In C# there is a method to write a string to the Console.
it is Console.WriteLine("Hello {0} My name is {1}", "World", "John");
this would return
Hello World My name is John
How can i recreate such a method structure in java. So that i can pass in unlimited amount of the parameters in the end of my method and get it placed in the right indexes?
Any help would be greatly appreciated
// EDIT
Maybe i have not explained well enough. I do not need the method to make a console output. I just want to know how can i recreate a structure in which i can pass as many parameters as i want and get it placed in the right place. For example
movie.setPlot("This movie is {0} and gets a rating of {1}", "FUN", "6 Thumbs up");
which would set the the plot varialbe for a movie to
This movie is FUN and gets a rating of 6 Thumbs up
// EDIT 2
End Result:
private static final String PREFIX = "AwesomeApp";
public static void e(String TAG, String msg){
android.util.Log.e(PREFIX + " >> " +TAG, msg);
}
public static void e(String TAG, String msg, Object...args){
e(TAG, String.format(msg, args));
}
You can use var-args to handle an indeterminate number of parameters:
void setPlot(String text, String... args) {
System.out.printf(text, args);
}
You can use the Formatter class introduced in Java 5, like this:
Formatter f = new Formatter();
f.format("Hello %s my name is %s", "World", "John");
System.out.println(f.toString());
Edit: (in response to the edit of the question) You can use a formatter in the implementation of your own custom method, like this:
private String plot;
void setPlot(String formatStr, Object... data) {
Formatter f = new Formatter();
format(formatStr, data);
plot = f.toString();
}
You can now call your setPlot function like this:
movie.setPlot("This movie is %s and gets a rating of %s", "FUN", "6 Thumbs up");
Related
public class SimpleDialogueBox {
public static void main(String[] args){
String name = JOptionPane.showInputDialog("Name");
String age = JOptionPane.showInputDialog("age");
String address = JOptionPane.showInputDialog("Address");
String contact = JOptionPane.showInputDialog("Contact Number");
JOptionPane.showMessageDialog(null, "User information is", name);
}
}
I want to have a display like this:
Explanation
The method JOptionPane#showMessageDialog takes a regular object to display, a String for example, nothing fancy. From its documentation:
public static void showMessageDialog​(Component parentComponent, Object message) throws HeadlessException
Brings up an information-message dialog titled "Message".
Parameters:
parentComponent - determines the Frame in which the dialog is displayed; if null, or if the parentComponent has no Frame, a default Frame is used
message - the Object to display
So you just have to build the String you want to display and then you pass it to the method. You can concatenate Strings using the + operator:
String lineSep = System.lineSeparator();
String message = "User information is: " + name + lineSep;
And so on. You can also use a StringBuilder for this purpose, it is also more efficient to use it for various reasons.
Code
Here is the full code:
String name = JOptionPane.showInputDialog("Name");
String age = JOptionPane.showInputDialog("age");
String address = JOptionPane.showInputDialog("Address");
String contact = JOptionPane.showInputDialog("Contact Number");
String lineSep = System.lineSeparator();
StringBuilder result = new StringBuilder();
result.append("User information is: ").append(lineSep).append(lineSep);
result.append("Name: ").append(name).append(lineSep);
result.append("Age: ").append(age).append(lineSep);
result.append("Address: ").append(address).append(lineSep);
result.append("Contact Number: ").append(contact);
JOptionPane.showMessageDialog(null, result.toString());
And that is the resulting dialog:
I am working on a Spring Shell project. The tool is a command line tool to manipulate data in a database. There are commands like add user (which adds a record to a table in database). In order to execute any commands the user of the tool has to be connected to the database. I would like to be able to run this all in one line. The user of my tool should be able to write a command like the following.
--database connection string xyz --username abc --password mno add user --username bob --role AA_ADMIN --company Microsoft
Here the three parameters database connection string, username and password are required to run the add user command.
Below I have included some sample code it is from the spring shell reference docs
package commands;
import org.springframework.shell.core.CommandMarker;
import org.springframework.shell.core.annotation.CliAvailabilityIndicator;
import org.springframework.shell.core.annotation.CliCommand;
import org.springframework.shell.core.annotation.CliOption;
import org.springframework.stereotype.Component;
#Component
public class UserManipulation implements CommandMarker {
private boolean simpleCommandExecuted = false;
#CliAvailabilityIndicator({"hw simple"})
public boolean isSimpleAvailable() {
//always available
return true;
}
#CliAvailabilityIndicator({"hw complex", "hw enum"})
public boolean isComplexAvailable() {
if (simpleCommandExecuted) {
return true;
} else {
return false;
}
}
#CliCommand(value = "hw simple", help = "Print a simple hello world message")
public String simple(
#CliOption(key = { "message" }, mandatory = true, help = "The hello world message") final String message,
#CliOption(key = { "location" }, mandatory = false, help = "Where you are saying hello", specifiedDefaultValue="At work") final String location) {
simpleCommandExecuted = true;
return "Message = [" + message + "] Location = [" + location + "]";
}
#CliCommand(value = "hw complex", help = "Print a complex hello world message")
public String hello(
#CliOption(key = { "message" }, mandatory = true, help = "The hello world message") final String message,
#CliOption(key = { "name1"}, mandatory = true, help = "Say hello to the first name") final String name1,
#CliOption(key = { "name2" }, mandatory = true, help = "Say hello to a second name") final String name2,
#CliOption(key = { "time" }, mandatory = false, specifiedDefaultValue="now", help = "When you are saying hello") final String time,
#CliOption(key = { "location" }, mandatory = false, help = "Where you are saying hello") final String location) {
return "Hello " + name1 + " and " + name2 + ". Your special message is " + message + ". time=[" + time + "] location=[" + location + "]";
}
#CliCommand(value = "hw enum", help = "Print a simple hello world message from an enumerated value")
public String eenum(
#CliOption(key = { "message" }, mandatory = true, help = "The hello world message") final MessageType message){
return "Hello. Your special enumerated message is " + message;
}
enum MessageType {
Type1("type1"),
Type2("type2"),
Type3("type3");
private String type;
private MessageType(String type){
this.type = type;
}
public String getType(){
return type;
}
}
}
So currently, hw simple is a command that is required to be executed before running hw complex or hw enum command. I do not want hw simple to be a command instead it the message parameter within the hw simple command should be a parameter that is required as a prerequisite to run hw complex or hw enum. So for example the command that I would like to run is.
--message hw complex --message abc --name1 def --name2 ghi --time 7:98 --location: Seattle
Does anyone know how to do this? If it is not possible to do this I would like to hear that or any alternative ideas if possible.
You have 2 options here:
either make those 3 additional parameters (database, username, password) parameters of each and every command that require them (note that in your particular example, you would need to rename one of those username parameters [the one to connect to the DB, or the one that represents the user to add] as you can't have 2 parameters with the same name obviously).
Use the #CliAvailabilityIndicator approach, similar to what is described in the example, where a first command (maybe named use or connect) first tests the connection with the 3 given parameters and stores them somewhere, so that any further "real" command (such as add user) can use those values.
Also note that you can actually use a combination of the two (i.e. use solution 2 to provide defaults, that may be overridden on a case by case basis by solution 1).
Lastly, please note that you'll never be able to have something like what you describe at the beginning of your question, as command names must be at the beginning and they can't contain -- (options do)
I am have trouble creating an array or object(with multiple fields) and sending it to an array-list. Any help would be greatly appreciated. I have spent hours looking through every video on YouTube with the words object and array-list in them and have been unable to find much help.
The program needs to prompt the user to pick a option (1. AddItem) then prompt the user for the name and format (dvd, vhs) and save multiple objects with these variables in an array-list. I either keep having the location where it is saved in memory returned to me or instead of multiple objects one large object is created.
Library:
import java.util.Scanner;
import java.util.ArrayList;
public class Library {
static ArrayList<Object> items = new ArrayList<Object>();
static int menuOption;
static Scanner scan = new Scanner(System.in);
public static void main(String args[]) {
String title, format;
boolean right = false;
do{
displayMenu();
if (menuOption == 1){
System.out.println("Enter Title: ");
title = scan.next();
System.out.println("Enter format: ");
format = scan.next();
addNewItem(title, format);
} else {System.out.println(items);
}
} while (!right);
}
static int displayMenu(){
System.out.println("Menu: ");
System.out.println("1. Add New Item");
menuOption = scan.nextInt();
return menuOption;
}
static void addNewItem(String title, String format){
MediaItem b = new MediaItem();
b.setTitle(title);
b.setFormat(format);
items.add(b);
}
}
MediaItem:
public class MediaItem {
String title;
String format;
MediaItem(){
title = null;
format = null
}
MediaItem(String title, String format){
title = new String();
format = new String();
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getFormat() {
return format;
}
public void setFormat(String format) {
this.format = format;
}
}
The program will run if you:
1 - Change the line
static ArrayList<Object> items = new ArrayList<Object>();
to
static ArrayList<MediaItem> items = new ArrayList<MediaItem>();
2 - Change the line
System.out.println( items );
to
for ( MediaItem mi : items )
{
System.out.println( mi.getTitle() + ", " + mi.getFormat() );
}
3 - Insert a ";" at the end of the line
format = null
I did it here and it worked.
I either keep having the location where it is saved in memory returned to me
I am guessing you ran into this when you tried to either use System.out.println() to print a MediaItem, or you otherwise tried to automatically convert an object to a string. Whatever approach you took when you were seeing the memory addresses is probably the right way to do it, your problem was only in your displaying of the data.
Consider:
MediaItem item = ...;
System.out.println(item);
By default, Java doesn't know how to convert arbitrary objects to strings when you do stuff like that, and so it just spits out the class name and memory address. You either need to print the fields separately (e.g. Java knows how to display a String already), like:
System.out.println("Title: " + item.getTitle() + " Format: " + item.getFormat());
Or you can override toString() (declared in Object) to provide a custom string conversion:
class MediaItem {
...
#Override public String toString () {
return "Title: " + title + " Format: " + format;
}
}
And then you can print it directly:
System.out.println(item);
It is the default base implementation of Object.toString() that produces those strings with the memory address in them.
Based on your description, I'm guessing you had a roughly working implementation but ran into this issue and ended up changing around (and breaking) a bunch of other unrelated things to try and fix it.
So I'm working on a program to interface with a file based database. Mostly I'm trying to figure out how to work with it so that I can make objects and store their information in the database so that I can pull the data later.
IE Object Taylor
Name = Taylor
Age = 20
School = Whatever
So that I can get back on and call that information up when queried.
This is an example of an object I want to store. I may be doing this part wrong.
package com.catalyse.db;
public class Taylor implements java.io.Serializable
{
public String name = "Taylor M May";
public int age = 20;
public String school = "UC Boulder";
}
The DB structure I'm using is based on RandomAccessFile and I didn't make it, I'm just trying to figure out how to implement it.
package com.catalyse.db;
import java.util.*;
import java.util.Scanner;
/**
* Simple test class for the RecordsFile example. To run the test,
* set you CLASSPATH and then type "java hamner.dbtest.TestRecords"
*/
public class Run {
static void log(String s) {
System.out.println(s);
}
private static String name()
{
Scanner name = new Scanner(System.in);
String name1 = name.next();
return name1;
}
public static void main (String[] args) throws Exception {
System.out.println(new Date());
Scanner SC = new Scanner(System.in);
log("What would you like to name the database?");
String filename = SC.next();
log("creating records file...");
RecordsFile recordsFile = new RecordsFile(filename+".records", 64);
log("adding a record...");
RecordWriter rw = new RecordWriter("foo.username");
rw.writeObject(new Taylor());
recordsFile.insertRecord(rw);
log("reading record...");
RecordReader rr = recordsFile.readRecord("foo.username");
Taylor name = (Taylor)rr.readObject();
System.out.println("\tlast access was at: " + name.toString());
log("test completed.");
}
}
And here is what I get back from it,
Wed Nov 20 11:56:04 MST 2013
What would you like to name the database?
save3
creating records file...
adding a record...
reading record...
last access was at: com.catalyse.db.Taylor#50aed564
test completed.
My problem is that I want it to return information about the class, not just its name and location in the DB.
You need to override the toString method.
public String toString()
{
StringBuilder sb = new StringBuilder();
sb.append("Name: ");
sb.append(this.name);
//rest of fields
return sb.toString();
}
As a matter of clarity, you are not returning its location in the database. You are getting back the object hashValue + the class name.
At this point
Taylor name = (Taylor)rr.readObject();
You can access whatever information you like in the object, e.g.
Taylor name = (Taylor)rr.readObject();
System.out.println(name.age + ", " + name.name + ", " + name.school);
Alternatively, just add a
public String toString()
{
return name + ", " + age + ", " + school;
}
method in Taylor and then output it like so
Taylor name = (Taylor)rr.readObject();
System.out.println(name);
Now, concerning...
System.out.println("\tlast access was at: " + name.toString());
name.toString() isn't really required. If you append an object to a String then it automatically calls that objects toString() method to get a value.
Lastly, I'd like to note that generally we don't access object members like name, school and age by just accessing them. We generally make them private members then add methods to get and set them, so that we control and can track how they are manipulated.
Hello i am new to this forum. I am fairly new to Java. I am trying to convert USA to UK words so that when i input a sentence containing any of the USA words, the output will be will be the sentence but replaced with UK words. This is my attempt:
import javax.swing.JOptionPane;
public class PArraystest
{
public static void main(String [] arg)
{
String[] wordUSA = {"Cell", "Elevator", "Fries", "Gasoline", "Faucet"};
String[] wordUK = {"Mobile", "Lift", "Chips", "Petrol", "Tap"};
String changeUK = "";
String sent;
sent = JOptionPane.showInputDialog("What name do you want to search for?");
for (int i = 0; i < wordUSA.length; i++)
{
if (sent.contains(wordUSA[i]))
{
sent.replace((wordUK)[i],(wordUSA)[i]);
//break;
}
}
//if (changeUK.equals(""))
//System.out.println(" was not found.");
//else
System.out.println(sent);
}
}
Two things:
You need to use assign the string returned from replace to sent again, or sent will be unchanged`.
The replace method is public String replace(char oldChar, char newChar), so the oldChar US word should come first, followed by the UK word.
This is the correct line: sent = sent.replace(wordUSA[i],wordUK[i]);
The replace method returns a new String with the replaced text:
//sent.replace((wordUK)[i],(wordUSA)[i]);
sent = sent.replace((wordUK)[i],(wordUSA)[i]);
Two problems:
First, you should assign the replaced string back to sent.
Second, you should use replaceAll instead of replace.
There's a whole framework of functionality devoted to this in Java called internationalizaion (i18n)
While the sample below is primarily for generation origianlly I thought I'd point it out because you could probably devise how to run it in reverse as well.
Here's a snippet that shows the proper way to go about this:
http://docs.oracle.com/javase/tutorial/i18n/intro/after.html
(all code below is theirs and not my own)
Note that to run this you'll need the resource files from the site or the versions I have provided below from the site
import java.util.*;
public class I18NSample {
static public void main(String[] args) {
String language;
String country;
if (args.length != 2) {
language = new String("en");
country = new String("US");
} else {
language = new String(args[0]);
country = new String(args[1]);
}
Locale currentLocale;
ResourceBundle messages;
currentLocale = new Locale(language, country);
messages = ResourceBundle.getBundle("MessagesBundle", currentLocale);
System.out.println(messages.getString("greetings"));
System.out.println(messages.getString("inquiry"));
System.out.println(messages.getString("farewell"));
}
}
MessagesBundle.properties:
greetings = Hello.
farewell = Goodbye.
inquiry = How are you?
MessagesBundle_en_US.properties:
greetings = Hello.
farewell = Goodbye.
inquiry = How are you?
MessagesBundle_fr_FR.properties:
greetings = Bonjour.
farewell = Au revoir.
inquiry = Comment allez-vous?