jadex.commons.concurrent

Class Executor

java.lang.Object

jadex.commons.concurrent.Executor

All Implemented Interfaces:

java.lang.Runnable

public class Executor
extends java.lang.Object
implements java.lang.Runnable

A helper class for running a single instance of code using the thread pool. The code to be executed has to be placed in the code() method. Once created, the execute() method may be called as often as desired. When no thread is currently executing the object, a new thread is used from the thread pool. Otherwise, the already existing thread continues execution. After shutdown() is called, the executor stops execution, even when execute() is called afterwards.

Field Summary

Fields

Modifier and Type	Field and Description
protected IExecutable	executable The executable.
static java.lang.ThreadLocal<Executor>	EXECUTOR The executor belonging to a thread.
protected int	exethreadcnt The number of current threads for this executor.
protected java.lang.Object	monitor The monitor to synchronize with at thread start (if any).
protected boolean	running Flag indicating if the thread is running.
protected java.util.List<Future<java.lang.Void>>	shutdownfutures The shutdown futures.
protected java.util.List<java.lang.Object>	switchtos The monitors of blocked threads that need to be reactivated.
protected IThreadPool	threadpool The thread pool.
protected java.util.Map<java.lang.Object,java.lang.Throwable>	throwables The exceptions (if any) to be thrown in threads that need to be reactivated.
protected boolean	wanttorun Flag indicating if the thread wants to run.

Constructor Summary

Constructors

Constructor and Description
Executor(IThreadPool threadpool) Create an executor object.
Executor(IThreadPool threadpool, IExecutable executable) Create an executor object.

Method Summary

Modifier and Type	Method and Description
void	blockThread(java.lang.Object monitor) Adjust to execution of current thread to be blocked.
protected boolean	code() The code to be run.
boolean	execute() Make sure a thread is executing the code.
protected int	getThreadCount() Get the number of threads (running blocked) for this executor.
protected boolean	isRunning() Check if the executor is running.
boolean	isSwitching() Check if the executor wants to switch threads.
void	run() Execute the code.
void	setExecutable(IExecutable executable) Set the executable.
IFuture<java.lang.Void>	shutdown() Shutdown the executor.
void	switchThread(java.lang.Object monitor, java.lang.Throwable t) Cease execution of the current thread and switch to another thread waiting for the given monitor.
java.lang.String	toString() String representation.

Methods inherited from class java.lang.Object

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

Field Detail

EXECUTOR

public static final java.lang.ThreadLocal<Executor> EXECUTOR

The executor belonging to a thread.

running

protected boolean running

Flag indicating if the thread is running.

wanttorun

protected boolean wanttorun

Flag indicating if the thread wants to run.

threadpool

protected IThreadPool threadpool

The thread pool.

executable

protected IExecutable executable

The executable.

shutdownfutures

protected java.util.List<Future<java.lang.Void>> shutdownfutures

The shutdown futures.

monitor

protected java.lang.Object monitor

The monitor to synchronize with at thread start (if any).

exethreadcnt

protected int exethreadcnt

The number of current threads for this executor.

switchtos

protected java.util.List<java.lang.Object> switchtos

The monitors of blocked threads that need to be reactivated.

throwables

protected java.util.Map<java.lang.Object,java.lang.Throwable> throwables

The exceptions (if any) to be thrown in threads that need to be reactivated.

Constructor Detail

Executor

public Executor(IThreadPool threadpool)

Create an executor object. Constructor for subclasses overriding the code() method.

Executor

public Executor(IThreadPool threadpool,
                IExecutable executable)

Create an executor object.

Method Detail

run

public void run()

Execute the code.

Specified by:

run in interface java.lang.Runnable

execute

public boolean execute()

Make sure a thread is executing the code.

shutdown

public IFuture<java.lang.Void> shutdown()

Shutdown the executor.

setExecutable

public void setExecutable(IExecutable executable)

Set the executable.

Parameters:

executable - The executable.

code

protected boolean code()

The code to be run.

Returns:

True, when execution should continue.

isRunning

protected boolean isRunning()

Check if the executor is running. Should only be called, when access to executor is correctly synchronized, otherwise inconsistent values might be returned.

getThreadCount

protected int getThreadCount()

Get the number of threads (running blocked) for this executor.

switchThread

public void switchThread(java.lang.Object monitor,
                         java.lang.Throwable t)

Cease execution of the current thread and switch to another thread waiting for the given monitor.

Parameters:

monitor - The monitor to be notified.

t - The exception to be thrown on the unblocked thread (null for continuing normal execution).

blockThread

public void blockThread(java.lang.Object monitor)

Adjust to execution of current thread to be blocked.

toString

public java.lang.String toString()

String representation.

Overrides:

toString in class java.lang.Object

isSwitching

public boolean isSwitching()

Check if the executor wants to switch threads.