oracle.adf.share.sandbox.util

Class SandboxBackgroundTask<T>

java.lang.Object

oracle.adf.share.sandbox.util.SandboxBackgroundTask<T>

Type Parameters:

T - the type of the task result

Direct Known Subclasses:

SandboxBackgroundTask.SimpleTask

public class SandboxBackgroundTask<T>
extends java.lang.Object

A SandboxBackgroundTask allows a sandbox related task to be performed in the background using a SandboxWorker object. Part of the task may be performed in the current thread first before the rest of the task is performed in the background thread. Subclasses may override the "fixture methods" to execute custom code before or after the task, or when an exception is thrown.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	SandboxBackgroundTask.Job<R> A part of the task.
static class	SandboxBackgroundTask.Proxy<R> An object that performs a task using a SandboxBackgroundTask object.
static class	SandboxBackgroundTask.SimpleProxy<R> A simple proxy that allows clients to wait for the task result.
static class	SandboxBackgroundTask.SimpleTask<R> A task created by SimpleProxy.

Field Summary

Fields

Modifier and Type	Field and Description
protected SandboxBackgroundTask.Job<T>	backgroundJob The job that runs in a background thread.
protected SandboxBackgroundTask.Job<java.lang.Object>	foregroundJob The job that runs in the current thread, may be null.

Constructor Summary

Constructors

Constructor and Description
SandboxBackgroundTask(SandboxBackgroundTask.Job<java.lang.Object> foregroundJob, SandboxBackgroundTask.Job<T> backgroundJob) Creates a task.
SandboxBackgroundTask(SandboxBackgroundTask.Job<T> backgroundJob) Creates a task that is performed entirely in a background thread.

Method Summary

Modifier and Type	Method and Description
protected void	catchBlock(java.lang.Exception e) Invoked when a foreground job or background job throws an exception, or when tryBlockInitialization or tryBlockFinalization throws an exception.
protected void	catchBlock(java.lang.Throwable e) Invoked when a foreground job or background job throws an error, or when tryBlockInitialization or tryBlockFinalization throws an error.
protected void	finallyBlock() Invoked after an exception is thrown, or after tryBlockFinalization completes without any exception.
protected <X> SandboxWorker<X>	newSandboxWorker(java.util.concurrent.Callable<X> job) Creates a SandboxWorker object to run the background job.
void	perform() Performs this task.
void	perform(long bgTimeout, java.util.concurrent.TimeUnit unit) Performs this task.
protected void	tryBlockFinalization(T result) Invoked in a background thread after the task is performed.
protected void	tryBlockInitialization() Invoked before a task is performed.
protected void	unhandledThrowable(java.lang.Throwable t) Invoked when catchBlock or finallyBlock throws an exception.

Methods inherited from class java.lang.Object

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

Field Detail

foregroundJob

protected final SandboxBackgroundTask.Job<java.lang.Object> foregroundJob

The job that runs in the current thread, may be null.

backgroundJob

protected final SandboxBackgroundTask.Job<T> backgroundJob

The job that runs in a background thread.

Constructor Detail

SandboxBackgroundTask

public SandboxBackgroundTask(SandboxBackgroundTask.Job<java.lang.Object> foregroundJob,
                             SandboxBackgroundTask.Job<T> backgroundJob)

Creates a task.

Parameters:

foregroundJob - the job that runs in the current thread; null if the whole task is to be performed in the background. If specified, the input to the foreground job is always null. The output of the foreground job is passed into the background job as the input. The background job must complete the task and return the task result.

backgroundJob - the job that runs in a background thread

Throws:

java.lang.IllegalArgumentException - if the background job is null

SandboxBackgroundTask

public SandboxBackgroundTask(SandboxBackgroundTask.Job<T> backgroundJob)

Creates a task that is performed entirely in a background thread.

Parameters:

backgroundJob - the job that runs in a background thread

Throws:

java.lang.IllegalArgumentException - if the given argument is null

Method Detail

perform

public final void perform()

Performs this task. If a foreground job is specified, the foreground job is performed first in the current thread, which will be blocked until the foreground job is done. This method then returns immmediately after the background job starts in a background thread.

Note that any java.lang.Throwable thrown by the jobs will not be re-thrown by this method. java.lang.Exception objects should be handled by catchBlock(Exception) and everything else by unhandledThrowable(Throwable).

perform

public final void perform(long bgTimeout,
                          java.util.concurrent.TimeUnit unit)
                   throws java.lang.InterruptedException,
                          java.util.concurrent.TimeoutException

Performs this task. If a foreground job is specified, the foreground job is performed first in the current thread, which will be blocked until the foreground job is done. This method then waits for the background job to finish for up to the specified wait time. TimeoutException is thrown if the background job is still not done when the wait timed out.

Note that any java.lang.Throwable thrown by the jobs will not be re-thrown by this method. java.lang.Exception objects should be handled by catchBlock(Exception) and everything else by unhandledThrowable(Throwable).

Parameters:

bgTimeout - the maximum time to wait