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:

java.util.concurrent.Executor, LifeCycle

@ManagedObject("A pool for reserved threads")
public class ReservedThreadExecutor
extends AbstractLifeCycle
implements java.util.concurrent.Executor

An Executor using preallocated/reserved Threads from a wrapped Executor.

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

Threads are reserved lazily, with a new reserved thread being allocated from a wrapped Executor when an execution fails. If the setIdleTimeout(long, TimeUnit) is set to non zero (default 1 minute), then the reserved thread pool will shrink by 1 thread whenever it has been idle for that period.

Nested Class Summary

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

AbstractLifeCycle.AbstractLifeCycleListener

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

LifeCycle.Listener

Field Summary

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

FAILED, RUNNING, STARTED, STARTING, STOP_ON_FAILURE, STOPPED, STOPPING

Constructor Summary

Constructors

Constructor	Description
ReservedThreadExecutor(java.util.concurrent.Executor executor)
ReservedThreadExecutor(java.util.concurrent.Executor executor, int capacity)
ReservedThreadExecutor(java.util.concurrent.Executor executor, int capacity, java.lang.Object owner)

Method Summary

Modifier and Type	Method	Description
void	doStart()
void	doStop()
void	execute(java.lang.Runnable task)
int	getAvailable()
int	getCapacity()
java.util.concurrent.Executor	getExecutor()
long	getIdleTimeoutMs()
int	getPending()
static int	reservedThreads(java.util.concurrent.Executor executor, int capacity)
void	setIdleTimeout(long idleTime, java.util.concurrent.TimeUnit idleTimeUnit)	Set the idle timeout for shrinking the reserved thread pool
java.lang.String	toString()
boolean	tryExecute(java.lang.Runnable task)

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

addLifeCycleListener, getState, getState, getStopTimeout, isFailed, isRunning, isStarted, isStarting, isStopped, isStopping, removeLifeCycleListener, setStopTimeout, start, stop

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

start, stop

Methods inherited from class java.lang.Object

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

Constructor Detail

ReservedThreadExecutor

public ReservedThreadExecutor(java.util.concurrent.Executor executor)

ReservedThreadExecutor

public ReservedThreadExecutor(java.util.concurrent.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.

ReservedThreadExecutor

public ReservedThreadExecutor(java.util.concurrent.Executor executor,
                              int capacity,
                              java.lang.Object owner)

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 Detail

reservedThreads

public static int reservedThreads(java.util.concurrent.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.

Returns:

the number of reserved threads that would be used by a ReservedThreadExecutor constructed with these arguments.

getExecutor

public java.util.concurrent.Executor getExecutor()

getCapacity

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

getAvailable

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

getPending

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

getIdleTimeoutMs

@ManagedAttribute(value="idletimeout in MS",
                  readonly=true)
public long getIdleTimeoutMs()

setIdleTimeout

public void setIdleTimeout(long idleTime,
                           java.util.concurrent.TimeUnit idleTimeUnit)

Set the idle timeout for shrinking the reserved thread pool

Parameters:

idleTime - Time to wait before shrinking, or 0 for no timeout.

idleTimeUnit - Time units for idle timeout

doStart

public void doStart()
             throws java.lang.Exception

Overrides:

doStart in class AbstractLifeCycle

Throws:

java.lang.Exception

doStop

public void doStop()
            throws java.lang.Exception

Overrides:

doStop in class AbstractLifeCycle

Throws:

java.lang.Exception

execute

public void execute(java.lang.Runnable task)
             throws java.util.concurrent.RejectedExecutionException

Specified by:

execute in interface java.util.concurrent.Executor

Throws:

java.util.concurrent.RejectedExecutionException

tryExecute

public boolean tryExecute(java.lang.Runnable task)

Parameters:

task - The task to run

Returns:

True iff a reserved thread was available and has been assigned the task to run.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object