Class LoadImageTask

java.lang.Object

javax.swing.SwingWorker<BufferedImage, Void>

org.jdesktop.application.Task<BufferedImage, Void>

examples.LoadImageTask

All Implemented Interfaces:

Runnable, Future<BufferedImage>, RunnableFuture<BufferedImage>

public class LoadImageTask
extends Task<BufferedImage, Void>

A Task that loads an image from a URL. Loading and decoding progress is reported via the Task progress property and messages are generated when the Task begins and when it finishes. If errors occur then warnings are logged and the Task's value is null.

Applications would typically use LoadImageTask by creating a private subclass that overrode the done method. See SingleFrameExample5.java for an example.

Resources for this class are in the resources/LoadImageTask.properties ResourceBundle.

Nested Class Summary

Nested classes/interfaces inherited from class Task

Task.BlockingScope, Task.InputBlocker

Nested classes/interfaces inherited from class SwingWorker

SwingWorker.StateValue

Nested classes/interfaces inherited from interface Future

Future.State

Constructor Summary

Constructors

Constructor	Description
LoadImageTask(Application app, URL url)

Method Summary

Modifier and Type	Method	Description
protected void	cancelled()	Called when this Task has been cancelled by SwingWorker.cancel(boolean).
protected BufferedImage	doInBackground()
protected void	failed(Throwable e)	Called when an execution of this Task fails and an ExecutionExecption is thrown by get.
protected void	finished()	Called unconditionally (in a finally clause) after one of the completion methods, succeeded, failed, cancelled, or interrupted, runs.
protected final URL	getImageURL()
protected void	interrupted(InterruptedException e)	Called if the Task's Thread is interrupted but not explicitly cancelled.
protected void	succeeded(BufferedImage image)	Called when this Task has successfully completed, i.e.

Methods inherited from class Task

addTaskListener, done, getApplication, getContext, getDescription, getExecutionDuration, getInputBlocker, getMessage, getMessageDuration, getResourceMap, getTaskListeners, getTaskService, getTitle, getUserCanCancel, isPending, isProgressPropertyValid, isStarted, message, process, removeTaskListener, resourceName, setDescription, setInputBlocker, setMessage, setProgress, setProgress, setProgress, setTitle, setUserCanCancel

Methods inherited from class SwingWorker

addPropertyChangeListener, cancel, execute, firePropertyChange, get, get, getProgress, getPropertyChangeSupport, getState, isCancelled, isDone, publish, removePropertyChangeListener, run, setProgress

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface Future

exceptionNow, resultNow, state

Constructor Details

LoadImageTask

public LoadImageTask(Application app,
 URL url)

Method Details

getImageURL

protected final URL getImageURL()

doInBackground

protected BufferedImage doInBackground()

Specified by:

doInBackground in class SwingWorker<BufferedImage, Void>

cancelled

protected void cancelled()

Description copied from class: Task

Called when this Task has been cancelled by SwingWorker.cancel(boolean).

This method runs on the EDT. It does nothing by default.

Overrides:

cancelled in class Task<BufferedImage, Void>

See Also:

• Task.done()

interrupted

protected void interrupted(InterruptedException e)

Description copied from class: Task

Called if the Task's Thread is interrupted but not explicitly cancelled.

This method runs on the EDT. It does nothing by default.

Overrides:

interrupted in class Task<BufferedImage, Void>

Parameters:

e - the InterruptedException thrown by get

See Also:

• SwingWorker.cancel(boolean)
• Task.done()
• SwingWorker.get()

succeeded

protected void succeeded(BufferedImage image)

Description copied from class: Task

Called when this Task has successfully completed, i.e. when its get method returns a value. Tasks that compute a value should override this method.

This method runs on the EDT. It does nothing by default.

Overrides:

succeeded in class Task<BufferedImage, Void>

Parameters:

image - the value returned by the get method

See Also:

• Task.done()
• SwingWorker.get()
• Task.failed(Throwable)

failed

protected void failed(Throwable e)

Description copied from class: Task

Called when an execution of this Task fails and an ExecutionExecption is thrown by get.

This method runs on the EDT. It Logs an error message by default.

Overrides:

failed in class Task<BufferedImage, Void>

Parameters:

e - the cause of the ExecutionException

See Also:

• Task.done()
• SwingWorker.get()
• Task.failed(Throwable)

finished

protected void finished()

Description copied from class: Task

Called unconditionally (in a finally clause) after one of the completion methods, succeeded, failed, cancelled, or interrupted, runs. Subclasses can override this method to cleanup before the done method returns.

This method runs on the EDT. It does nothing by default.

Overrides:

finished in class Task<BufferedImage, Void>

See Also:

• Task.done()
• SwingWorker.get()
• Task.failed(Throwable)