org.apache.commons.collections4.queue

## Class SynchronizedQueue<E>

- java.lang.Object
- - org.apache.commons.collections4.collection.SynchronizedCollection<E>
  - - org.apache.commons.collections4.queue.SynchronizedQueue<E>

- Type Parameters:
    `E` - the type of the elements in the collection
  All Implemented Interfaces:
    Serializable, Iterable<E>, Collection<E>, Queue<E>

      public class SynchronizedQueue<E>
      extends SynchronizedCollection<E>
      implements Queue<E>

  Decorates another `Queue` to synchronize its behaviour for a multi-threaded environment.

  Methods are synchronized, then forwarded to the decorated queue. Iterators must be separately synchronized around the loop.

  Since:
    4.2
  See Also:
    Serialized Form

- - ### Field Summary

    - ### Fields inherited from class org.apache.commons.collections4.collection.SynchronizedCollection

      `lock`

  - ### Constructor Summary

    Constructors
    Modifier | Constructor and Description
    --- | ---
    `protected` | `SynchronizedQueue(Queue<E> queue)` Constructor that wraps (not copies).
    `protected` | `SynchronizedQueue(Queue<E> queue, Object lock)` Constructor that wraps (not copies).

  - ### Method Summary

    All Methods Static Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `protected Queue<E>` | `decorated()` Gets the queue being decorated.
    `E` | `element()`
    `boolean` | `equals(Object object)`
    `int` | `hashCode()`
    `boolean` | `offer(E e)`
    `E` | `peek()`
    `E` | `poll()`
    `E` | `remove()`
    `static <E> SynchronizedQueue<E>` | `synchronizedQueue(Queue<E> queue)` Factory method to create a synchronized queue.

    - ### Methods inherited from class org.apache.commons.collections4.collection.SynchronizedCollection

      `add, addAll, clear, contains, containsAll, isEmpty, iterator, remove, removeAll, removeIf, retainAll, size, synchronizedCollection, toArray, toArray, toString`

    - ### Methods inherited from class java.lang.Object

      `clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

    - ### Methods inherited from interface java.util.Queue

      `add`

    - ### Methods inherited from interface java.util.Collection

      `addAll, clear, contains, containsAll, isEmpty, iterator, parallelStream, remove, removeAll, removeIf, retainAll, size, spliterator, stream, toArray, toArray`

    - ### Methods inherited from interface java.lang.Iterable

      `forEach`

- - ### Constructor Detail

    - #### SynchronizedQueue

          protected SynchronizedQueue(Queue<E> queue)

      Constructor that wraps (not copies).
      Parameters:
        `queue` - the queue to decorate, must not be null
      Throws:
        `NullPointerException` - if queue is null

    - #### SynchronizedQueue

          protected SynchronizedQueue(Queue<E> queue,
                                      Object lock)

      Constructor that wraps (not copies).
      Parameters:
        `queue` - the queue to decorate, must not be null
        `lock` - the lock to use, must not be null
      Throws:
        `NullPointerException` - if queue or lock is null

  - ### Method Detail

    - #### synchronizedQueue

          public static <E> SynchronizedQueue<E> synchronizedQueue(Queue<E> queue)

      Factory method to create a synchronized queue.
      Type Parameters:
        `E` - the type of the elements in the queue
      Parameters:
        `queue` - the queue to decorate, must not be null
      Returns:
        a new synchronized Queue
      Throws:
        `NullPointerException` - if queue is null

    - #### decorated

          protected Queue<E> decorated()

      Gets the queue being decorated.
      Overrides:
        `decorated` in class `SynchronizedCollection<E>`
      Returns:
        the decorated queue

    - #### element

          public E element()

      Specified by:
        `element` in interface `Queue<E>`

    - #### equals

          public boolean equals(Object object)

      Specified by:
        `equals` in interface `Collection<E>`
      Overrides:
        `equals` in class `SynchronizedCollection<E>`

    - #### hashCode

          public int hashCode()

      Specified by:
        `hashCode` in interface `Collection<E>`
      Overrides:
        `hashCode` in class `SynchronizedCollection<E>`

    - #### offer

          public boolean offer(E e)

      Specified by:
        `offer` in interface `Queue<E>`

    - #### peek

          public E peek()

      Specified by:
        `peek` in interface `Queue<E>`

    - #### poll

          public E poll()

      Specified by:
        `poll` in interface `Queue<E>`

    - #### remove

          public E remove()

      Specified by:
        `remove` in interface `Queue<E>`

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