de.spieleck.util
Class TaskQueue

java.lang.Object
  de.spieleck.util.TaskQueue

All Implemented Interfaces:

TaskSource

public class TaskQueue

extends java.lang.Object

implements TaskSource

A queue of Tasks (Runnables) for the ThreadPool.

Version:

0.0

Author:

fsn

Field Summary

protected java.lang.Object	cLock Lock for counting
protected boolean	started Did we allready have an assignement?
protected java.util.LinkedList	tasks The queue of Files which need to be processed
protected boolean	workExpected Can we finish now?

Constructor Summary

TaskQueue()
Construct a queue.

Method Summary

void	addTask(java.lang.Runnable r) Add a task to execute
java.lang.Runnable	getTask() Get the next task to execute
boolean	isStarted() Have we been started ?
boolean	isWorkLeft() Is there something left to do?
void	setWorkExpected(boolean workExpected) In case we expect that the queue empties in between (since we are feeding in tasks slowly and the tasks finish fast), but we want to avoid isWorkLeft() to return * the "wrong message", we can use this.
void	waitStart() Block a thread until we are started

Methods inherited from class java.lang.Object

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

Field Detail

tasks

protected java.util.LinkedList tasks

The queue of Files which need to be processed

started

protected boolean started

Did we allready have an assignement?

workExpected

protected boolean workExpected

Can we finish now?

cLock

protected java.lang.Object cLock

Lock for counting

Constructor Detail

TaskQueue

public TaskQueue()

Construct a queue.

Method Detail

getTask

public java.lang.Runnable getTask()
                           throws java.lang.InterruptedException

Get the next task to execute

Specified by:

getTask in interface TaskSource

Returns:

a Task to be executed.

Throws:

java.lang.InterruptedException - when the running task gets interrupted.

addTask

public void addTask(java.lang.Runnable r)

Add a task to execute

setWorkExpected

public void setWorkExpected(boolean workExpected)

In case we expect that the queue empties in between (since we are feeding in tasks slowly and the tasks finish fast), but we want to avoid isWorkLeft() to return * the "wrong message", we can use this.

 TaskQueue tq = new TaskQueue(...)
 tq.setWorkExpected(true);
 ....
 

But one must not fail to call

 tq.setWorkExpected(false);
 

when no feeds are expected any more, since, otherwise isWorkLeft() will return true forever!

isStarted

public boolean isStarted()

Have we been started ?

Specified by:

isStarted in interface TaskSource

Returns:

true if something has been done.

isWorkLeft

public boolean isWorkLeft()

Is there something left to do? As long as we expect new work to come, this is true; If we do not expect more work to come, it depends on what we have left.

Specified by:

isWorkLeft in interface TaskSource

Returns:

true if there is still something to do.

waitStart

public void waitStart()
               throws java.lang.InterruptedException

Description copied from interface: TaskSource

Block a thread until we are started

Specified by:

waitStart in interface TaskSource

Throws:

java.lang.InterruptedException - when the running task gets interrupted.