Swing/AWT/SWT :: Using Multiple SwingWorker Threads
Aug 23, 2014
I have a Swing UI in which on click of Search button, I trigger the Search in 6 different modules in 6 Swing Worker threads. The results are returned by each Swing Worker class to the calling class.
I tried to use the below code to get the values returned from each thread. Now, I want to continue further only after all threads finish their execution. How to achieve this?
thread1.addPropertyChangeListener(new PropertyChangeListener() {
public void propertyChange(PropertyChangeEvent evt) {
if (StateValue.DONE == thread1.getState()) {
try {
[Code] ....
I got several examples where the UI is updated direstly from multiple threads. I want the values to be returned to calling class because of below reasons:
1) When even one worker thread fails for some reason, I dont want to show the any result in the UI
2) Earlier, I was updating the UI in done() of every worker class. But, UI became inconsistent. E.g When one thread is in progress, other threads were completed and updating the UI which I dont want to do.
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Sep 26, 2014
Why this code is not working/my JTable won't updated after i click the button
import java.awt.Component;
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.Connection;
import java.sql.ResultSet;
[code]....
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Oct 8, 2014
I am writing a program that solves sudoku puzzles. It has a Swing GUI with a "solve" button. I have written an actionListener class with an actionPerformed method that is invoked when the user presses this button. It is the following:
public void actionPerformed(ActionEvent event) {
try {
worker = new SudokuSolveWorker();
worker.addPropertyChangeListener(this);
worker.execute();
SolveFrame sf = new SolveFrame();
} catch (Exception exc) {
System.out.println(exc.getMessage());
exc.printStackTrace();
}
}
The code creates a worker, a new instance of SudokuSolveWorker. The worker.execute() statement causes the doInBackground() method of this class to be called. This solves the Sudoku. A property change listener "picks up" the result:
public void propertyChange(PropertyChangeEvent event) {
try {
System.out.println("" + javax.swing.SwingUtilities.isEventDispatchThread());
SudokuModel solvedModel = (SudokuModel) worker.get();
} catch (Exception exc) {
System.out.println(exc.getMessage());
exc.printStackTrace();
}
}
As I wrote, this works without freezing up the user interface in the sense that the program seems unstable. However, the user interface does not respond to "commands" (mouse clicks) anymore until the worker thread has finished.
In the first code fragment I create an instance of SolveFrame which is an extension of a JFrame. It is a simple frame with a "cancel" button. It is drawn on the screen, even though it is called after the worker.execute() statement. I'd like the user to be able to click this "cancel" button, after which the solving of the sudoku puzzle should be stopped. However, since the program does not respond to mouse clicks anymore, the "cancel" button cannot be pressed.
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May 21, 2014
My multi threaded application processes and loads records into an ECM repository. For reconcliation purposes , I am trying to build an XML format report with the results of the processing per record, while processing is underway per thread. The method below is called from every thread wvery time its ready to append an element to the DOM with the status.
public void writeReportLine(Element rptLine) {
// Write output to report file
synchronized (XMLReportHandler.class) {
reportOutput.getDocumentElement().appendChild(rptLine);
}
}
After all processing completes, the below method is called only once by every thread to write to the File on the file system:
public void writeToReportFile() {
synchronized (XMLReportHandler.class) {
try{
//write the content into xml file
TransformerFactory transformerFactory = TransformerFactory.newInstance();
Transformer transformer = transformerFactory.newTransformer();
DOMSource source = new DOMSource(reportOutput);
[Code] ....
The problem is that when under load, the threads just seem to hang while the transformer.transform(source, result) call keeps getting executed until there is an interrupt of some sort. I was able to examine a section of what was appended and it was status for records that had finished processing very early in the process based on my application logs. Once an interrupt is recieved , it looks like the threads recover.
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Apr 18, 2014
Actually, i want to create multiple ball using multithreading.I have created a class 'CreateBall' and this class is making ball and second class 'Balls' is a Panel where the ball is display.But only one ball is being displayed.
Here is my code.......
CreateBall.java
import java.awt.*;
public class CreateBall implements Runnable
{
int px,py;
int w=20,h=20;
Graphics g;
public CreateBall(int px,int py)
[Code] .....
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Jun 19, 2014
I am very new to threading. I have a program that calls my api and gets data back in json format. Each request returns a row of data in json format. All together I need to retrieve about 2,000,000 rows a day which means 2,000,000 requests (I understand that this is bad design, but the system was not designed for this purpose it is just what I need to do for the next couple of weeks). When I tried running it on a single thread I was processing about 200 requests a minute which is much too slow. As a result I created 12 threads and I was processing 5500 rows a minutes which was a great improvement.
The problem was only about on average 90% of the rows were inserted into the database as I ran it a few times to make sure. Before each insert printed to a file each URL which was sent and then I checked to see if each insert statement was successful (returned 1 when executed ) and it all seems fine. Every time I run it it inserts about 90% but it does varies and it has never been a consistent number.
Essentially the code starts in main by creating 12 threads. Each thread's creates a run method which calls a new instance of MySQLPopulateHistData and passes a start and end integer which are used in the insert statement for ranges. I have done many system.out.println type testing and can see all the threads do start and all the 12 instances (one instance for each thread) called are executing?
MAIN:
import java.io.IOException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class MainClass {
public static void main(String[] args) {
[code]....
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Jun 30, 2014
I have a multithreaded application. I have a Logger class with static methods that I use across threads. Would it behoove me to add the synchronized keyword to the static methods of the Logger class since I use this class statically in different threads?
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Feb 5, 2014
Can you have multiple key events? by that I mean say you press the right arrow key, or a number on the numeric pad, then you press the letter c. does the second key event get fired? and i can catch both events?
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May 27, 2014
I've been doing a course with a heavy focus on applets and AWT using BlueJ. I've branched out and learn to convert my applets to applications. I can successfully use frames to do similar things to applets (in BlueJ's applet viewer) but I can not seem to run more than application at a time (unlike applets where I could run several at the same time).
Below is a simple Hello World program I wrote. When I re-run main() it closes the original and starts again. (I'm aiming to explore the java.net.* libraries and for testing would like to use more than one frame at a time which can communicate to each over via sockets).
import java.awt.*;
import java.awt.event.*;
public class HelloWorld extends Frame implements WindowListener {
public static void main (String[] args) {
HelloWorld app = new HelloWorld();
app.setSize(500,500);
[code]....
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Feb 20, 2014
The below program ask the user to enter the value of x 1 , Y 1 and radius in separate boxes , What would look nice is if the user can Enter the Value X ,Y and radius in the same box.
import javax.swing.JOptionPane;
public class C3E29GeometryTwoCircles {
public static void main(String[] args) {
// Ask the user to enter the x1 coordinate.
String strNumber = JOptionPane.showInputDialog("Enter the value of x1 coordinate " );
double x1 = Double.parseDouble(strNumber);
strNumber = JOptionPane.showInputDialog("Enter the value of y1 coordinate " );
double y1 = Double.parseDouble(strNumber);
[code]...
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Oct 25, 2014
So im making a calculator just basic 4 function with a clear button. as i am working into this project i am running into an issue of assigning which click sets what. For instance i click the two button how do i tell it to assign it to firstNum, versus secondNum?
private class theHandler implements ActionListener{
public void actionPerformed(ActionEvent event){
if(event.getSource()==one){
firstNum=1;
}
if(event.getSource()==two){
secondNum =2;
}
if(event.getSource()==three){
secondNum =3;
}
So this for instance allows me to set one to the firstNum and then add it to two or three but im not sure what to do next. I have in my mind i want to do something like make three listener classes, that operate in sequential order like you pick the first numbers, click an operation, and then select the second numbers then hit the operation(equal) button to display answer. Am i on the right track or what?
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Sep 12, 2014
I'm trying to create a Java swing chess application, but would like to divide the GUI part of it into at least two different classes (possibly more later, but I'm not sure yet). Currently I have a mainGUI class and a ChessBoard class, both of which extend JFrame. I want the main GUI class to contain a JPanel which will house several components, including a JPanel originating from the chessboard class that contains the actual board.
Is there any way to do this? I tried just creating a ChessBoard object in my main GUI class and then adding it to the component, but I got an illegal argument exception, because apparently you can't add one JFrame to another. How to do what I'm trying to do, or just how to split GUIs into multiple classes in general?
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Jun 30, 2014
I have to do an assigment using Swing, where I have to make a Board(extends JPanel) and add multiple instances of moving elements to it, with following requirements:
By adding a new object to the Board, the others must not slow down. Also the user interface must not be blocked by the moving objects. So, the movement of the objects must be handled in a separate thread.
and
The application must support adding lots of objects, so it is not okay if every object has its own thread, as this would take too many resources. Design the application in such a way that it uses a constant number of threads, meaning that the number of threads does not grow when adding more objects.
The question is:
How to do this thing with constant number of threads?
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May 3, 2014
I'm having difficulty implementing keyboard and mouse event handlers at the same time for a program designed to notify the user when a key has been pressed or a mouse button clicked.
I can make and understand a program that does one or the other, but when I try to combine them, either the keyboard only or the mouse only works.
here is the code:
import java.awt.Color;
import java.awt.event.KeyListener;
import java.awt.event.KeyEvent;
import javax.swing.JFrame;
import javax.swing.JTextArea;
import java.awt.event.MouseListener;
[Code] ....
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Feb 22, 2014
I have created two classes. The FrameViewer is my driver class, and Circle is my constructor.
The first problem is, the program seems to be creating both circles, but it only displays displaying the last added circle (in this case, circle2).
The second problem is, I want to pass the color I wish to use to the constructor, but I'm having problems figuring out the proper method to do so. In the constructor, I have assigned Color.BLUE as a default. On circle two, I want to override this color choice and assign Color.Orange. I am not having any luck setting this to work either.
import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.Color;
public class FrameViewer {
public static void main(String[] args) {
JFrame frame = new JFrame();
[code]....
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Apr 22, 2013
Code given below does real time validation for 2 JTextFields. While entering some values to txt1 and txt2 enables the save button and removing values from txt2 or txt1 reset the save button to disable. I use Netbeans as IDE.What I want to do is, enable Save button after checking multiple JTextFields for validity. If any of the text fields is empty, btnSave must be disabled.This program gives expected result up to some extent. But there is little issue. After form appears for the first time, When I type something on Textfield1, Save button enables without checking Textfield2. This happens only at the first time.
public class NewJFrame extends javax.swing.JFrame {
private Boolean isValidFromTextField1 = true;
private Boolean isValidFromTextField2 = true;
public NewJFrame() {
initComponents();
btnSave.setEnabled(false);
[code]....
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Mar 29, 2014
I'm struggling with a small project. I have 2 jFrames. The first frame has a button that...
- Display's the second frame containing a progressbar
- Starts a heavy processing thread
I need to update the progressbar on the second jFrame, from a thread started on the first jFrame.
I have 2 problems:
- How do I update the progressbar?
- When the button is clicked, an empty second frame is displayed with no controls. The controls are only rendered/shown, after the large thread process is finished...
I've attached to this post a small screenshot, showing the main idea ...
Source code:
Button action on the first frame:
private void btnGoActionPerformed(java.awt.event.ActionEvent evt) {
Progress progress = new Progress(); // The second frame
progress.setVisible(true);
clsProcess myProcess = new clsProcess(); // The thread process
myProcess.start();
[Code] ....
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Oct 11, 2014
I have a bunch of textboxes in a panel and I wanted to perform the same code when the user clicks into a textbox (select all the text in it). Right now I've started adding a focusgained listener to each textbox like this:
private void textField1FocusGained(java.awt.event.FocusEvent evt) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
textField1.selectAll();
}
});
}
[Code]...
Is there a way I can have one focusgained listener that all the textfields can point to but have it pick the right textfield in the textFieldx.selectAll();?
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Jun 18, 2014
I am making use of NetBeans IDE 8.0 to build a GUI. The idea is that I set multiple values received from textfields to textarea. This will enable me print the work. But ONLY ONE value from textfields is set(appear on textarea); the others do not appear at all. Below is example of what I mean:
String s = jTextField1.getText();
JTextArea1.setText(s);
String x =
jTextField2.getText();
JTextArea1.setText(x);
Only one is being set. The rest are not.
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Jan 15, 2014
My program has the following requirements.
Several kinds of celebration dates are displayed.
Say Marriage, a new baby is born and so on. Such special dates are not fixed to be once or twice.
Such that a person can have a marriage and a new born baby celebration or both. One of my thoughts was to used several (up to 3). JLabels and JDateChoosers, but it is quite limiting.
How should I design such a component so that it can accommodate several major events of life.
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Jul 6, 2014
I know how to do single selection, but I would like to do multiple row selection only by using CTRL + click without the option of dragging the mouse to select rows. So the user would have to hit ctrl + click each time to highlight additional rows.
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Jan 30, 2015
I have the following listener on a tableset of names:
ListSelectionListener singleListener=new ListSelectionListener() {
public void valueChanged(ListSelectionEvent e) {
int row=e.getFirstIndex();
if (row==previousRow) {
row=-1;
[Code] .....
The println shows that getValueIsAdjusting is called 4 times when I click a single selection from the list. Is this normal behavior? If so how do I determine which call to really use. If not, where can I look to see why it is being called 4 times on a single click?
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May 24, 2014
I decided to write a small Java program to experiment around with BorderLayout, because I'm developing a Java game and I need to have 2 objects placed in a single JFrame at the same time, and everyone I asked said I need BorderLayout to do that.Before you answer: Also, is using BorderLayout the best option for adding multiple video game oriented objects such a sprites to a JFrame?
So the Java program I wrote is supposed to place a JButton on the JFrame and ALSO place a graphic component (a rectangle in this case). The problem is, only the button shows up, as can be seen in the image link below: URL....
Here is the code:
**main.java** --> The main method class + JFrame/JPanel/JButton constructor
import java.awt.BorderLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class main {
[code]....
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Apr 20, 2014
I'm new to Java and trying to write code a Java program on Mac OS X using IntelliJ. My program uses the SWT library and contains two class's; the first called "view" and the second called "main". The "view" class defines the SWT objects, extends the "Thread" class and contains a "run" method;
public void run() {
initComponents();
while (!display.isDisposed()) {
if (!display.readAndDispatch()) {
display.sleep();
[code]....
I searched for a solution and saw that I have to use the "-XstartOnFirstThread" parameter to JVM. I'm trying it with no success.
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Apr 28, 2014
I making a program that a client connect to a server, then it's starts changing information throw the socket. The info is String. When connection with one open client everything is working great. The problem starts when I connect 2 or more clients simultaneously.
The server doesn't know how to handle each request so it's send info to both the client info that is wrong. If I run several clients and then execute the last client that opens he will work fine the others will crush. On the server I'm getting connection reset. The problem i believe is with the closing socket and thread holding.
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Dec 8, 2014
I have i am trying to implement tooltip through javascript, like when we click on an image link tooltip should be displayed and it should have close button/ close image to close that tooltip.like the same way i will have multiple images on page, when ever i click on the images all tooltips should be displayed on the page when ever i want to close that then only it should close through close button on tooltip.can we do it through java script or will go for jquery.
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