Class TaskQueue

java.lang.Object

java.util.AbstractCollection<Runnable>

java.util.AbstractQueue<Runnable>

java.util.concurrent.LinkedBlockingQueue<Runnable>

org.apache.tomcat.util.threads.TaskQueue

All Implemented Interfaces:

Serializable, Iterable<Runnable>, Collection<Runnable>, BlockingQueue<Runnable>, Queue<Runnable>, RetryableQueue<Runnable>

public class TaskQueue
extends LinkedBlockingQueue<Runnable>
implements RetryableQueue<Runnable>

As task queue specifically designed to run with a thread pool executor. The task queue is optimised to properly utilize threads within a thread pool executor. If you use a normal queue, the executor will spawn threads when there are idle threads and you won't be able to force items onto the queue itself.

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
protected static final StringManager	sm	The string manager for this package.

Constructor Summary

Constructors

Constructor	Description
TaskQueue()	Constructs a new TaskQueue with default capacity.
TaskQueue(int capacity)	Constructs a new TaskQueue with the given capacity.
TaskQueue(Collection<? extends Runnable> c)	Constructs a new TaskQueue containing the elements in the given collection.

Method Summary

Modifier and Type	Method	Description
boolean	force(Runnable o)	Used to add a task to the queue if the task has been rejected by the Executor.
boolean	offer(Runnable o)
Runnable	poll(long timeout, TimeUnit unit)
void	setParent(ThreadPoolExecutor tp)	Sets the parent thread pool executor for this queue.
Runnable	take()

Methods inherited from class LinkedBlockingQueue

clear, contains, drainTo, drainTo, forEach, iterator, offer, peek, poll, put, remainingCapacity, remove, removeAll, removeIf, retainAll, size, spliterator, toArray, toArray, toString

Methods inherited from class AbstractQueue

add, addAll, element, remove

Methods inherited from class AbstractCollection

containsAll, isEmpty

Methods inherited from class Object

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

Methods inherited from interface BlockingQueue

add, contains, drainTo, drainTo, offer, put, remainingCapacity, remove

Methods inherited from interface Collection

addAll, clear, containsAll, equals, hashCode, isEmpty, iterator, parallelStream, removeAll, removeIf, retainAll, size, spliterator, stream, toArray, toArray, toArray

Methods inherited from interface Iterable

forEach

Methods inherited from interface Queue

element, peek, poll, remove

Field Details

sm

protected static final StringManager sm

The string manager for this package.

Constructor Details

TaskQueue

public TaskQueue()

Constructs a new TaskQueue with default capacity.

TaskQueue

public TaskQueue(int capacity)

Constructs a new TaskQueue with the given capacity.

Parameters:

capacity - the queue capacity

TaskQueue

public TaskQueue(Collection<? extends Runnable> c)

Constructs a new TaskQueue containing the elements in the given collection.

Parameters:

c - the collection of initial elements

Method Details

setParent

public void setParent(ThreadPoolExecutor tp)

Sets the parent thread pool executor for this queue.

Parameters:

tp - the parent executor

force

public boolean force(Runnable o)

Description copied from interface: RetryableQueue

Used to add a task to the queue if the task has been rejected by the Executor.

Specified by:

force in interface RetryableQueue<Runnable>

Parameters:

o - The task to add to the queue

Returns:

true if the task was added to the queue, otherwise false

offer

public boolean offer(Runnable o)

Specified by:

offer in interface BlockingQueue<Runnable>

Specified by:

offer in interface Queue<Runnable>

Overrides:

offer in class LinkedBlockingQueue<Runnable>

poll

public Runnable poll(long timeout,
 TimeUnit unit)
              throws InterruptedException

Specified by:

poll in interface BlockingQueue<Runnable>

Overrides:

poll in class LinkedBlockingQueue<Runnable>

Throws:

InterruptedException

take

public Runnable take()
              throws InterruptedException

Specified by:

take in interface BlockingQueue<Runnable>

Overrides:

take in class LinkedBlockingQueue<Runnable>

Throws:

InterruptedException