = word;
}
public String getWord()
{
return word;
}
public void setWord(String word)
{
this.word = word;
}
public int getDistance()
{
return distance;
}
public void setDistance(int distance)
{
this.distance = distance;
}
#Override
public String toString()
{
return "CustomWord{" + "distance=" + distance + ", word=" + word + '}';
}
}
HandleLevenshteinDistance Class
/**
*
* #author blj0011
*/
public class HandleLevenshteinDistance
{
private List<String> dictionary = new ArrayList<>();
public HandleLevenshteinDistance()
{
try {
//Load DictionaryFrom file
//See if the dictionary file exists. If it don't download it from Github.
File file = new File("alpha.txt");
if (!file.exists()) {
FileUtils.copyURLToFile(
new URL("https://raw.githubusercontent.com/dwyl/english-words/master/words_alpha.txt"),
new File("alpha.txt"),
5000,
5000);
}
//Load file content to a List of Strings
dictionary = FileUtils.readLines(file, Charset.forName("UTF8"));
}
catch (IOException ex) {
ex.printStackTrace();
}
}
public List<String> getPotentialCorretSpellings(String misspelledWord)
{
LevenshteinDistance levenshteinDistance = new LevenshteinDistance();
List<CustomWord> customWords = new ArrayList();
dictionary.stream().forEach((wordInDictionary) -> {
int distance = levenshteinDistance.apply(misspelledWord, wordInDictionary);
if (distance <= 2) {
customWords.add(new CustomWord(distance, wordInDictionary));
}
});
Collections.sort(customWords, (CustomWord o1, CustomWord o2) -> o1.getDistance() - o2.getDistance());
List<String> returnList = new ArrayList();
customWords.forEach((item) -> {
System.out.println(item.getDistance() + " - " + item.getWord());
returnList.add(item.getWord());
});
return returnList;
}
}

You just needed to go a little further out into the Dictionary
We are sure you were getting a lot of suggested words from the Dictionary?
We tested your code and sometimes it found 3000 or more possible matches WOW
So here is the BIG improvement. It still needs a lot of testing we used this line for our tests with 100% favorable results.
Tske Charriage to hommaker and hommake as hommaer
Our fear is if the speller really butchers the word this improvement might solve that degree of misspelling
We are sure you know that if the first letter is wrong this will not work
Like zenophobe for xenophobe
Here is the BIG improvement tada
cs.stream().filter(s -> s.startsWith(strSF)
|| s.startsWith(nF, 0)
&& s.length() > 1 && s.length() <= W+3 // <== HERE
&& s.endsWith(nE)
&& s.startsWith(nF)
&& s.contains(nM))
.forEach(list :: add);
You can send the check to my address 55 48 196 195

This question is a possible duplicate: Search suggestion in strings
I think you should be using something similar to Levenshtein Distance or Jaro Winkler Distance. If you can use Apache's Commons. I would suggest using Apache Commons Lang. It has an implementation of Levenshtein Distance. The example demos this implementation. If you set the distance to (distance <= 2), you will potentially get more results.
import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.nio.charset.Charset;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.apache.commons.io.FileUtils;
import org.apache.commons.lang3.StringUtils;
/**
*
* #author blj0011
*/
public class Main
{
public static void main(String[] args)
{
try {
System.out.println("Hello World!");
File file = new File("alpha.txt");
if (!file.exists()) {
FileUtils.copyURLToFile(
new URL("https://raw.githubusercontent.com/dwyl/english-words/master/words_alpha.txt"),
new File("alpha.txt"),
5000,
5000);
}
List<String> lines = FileUtils.readLines(file, Charset.forName("UTF8"));
//lines.forEach(System.out::println);
lines.stream().forEach(line -> {
int distance = StringUtils.getLevenshteinDistance(line, "zorilta");
//System.out.println(line + ": " + distance);
if (distance <= 1) {
System.out.println("Did you mean: " + line);
}
});
}
catch (IOException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
Output distance <= 1
Building JavaTestingGround 1.0
------------------------------------------------------------------------
--- exec-maven-plugin:1.5.0:exec (default-cli) # JavaTestingGround ---
Hello World!
Did you mean: zorilla
------------------------------------------------------------------------
BUILD SUCCESS
------------------------------------------------------------------------
Total time: 1.329 s
Finished at: 2019-11-01T11:02:48-05:00
Final Memory: 7M/30M
Distance <= 2
Hello World!
Did you mean: corita
Did you mean: gorilla
Did you mean: zoril
Did you mean: zorilla
Did you mean: zorillas
Did you mean: zorille
Did you mean: zorillo
Did you mean: zorils
------------------------------------------------------------------------
BUILD SUCCESS
------------------------------------------------------------------------
Total time: 1.501 s
Finished at: 2019-11-01T14:03:33-05:00
Final Memory: 7M/34M
See the possible duplicate for more details about Levenshtein Distance.

Issue with NullPointerException

I am continuing to get this error. Now I have gotten it for my SortSearchUtil. I've tried to do some debugging but can fix the issue. The error reads:
----jGRASP exec: java PostOffice
Exception in thread "main" java.lang.NullPointerException
at SortSearchUtil.selectionSort(SortSearchUtil.java:106)
at PostOffice.sortLetters(PostOffice.java:73)
at PostOffice.main(PostOffice.java:15)
----jGRASP wedge: exit code for process is 1.
----jGRASP: operation complete.
line 106 of selection Sort is:
if (array[indexSmallest].compareTo(array[curPos]) > 0)
I don't know what could be wrong with my method. It's a standard method that was given to me by my instructor. I've tried to debug my program but I'm pretty stuck. Here is the method that the error is originating from, selectionSort:
public static void selectionSort(Comparable[] array)
{
int curPos, indexSmallest, start;
Comparable temp;
for (start = 0; start < array.length - 1; start++)
{
indexSmallest = start;
for (curPos = start + 1; curPos < array.length; curPos++)
if (array[indexSmallest].compareTo(array[curPos]) > 0)
{
indexSmallest = curPos;
}
// end for
temp = array[start];
array[start] = array[indexSmallest];
array[indexSmallest] = temp;
} // end for
}
The sort method is at the bottom which calls SortSearchUtil.selectionSort of this Post Office Method:
import java.util.*;
import java.io.*;
public class PostOffice
{
private final int max = 1000;
private Letter [] ltrAra = new Letter[max];
private int count;
public static void main(String [] args)
{
PostOffice postOffice = new PostOffice();
postOffice.readLetters("letters.in");
postOffice.sortLetters();
postOffice.printLetters();
}
public PostOffice()
{
Letter [] Letters = ltrAra;
this.count = 0;
}
public void readLetters(String filename)
{
int count = 0;
int iWork = 0;
Scanner fin = new Scanner(filename);
String toName, toStreet, toCity, toState, toZip;
String fromName, fromStreet, fromCity, fromState, fromZip, temp;
double weight;
String sWork;
fin = FileUtil.openInputFile(filename);
if (fin != null)
{
while (fin.hasNext())
{
toName = fin.nextLine();
toStreet = fin.nextLine();
sWork = fin.nextLine();
iWork = sWork.indexOf(",");
toCity = sWork.substring(0, iWork);
iWork = iWork + 2;
toState = sWork.substring(iWork, iWork + 2);
iWork = iWork + 3;
toZip = sWork.substring(iWork);
fromName = fin.nextLine();
fromStreet = fin.nextLine();
sWork = fin.nextLine();
iWork = sWork.indexOf(",");
fromCity = sWork.substring(0, iWork);
iWork = iWork + 2;
fromState = sWork.substring(iWork, iWork + 2);
iWork = iWork + 3;
fromZip = sWork.substring(iWork);
sWork = fin.nextLine();
weight = Double.parseDouble(sWork);
ltrAra[count] = new Letter(toName, toStreet, toCity, toState, toZip, fromName, fromStreet, fromCity, fromState, fromZip, weight);
count++;
}
fin.close();
}
}
public void sortLetters()
{
SortSearchUtil.selectionSort(ltrAra);
}
public void printLetters()
{
for (Letter ltr : ltrAra)
{
System.out.println(ltr);
System.out.println();
}
}
}
My file looks like this "letters.in":
Stu Steiner
123 Slacker Lane
Slackerville, IL 09035
Tom Capaul
999 Computer Nerd Court
Dweebsville, NC 28804-1359
0.50
Tom Capaul
999 Computer Nerd Court
Dweebsville, NC 28804-1359
Chris Peters
123 Some St.
Anytown, CA 92111-0389
1.55

Obviously you get a NPE because:
You initialize ltrAra as array of 1000 items, but you read in less than 1000 items within method readLetters(). So at the end of this array some null references remain un-initialized (remember array-creation does itself not set the single items to any objects). Therefore following sorting-method gets some null-references => NPE.
Suggested solution:
You should use an ArrayList instead of an array because that will automatically prevent you from accessing too much items due to internal range check.

In addition to the above answer that Meno has well stated, you need to understand when you get a Null pointer Exception.
your error-line : if (array[indexSmallest].compareTo(array[curPos]) > 0)
If we get NPE in this line, it is obvious that array[indexSmallest] is null
And when you invoke an action on null, you get NPE. Hope this helps you to debug, down the line.
Also, One of the main reasons when we choose ArrayList over Arrays is when we do not know the length of the array.
One more suggestion, you can create an ArrayList and then convert to Arrays if you want to stick with Arrays
To convert ArrayList of any class into array, Convert T to the respective class. For eg: if you want String array, convert T to 'String'
List<T> list = new ArrayList<T>();
T [] students = list.toArray(new T[list.size()]);

Sentiment analysis using SentiWordNet

I am in desperate need for some help with the following.
For my master thesis I have to conduct a sentiment analysis on some Amazon, Twitter and Facebook data. I have saved these data in a csv document. Now I want to use SentiWordNet to obtain the polarity scores. However I'm unable to run the script provided on their website using python.
First of all I have to say that I am completely new to Java. So please don't blame me for not knowing it all. I have spent a lot of time searching on the internet for some information or tutorials with no luck. There was one topic on this site from a person with a similar problem (How to use SentiWordNet), although I came across a different problem. Whenever I run the script below, I get the following message: ImportError: No module named java.io.BufferedReader. I tried to search on the internet for a solution, but I couldn't find any. Could someone please help me out with how to run this script. For starters, I have already removed the garbage in the sentiwordnet.txt file. The pathway to the SentiWordNet.txt file is \Users\Mo\Documents\etc. This is also the pathway for the csv file. Btw I'm running this script on OSX with python 2.7.5.
Thank you so much in advance for your help!!!
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Set;
import java.util.Vector;
public class SWN3 {
private String pathToSWN = "data"+File.separator+"SentiWordNet_3.0.0.txt";
private HashMap<String, String> _dict;
public SWN3(){
_dict = new HashMap<String, String>();
HashMap<String, Vector<Double>> _temp = new HashMap<String, Vector<Double>>();
try{
BufferedReader csv = new BufferedReader(new FileReader(pathToSWN));
String line = "";
while((line = csv.readLine()) != null)
{
String[] data = line.split("\t");
Double score = Double.parseDouble(data[2])-Double.parseDouble(data[3]);
String[] words = data[4].split(" ");
for(String w:words)
{
String[] w_n = w.split("#");
w_n[0] += "#"+data[0];
int index = Integer.parseInt(w_n[1])-1;
if(_temp.containsKey(w_n[0]))
{
Vector<Double> v = _temp.get(w_n[0]);
if(index>v.size())
for(int i = v.size();i<index; i++)
v.add(0.0);
v.add(index, score);
_temp.put(w_n[0], v);
}
else
{
Vector<Double> v = new Vector<Double>();
for(int i = 0;i<index; i++)
v.add(0.0);
v.add(index, score);
_temp.put(w_n[0], v);
}
}
}
Set<String> temp = _temp.keySet();
for (Iterator<String> iterator = temp.iterator(); iterator.hasNext();) {
String word = (String) iterator.next();
Vector<Double> v = _temp.get(word);
double score = 0.0;
double sum = 0.0;
for(int i = 0; i < v.size(); i++)
score += ((double)1/(double)(i+1))*v.get(i);
for(int i = 1; i<=v.size(); i++)
sum += (double)1/(double)i;
score /= sum;
String sent = "";
if(score>=0.75)
sent = "strong_positive";
else
if(score > 0.25 && score<=0.5)
sent = "positive";
else
if(score > 0 && score>=0.25)
sent = "weak_positive";
else
if(score < 0 && score>=-0.25)
sent = "weak_negative";
else
if(score < -0.25 && score>=-0.5)
sent = "negative";
else
if(score<=-0.75)
sent = "strong_negative";
_dict.put(word, sent);
}
}
catch(Exception e){e.printStackTrace();}
}
public String extract(String word, String pos)
{
return _dict.get(word+"#"+pos);
}
}

Firstly, how are you running the class. Through command line or within an IDE such as Eclipse.
If you are using a command line you must ensure you classpath has been set properly. If you are unfamiliar with such matters I would encourage creating a java project in an IDE and running it from there as the classpath will be configured for you. Creating your first Java project