foxtrot

Class Task

java.lang.Object

foxtrot.Task

Direct Known Subclasses:

AsyncTask, Job

public abstract class Task
extends java.lang.Object

A time-consuming task to be executed in the Worker Thread that may throw checked exceptions.
Users must implement the run() method with the time-consuming code, and not worry about exceptions, for example:

 Task task = new Task()
 {
     public Object run() throws InterruptedException
     {
        Thread.sleep(10000);
        return null;
     }
 };
 

Exceptions and Errors thrown by the run() method will be rethrown automatically by Worker.post(Task) or by ConcurrentWorker.post(Task)

Version:

$Revision: 1.13 $

See Also:

Worker, ConcurrentWorker

Field Summary

Fields

Modifier and Type	Field and Description
private boolean	completed
private java.lang.Object	result
private java.security.AccessControlContext	securityContext
private java.lang.Throwable	throwable

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Task() Creates a new Task.

Method Summary

Methods

Modifier and Type	Method and Description
private java.lang.Object	getResult() Returns the result of this Task operation, as set by setResult(java.lang.Object).
protected java.lang.Object	getResultOrThrow() Returns the result of this Task operation, as set by setResult(java.lang.Object).
(package private) java.security.AccessControlContext	getSecurityContext() Returns the protection domain stack at the moment of instantiation of this Task.
(package private) java.lang.Throwable	getThrowable() Returns the throwable as set by setThrowable(java.lang.Throwable).
boolean	isCompleted() Returns whether the execution of this Task has been completed or not.
(package private) void	postRun() Callback invoked from the worker thread to perform some operation just after the Task has been completed.
(package private) void	reset() Resets the internal status of this Task, that can be therefore be reused.
abstract java.lang.Object	run() The method to implement with time-consuming code.
(package private) void	setCompleted(boolean value) Sets the completion status of this Task.
(package private) void	setResult(java.lang.Object result) Sets the result of this Task operation, as returned by the run() method.
(package private) void	setThrowable(java.lang.Throwable x) Sets the throwable eventually thrown by the run() method.

Methods inherited from class java.lang.Object

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

Field Detail

result

private java.lang.Object result

throwable

private java.lang.Throwable throwable

completed

private boolean completed

securityContext

private java.security.AccessControlContext securityContext

Constructor Detail

Task

protected Task()

Creates a new Task.

Method Detail

run

public abstract java.lang.Object run()
                              throws java.lang.Exception

The method to implement with time-consuming code. It should NOT be synchronized or synchronize on this Task instance, otherwise the AWT Event Dispatch Thread cannot efficiently test when this Task is completed.

Throws:

java.lang.Exception

getResultOrThrow

protected final java.lang.Object getResultOrThrow()
                                           throws java.lang.Exception

Returns the result of this Task operation, as set by setResult(java.lang.Object). If an exception or an error is thrown by run(), it is rethrown here. Synchronized since the variables are accessed from 2 threads Accessed from the AWT Event Dispatch Thread.

Throws:

java.lang.Exception

See Also:

setResult(java.lang.Object), setThrowable(java.lang.Throwable)

getResult

private final java.lang.Object getResult()

Returns the result of this Task operation, as set by setResult(java.lang.Object). Synchronized since the variable is accessed from 2 threads Accessed from the AWT Event Dispatch Thread.

See Also:

getResultOrThrow()

setResult

final void setResult(java.lang.Object result)

Sets the result of this Task operation, as returned by the run() method. Synchronized since the variable is accessed from 2 threads Accessed from the worker thread. Package protected, used by AbstractWorkerThread

See Also:

getResultOrThrow(), getResult()

getThrowable

final java.lang.Throwable getThrowable()

Returns the throwable as set by setThrowable(java.lang.Throwable). Synchronized since the variable is accessed from 2 threads Accessed from the AWT Event Dispatch Thread.

setThrowable

final void setThrowable(java.lang.Throwable x)

Sets the throwable eventually thrown by the run() method. Synchronized since the variable is accessed from 2 threads Accessed from the worker thread. Package protected, used by AbstractWorkerThread

See Also:

getThrowable()

isCompleted

public final boolean isCompleted()

Returns whether the execution of this Task has been completed or not.

setCompleted

final void setCompleted(boolean value)

Sets the completion status of this Task. Synchronized since the variable is accessed from 2 threads. Accessed from the worker thread and from the AWT Event Dispatch Thread. Package protected, used by AbstractWorkerThread

See Also:

isCompleted()

getSecurityContext

final java.security.AccessControlContext getSecurityContext()

Returns the protection domain stack at the moment of instantiation of this Task. Synchronized since the variable is accessed from 2 threads Accessed from the worker thread. Package protected, used by AbstractWorkerThread

See Also:

Task()

reset

final void reset()

Resets the internal status of this Task, that can be therefore be reused. Synchronized since the variables are accessed from 2 threads Accessed from the AWT Event Dispatch Thread. Package protected, used by Worker

See Also:

isCompleted()

postRun

void postRun()

Callback invoked from the worker thread to perform some operation just after the Task has been completed.