Apache Commons Collections 4.4 · org.apache.commons.collections4.queue.SynchronizedQueue

Modifier and Type	Field and Description
private static final long	serialVersionUID Hides org.apache.commons.collections4.collection.SynchronizedCollection.serialVersionUID. Serialization version

Access	Constructor and Description
protected	SynchronizedQueue(final Queue<E> the queue to decorate, must not be null queue) Constructor that wraps (not copies).
protected	SynchronizedQueue(final Queue<E> the queue to decorate, must not be null queue, final Object the lock to use, must not be null lock) Constructor that wraps (not copies).

Method Summary

Modifier and Type	Method and Description
protected Queue<E>	Returns: the decorated queue decorated() Overrides org.apache.commons.collections4.collection.SynchronizedCollection.decorated. Gets the queue being decorated.
public E	element() Implements java.util.Queue.element. Retrieves, but does not remove, the head of this queue.
public boolean	equals(final Object object to be compared for equality with this collection object) Overrides org.apache.commons.collections4.collection.SynchronizedCollection.equals. Implements java.util.Collection.equals. Compares the specified object with this collection for equality.
public int	hashCode() Overrides org.apache.commons.collections4.collection.SynchronizedCollection.hashCode. Implements java.util.Collection.hashCode. Returns the hash code value for this collection.
public boolean	offer(final E the element to add e) Implements java.util.Queue.offer. Inserts the specified element into this queue if it is possible to do so immediately without violating capacity restrictions.
public E	peek() Implements java.util.Queue.peek. Retrieves, but does not remove, the head of this queue, or returns `null` if this queue is empty.
public E	poll() Implements java.util.Queue.poll. Retrieves and removes the head of this queue, or returns `null` if this queue is empty.
public E	remove() Implements java.util.Queue.remove. Retrieves and removes the head of this queue.
public static < the type of the elements in the queue E> SynchronizedQueue<E>	Returns: a new synchronized Queue synchronizedQueue(final Queue<E> the queue to decorate, must not be null queue) Factory method to create a synchronized queue.

Inherited from org.apache.commons.collections4.collection.SynchronizedCollection:: add addAll clear contains containsAll isEmpty iterator remove removeAll removeIf retainAll size synchronizedCollection toArray toArray toString

serialVersionUID	back to summary
private static final long serialVersionUID Hides org.apache.commons.collections4.collection.SynchronizedCollection.serialVersionUID. Serialization version

SynchronizedQueue	back to summary
protected SynchronizedQueue(final Queue<E> queue) Constructor that wraps (not copies). Parameters queue:Queue<E> the queue to decorate, must not be null Exceptions NullPointerException: if queue is null

SynchronizedQueue	back to summary
protected SynchronizedQueue(final Queue<E> queue, final Object lock) Constructor that wraps (not copies). Parameters queue:Queue<E> the queue to decorate, must not be null lock:Object the lock to use, must not be null Exceptions NullPointerException: if queue or lock is null

Method Detail

decorated	back to summary
protected Queue<E> decorated() Overrides org.apache.commons.collections4.collection.SynchronizedCollection.decorated. Gets the queue being decorated. Returns:Queue<E> the decorated queue Annotations @Override

decorated

back to summary

protected Queue<E> decorated()

Overrides org.apache.commons.collections4.collection.SynchronizedCollection.decorated.

Gets the queue being decorated.

Returns:Queue<E>

the decorated queue

Annotations

@Override

element back to summary

element	back to summary
public E element() Implements java.util.Queue.element. Doc from java.util.Queue.element. Retrieves, but does not remove, the head of this queue. This method differs from `peek` only in that it throws an exception if this queue is empty. Returns:E the head of this queue Annotations @Override

public E element()

Implements java.util.Queue.element.

Doc from java.util.Queue.element.

Retrieves, but does not remove, the head of this queue. This method differs from peek only in that it throws an exception if this queue is empty.

Returns:E

the head of this queue

Annotations

@Override

equals back to summary

equals	back to summary
public boolean equals(final Object object) Overrides org.apache.commons.collections4.collection.SynchronizedCollection.equals. Implements java.util.Collection.equals. Doc from java.util.Collection.equals. Compares the specified object with this collection for equality. While the `Collection` interface adds no stipulations to the general contract for the `Object.equals`, programmers who implement the `Collection` interface "directly" (in other words, create a class that is a `Collection` but is not a `Set` or a `List`) must exercise care if they choose to override the `Object.equals`. It is not necessary to do so, and the simplest course of action is to rely on `Object`'s implementation, but the implementor may wish to implement a "value comparison" in place of the default "reference comparison." (The `List` and `Set` interfaces mandate such value comparisons.) The general contract for the `Object.equals` method states that equals must be symmetric (in other words, `a.equals(b)` if and only if `b.equals(a)`). The contracts for `List.equals` and `Set.equals` state that lists are only equal to other lists, and sets to other sets. Thus, a custom `equals` method for a collection class that implements neither the `List` nor `Set` interface must return `false` when this collection is compared to any list or set. (By the same logic, it is not possible to write a class that correctly implements both the `Set` and `List` interfaces.) Parameters object:Object object to be compared for equality with this collection Returns:boolean `true` if the specified object is equal to this collection Annotations @Override

public boolean equals(final Object object)

Overrides org.apache.commons.collections4.collection.SynchronizedCollection.equals.

Implements java.util.Collection.equals.

Doc from java.util.Collection.equals.

Compares the specified object with this collection for equality.

While the Collection interface adds no stipulations to the general contract for the Object.equals, programmers who implement the Collection interface "directly" (in other words, create a class that is a Collection but is not a Set or a List) must exercise care if they choose to override the Object.equals. It is not necessary to do so, and the simplest course of action is to rely on Object's implementation, but the implementor may wish to implement a "value comparison" in place of the default "reference comparison." (The List and Set interfaces mandate such value comparisons.)

The general contract for the Object.equals method states that equals must be symmetric (in other words, a.equals(b) if and only if b.equals(a)). The contracts for List.equals and Set.equals state that lists are only equal to other lists, and sets to other sets. Thus, a custom equals method for a collection class that implements neither the List nor Set interface must return false when this collection is compared to any list or set. (By the same logic, it is not possible to write a class that correctly implements both the Set and List interfaces.)

Parameters

object:Object: object to be compared for equality with this collection

Returns:boolean

true if the specified object is equal to this collection

Annotations

@Override

hashCode back to summary

hashCode	back to summary
public int hashCode() Overrides org.apache.commons.collections4.collection.SynchronizedCollection.hashCode. Implements java.util.Collection.hashCode. Doc from java.util.Collection.hashCode. Returns the hash code value for this collection. While the `Collection` interface adds no stipulations to the general contract for the `Object.hashCode` method, programmers should take note that any class that overrides the `Object.equals` method must also override the `Object.hashCode` method in order to satisfy the general contract for the `Object.hashCode` method. In particular, `c1.equals(c2)` implies that `c1.hashCode()==c2.hashCode()`. Returns:int the hash code value for this collection Annotations @Override

public int hashCode()

Overrides org.apache.commons.collections4.collection.SynchronizedCollection.hashCode.

Implements java.util.Collection.hashCode.

Doc from java.util.Collection.hashCode.

Returns the hash code value for this collection. While the Collection interface adds no stipulations to the general contract for the Object.hashCode method, programmers should take note that any class that overrides the Object.equals method must also override the Object.hashCode method in order to satisfy the general contract for the Object.hashCode method. In particular, c1.equals(c2) implies that c1.hashCode()==c2.hashCode().

Returns:int

the hash code value for this collection

Annotations

@Override

offer back to summary

offer	back to summary
public boolean offer(final E e) Implements java.util.Queue.offer. Doc from java.util.Queue.offer. Inserts the specified element into this queue if it is possible to do so immediately without violating capacity restrictions. When using a capacity-restricted queue, this method is generally preferable to `add`, which can fail to insert an element only by throwing an exception. Parameters e:E the element to add Returns:boolean `true` if the element was added to this queue, else `false` Annotations @Override

public boolean offer(final E e)

Implements java.util.Queue.offer.

Doc from java.util.Queue.offer.

Inserts the specified element into this queue if it is possible to do so immediately without violating capacity restrictions. When using a capacity-restricted queue, this method is generally preferable to add, which can fail to insert an element only by throwing an exception.

Parameters

e:E: the element to add

Returns:boolean

true if the element was added to this queue, else false

Annotations

@Override

peek back to summary

peek	back to summary
public E peek() Implements java.util.Queue.peek. Doc from java.util.Queue.peek. Retrieves, but does not remove, the head of this queue, or returns `null` if this queue is empty. Returns:E the head of this queue, or `null` if this queue is empty Annotations @Override

public E peek()

Implements java.util.Queue.peek.

Doc from java.util.Queue.peek.

Retrieves, but does not remove, the head of this queue, or returns null if this queue is empty.

Returns:E

the head of this queue, or null if this queue is empty

Annotations

@Override

poll back to summary

poll	back to summary
public E poll() Implements java.util.Queue.poll. Doc from java.util.Queue.poll. Retrieves and removes the head of this queue, or returns `null` if this queue is empty. Returns:E the head of this queue, or `null` if this queue is empty Annotations @Override

public E poll()

Implements java.util.Queue.poll.

Doc from java.util.Queue.poll.

Retrieves and removes the head of this queue, or returns null if this queue is empty.

Returns:E

the head of this queue, or null if this queue is empty

Annotations

@Override

remove back to summary

remove	back to summary
public E remove() Implements java.util.Queue.remove. Doc from java.util.Queue.remove. Retrieves and removes the head of this queue. This method differs from `poll()` only in that it throws an exception if this queue is empty. Returns:E the head of this queue Annotations @Override

public E remove()

Implements java.util.Queue.remove.

Doc from java.util.Queue.remove.

Retrieves and removes the head of this queue. This method differs from poll() only in that it throws an exception if this queue is empty.

Returns:E

the head of this queue

Annotations

@Override

synchronizedQueue	back to summary
public static <E> SynchronizedQueue<E> synchronizedQueue(final Queue<E> queue) Factory method to create a synchronized queue. Parameters <E> the type of the elements in the queue queue:Queue<E> the queue to decorate, must not be null Returns:SynchronizedQueue<E> a new synchronized Queue Exceptions NullPointerException: if queue is null

synchronizedQueue

back to summary

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

Factory method to create a synchronized queue.

Parameters

<E>: the type of the elements in the queue
queue:Queue<E>: the queue to decorate, must not be null

Returns:SynchronizedQueue<E>

a new synchronized Queue

Exceptions

NullPointerException:: if queue is null

public Class SynchronizedQueue<E>

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