Package org.eclipse.jetty.util.thread

Class ReservedThreadExecutor

java.lang.Object

org.eclipse.jetty.util.component.AbstractLifeCycle

org.eclipse.jetty.util.thread.ReservedThreadExecutor

All Implemented Interfaces:

Executor, Dumpable, LifeCycle, TryExecutor

@ManagedObject("A pool for reserved threads")
public class ReservedThreadExecutor
extends AbstractLifeCycle
implements TryExecutor, Dumpable

A TryExecutor using pre-allocated/reserved threads from an external Executor.

Calls to tryExecute(Runnable) on ReservedThreadExecutor will either succeed with a reserved thread immediately being assigned the task, or fail if no reserved thread is available.

Threads are reserved lazily, with new reserved threads being allocated from the external Executor passed to the constructor. Whenever 1 or more reserved threads have been idle for more than getIdleTimeoutMs() then one reserved thread will return to the external Executor.

Nested Class Summary

Nested classes/interfaces inherited from class org.eclipse.jetty.util.component.AbstractLifeCycle

AbstractLifeCycle.AbstractLifeCycleListener, AbstractLifeCycle.StopException

Nested classes/interfaces inherited from interface org.eclipse.jetty.util.component.Dumpable

Dumpable.DumpableContainer

Nested classes/interfaces inherited from interface org.eclipse.jetty.util.component.LifeCycle

LifeCycle.Listener

Nested classes/interfaces inherited from interface org.eclipse.jetty.util.thread.TryExecutor

TryExecutor.NoTryExecutor

Field Summary

Fields inherited from class org.eclipse.jetty.util.component.AbstractLifeCycle

FAILED, STARTED, STARTING, STOPPED, STOPPING

Fields inherited from interface org.eclipse.jetty.util.component.Dumpable

KEY

Fields inherited from interface org.eclipse.jetty.util.thread.TryExecutor

NO_TRY

Constructor Summary

Constructors

Constructor	Description
ReservedThreadExecutor(Executor executor, int capacity)

Method Summary

Modifier and Type	Method	Description
void	doStart()	Method to override to start the lifecycle
void	doStop()	Method to override to stop the lifecycle
void	dump(Appendable out, String indent)	Dump this object (and children) into an Appendable using the provided indent after any new lines.
void	execute(Runnable task)
int	getAvailable()
int	getCapacity()
Executor	getExecutor()
long	getIdleTimeoutMs()
int	getPending()
void	setIdleTimeout(long idleTime, TimeUnit idleTimeUnit)	Set the idle timeout for shrinking the reserved thread pool
String	toString()
boolean	tryExecute(Runnable task)	Executes the given task if and only if a reserved thread is available.

Methods inherited from class org.eclipse.jetty.util.component.AbstractLifeCycle

addEventListener, getEventListeners, getState, getState, isFailed, isRunning, isStarted, isStarting, isStopped, isStopping, removeEventListener, setEventListeners, start, stop

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.eclipse.jetty.util.component.Dumpable

dump, dumpSelf

Constructor Details

ReservedThreadExecutor

public ReservedThreadExecutor(Executor executor,
 int capacity)

Parameters:

executor - The executor to use to obtain threads

capacity - The number of threads to preallocate. If less than 0 then capacity is calculated based on a heuristic from the number of available processors and thread pool size.

Method Details

getExecutor

public Executor getExecutor()

getCapacity

@ManagedAttribute(value="max number of reserved threads",
                  readonly=true)
public int getCapacity()

Returns:

the maximum number of reserved threads

getAvailable

@ManagedAttribute(value="available reserved threads",
                  readonly=true)
public int getAvailable()

Returns:

the number of threads available to tryExecute(Runnable)

getPending

@ManagedAttribute(value="pending reserved threads",
                  readonly=true)
public int getPending()

getIdleTimeoutMs

@ManagedAttribute(value="idle timeout in ms",
                  readonly=true)
public long getIdleTimeoutMs()

setIdleTimeout

public void setIdleTimeout(long idleTime,
 TimeUnit idleTimeUnit)

Set the idle timeout for shrinking the reserved thread pool

Parameters:

idleTime - Time to wait before shrinking, or 0 for default timeout.

idleTimeUnit - Time units for idle timeout

doStart

public void doStart()
             throws Exception

Description copied from class: AbstractLifeCycle

Method to override to start the lifecycle

Overrides:

doStart in class AbstractLifeCycle

Throws:

Exception - If there was a problem starting. Will cause a transition to FAILED state

doStop

public void doStop()
            throws Exception

Description copied from class: AbstractLifeCycle

Method to override to stop the lifecycle

Overrides:

doStop in class AbstractLifeCycle

Throws:

Exception - If there was a problem stopping. Will cause a transition to FAILED state

execute

public void execute(Runnable task)
             throws RejectedExecutionException

Specified by:

execute in interface Executor

Specified by:

execute in interface TryExecutor

Throws:

RejectedExecutionException

tryExecute

public boolean tryExecute(Runnable task)

Executes the given task if and only if a reserved thread is available.

Specified by:

tryExecute in interface TryExecutor

Parameters:

task - the task to run

Returns:

true if and only if a reserved thread was available and has been assigned the task to run.

dump

public void dump(Appendable out,
 String indent)
          throws IOException

Description copied from interface: Dumpable

Dump this object (and children) into an Appendable using the provided indent after any new lines. The indent should not be applied to the first object dumped.

Specified by:

dump in interface Dumpable

Parameters:

out - The appendable to dump to

indent - The indent to apply after any new lines.

Throws:

IOException - if unable to write to Appendable

toString

public String toString()

Overrides:

toString in class AbstractLifeCycle