UnmodifiableQueue

org.apache.commons.collections4.queue

Class UnmodifiableQueue<E>

java.lang.Object
- org.apache.commons.collections4.collection.AbstractCollectionDecorator<E>
- - org.apache.commons.collections4.queue.AbstractQueueDecorator<E>
  - - org.apache.commons.collections4.queue.UnmodifiableQueue<E>

All Implemented Interfaces:

Serializable, Iterable<E>, Collection<E>, Queue<E>, Unmodifiable
```
public final class UnmodifiableQueue<E>
extends AbstractQueueDecorator<E>
implements Unmodifiable
```
Decorates another Queue to ensure it can't be altered.
Attempts to modify it will result in an UnsupportedOperationException.

Since:

4.0

See Also:

Serialized Form

Method Summary

All Methods

Static Methods

Instance Methods

Concrete Methods
Modifier and Type	Method and Description
`boolean`	`add(Object object)`
`boolean`	`addAll(Collection<? extends E> coll)`
`void`	`clear()`
`Iterator<E>`	`iterator()`
`boolean`	`offer(E obj)`
`E`	`poll()`
`E`	`remove()`
`boolean`	`remove(Object object)`
`boolean`	`removeAll(Collection<?> coll)`
`boolean`	`retainAll(Collection<?> coll)`
`static <E> Queue<E>`	`unmodifiableQueue(Queue<? extends E> queue)` Factory method to create an unmodifiable queue.

Methods inherited from class org.apache.commons.collections4.queue.AbstractQueueDecorator
decorated, element, peek

Methods inherited from class org.apache.commons.collections4.collection.AbstractCollectionDecorator
contains, containsAll, isEmpty, setCollection, size, toArray, toArray, toString

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Collection
contains, containsAll, equals, hashCode, isEmpty, parallelStream, removeIf, size, spliterator, stream, toArray, toArray

Methods inherited from interface java.lang.Iterable
forEach

Method Detail

unmodifiableQueue
```
public static <E> Queue<E> unmodifiableQueue(Queue<? extends E> queue)
```
Factory method to create an unmodifiable queue.
If the queue passed in is already unmodifiable, it is returned.

Type Parameters:

E - the type of the elements in the queue

Parameters:

queue - the queue to decorate, must not be null

Returns:

an unmodifiable Queue

Throws:

NullPointerException - if queue is null

iterator
```
public Iterator<E> iterator()
```

add
```
public boolean add(Object object)
```

addAll

public boolean addAll(Collection<? extends E> coll)

clear
```
public void clear()
```

remove
```
public boolean remove(Object object)
```

removeAll

public boolean removeAll(Collection<?> coll)

retainAll

public boolean retainAll(Collection<?> coll)

offer
```
public boolean offer(E obj)
```

poll
```
public E poll()
```

remove
```
public E remove()
```