org.multiverse.utils
Class StandardThreadFactory

java.lang.Object
  org.multiverse.utils.StandardThreadFactory

All Implemented Interfaces:

ThreadFactory

public final class StandardThreadFactory
extends Object
implements ThreadFactory

A customizable implementation of the ThreadFactory. The new java.util.concurrency library provides a ThreadFactory interface, which is a great thing, but strangely enough it doesn't provide an customizable implementation.

If the maximum priority of the threadgroup is changed after this StandardThreadFactory is constructed, then this will be ignored by the StandardThreadFactory. So it could be that a StandardThreadFactory has a higher priority than the threadgroup allowed. What will happen at construction?

Author:

Peter Veentjer.

Constructor Summary

StandardThreadFactory()
Constructs a new StandardThreadFactory with a Thread.NORM_PRIORITY as priority and a newly created ThreadGroup.

StandardThreadFactory(int priority)
Constructs a new StandardThreadFactory with the given priority.

StandardThreadFactory(int priority, boolean daemon)

StandardThreadFactory(int priority, String groupName)
Constructs a new StandardThreadFactory with the given priority and with a newly created ThreadGroup with the given groupname.

StandardThreadFactory(int priority, ThreadGroup threadGroup)
Constructs a new StandardThreadFactory with the given priority and are part of the give ThreadGroup.

StandardThreadFactory(int priority, ThreadGroup threadGroup, boolean daemon)
Constructs a new StandardThreadFactory with the given priority and threadgroup.

StandardThreadFactory(String groupName)
Constructs a new StandardThreadFactory with a Thread.NORM_PRIORITY as priority and with a newly created ThreadGroup with the given groupName.

Method Summary

int	getPriority() Returns the priority of created Threads.
ThreadGroup	getThreadGroup() Returns the ThreadGroup of the created Threads.
boolean	isProducingDaemons() Returns true if this StandardThreadFactory is producing deamon threads, false otherwise.
Thread	newThread(Runnable runnable)
void	setPriority(int priority) Sets the priority of the threads.

Methods inherited from class java.lang.Object

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

Constructor Detail

StandardThreadFactory

public StandardThreadFactory()

Constructs a new StandardThreadFactory with a Thread.NORM_PRIORITY as priority and a newly created ThreadGroup. The created Threads are not daemons.

StandardThreadFactory

public StandardThreadFactory(String groupName)

Constructs a new StandardThreadFactory with a Thread.NORM_PRIORITY as priority and with a newly created ThreadGroup with the given groupName. The created threads are not daemons.

Parameters:

groupName - the name of the ThreadGroup (is allowed to be null).

StandardThreadFactory

public StandardThreadFactory(int priority)

Constructs a new StandardThreadFactory with the given priority. The created threads are not daemons.

Parameters:

priority - the priority of th threads.

Throws:

IllegalArgumentException - if the priority is not valid.

StandardThreadFactory

public StandardThreadFactory(int priority,
                             String groupName)

Constructs a new StandardThreadFactory with the given priority and with a newly created ThreadGroup with the given groupname. The created threads are not daemons.

Parameters:

priority - the priority of the threads this StandardThreadFactory is going to createReference.

groupName - the name of the ThreadGroup (is allowed to be null).

Throws:

IllegalArgumentException - if priority is not a valid value.

StandardThreadFactory

public StandardThreadFactory(int priority,
                             ThreadGroup threadGroup)

Constructs a new StandardThreadFactory with the given priority and are part of the give ThreadGroup. The created threads are not deamons.

Parameters:

priority - the priority of the created threads.

threadGroup - the ThreadGroup the created Threads are part of.

Throws:

NullPointerException - if threadGroup is null

IllegalArgumentException - if the priority is not valid value.

StandardThreadFactory

public StandardThreadFactory(int priority,
                             boolean daemon)

StandardThreadFactory

public StandardThreadFactory(int priority,
                             ThreadGroup threadGroup,
                             boolean daemon)

Constructs a new StandardThreadFactory with the given priority and threadgroup.

Parameters:

priority - the priority of the threads this StandardThreadFactory is going to createReference.

threadGroup - the threadgroup the thread is part of

daemon - if the thread should be a daemon.

Throws:

IllegalArgumentException - if the priority is not valid.

NullPointerException - if threadGroup is null.

Method Detail

isProducingDaemons

public boolean isProducingDaemons()

Returns true if this StandardThreadFactory is producing deamon threads, false otherwise.

Returns:

true if this StandardThreadFactory is producing deamon threads, false otherwise.

getThreadGroup

public ThreadGroup getThreadGroup()

Returns the ThreadGroup of the created Threads.

Returns:

the ThreadGroup of the created Threads.

getPriority

public int getPriority()

Returns the priority of created Threads. This is a value ranging from Thread.MIN_PRIORITY to Thread.MAX_PRIORITY.

Returns:

the priortity of created Threads.

setPriority

public void setPriority(int priority)

Sets the priority of the threads. This will only effect newly created Threads. A value must be set ranging from Thread.MIN_PRIORITY and Thread.MAX_PRIORITY.

This call is not completely threadsafe, the following scenario could happen:

1. thread1 call setPriority and start the checking part of this method and the check passes
2. thread2 calls the threadgroup directly and lowers the priority
3. thread1 sets the priority on this StandardThreadFactory

The consequence is that the priority of this StandardThreadFactory is higher than the maximum priority of the ThreadGroup and this means that thread creation could fail because threads are created with a too high priority. This race problem is very hard to prevent because the check/set can't be done atomic because the ThreadGroup is exposed.

Parameters:

priority - the new priority.

Throws:

IllegalArgumentException - if priority is smaller than Thread.MIN_PRIORITY or larger than Thread.MAX_PRIORITY or larger than the maximum priority of the ThreadGroup.

newThread

public Thread newThread(Runnable runnable)

Specified by:

newThread in interface ThreadFactory