Package org.apache.tomcat.util.threads

Class TaskQueue

  • All Implemented Interfaces:
    java.io.Serializable, java.lang.Iterable<java.lang.Runnable>, java.util.Collection<java.lang.Runnable>, java.util.concurrent.BlockingQueue<java.lang.Runnable>, java.util.Queue<java.lang.Runnable>, RetryableQueue<java.lang.Runnable>
    public class TaskQueue
extends java.util.concurrent.LinkedBlockingQueue<java.lang.Runnable>
implements RetryableQueue<java.lang.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 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​(java.util.Collection<? extends java.lang.Runnable> c)
      Constructs a new TaskQueue containing the elements in the given collection.

    • Method Summary

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

      • Methods inherited from class java.util.concurrent.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 java.util.AbstractQueue

        add, addAll, element, remove

      • Methods inherited from class java.util.AbstractCollection

        containsAll, isEmpty

      • Methods inherited from class java.lang.Object

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

      • Methods inherited from interface java.util.concurrent.BlockingQueue

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

      • Methods inherited from interface java.util.Collection

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

      • Methods inherited from interface java.lang.Iterable

        forEach

      • Methods inherited from interface java.util.Queue

        element, peek, poll, remove

    • Field Detail

      • sm

        protected static final StringManager sm
        The string manager for this package.

    • Constructor Detail

      • 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​(java.util.Collection<? extends java.lang.Runnable> c)
        Constructs a new TaskQueue containing the elements in the given collection.
        Parameters:
        c - the collection of initial elements

    • Method Detail

      • setParent

        public void setParent​(ThreadPoolExecutor tp)
        Sets the parent thread pool executor for this queue.
        Parameters:
        tp - the parent executor

      • force

        public boolean force​(java.lang.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<java.lang.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​(java.lang.Runnable o)
        Specified by:
        offer in interface java.util.concurrent.BlockingQueue<java.lang.Runnable>
        Specified by:
        offer in interface java.util.Queue<java.lang.Runnable>
        Overrides:
        offer in class java.util.concurrent.LinkedBlockingQueue<java.lang.Runnable>

      • poll

        public java.lang.Runnable poll​(long timeout,
                               java.util.concurrent.TimeUnit unit)
                        throws java.lang.InterruptedException
        Specified by:
        poll in interface java.util.concurrent.BlockingQueue<java.lang.Runnable>
        Overrides:
        poll in class java.util.concurrent.LinkedBlockingQueue<java.lang.Runnable>
        Throws:
        java.lang.InterruptedException

      • take

        public java.lang.Runnable take()
                        throws java.lang.InterruptedException
        Specified by:
        take in interface java.util.concurrent.BlockingQueue<java.lang.Runnable>
        Overrides:
        take in class java.util.concurrent.LinkedBlockingQueue<java.lang.Runnable>
        Throws:
        java.lang.InterruptedException