ForwardingDeque (Guava: Google Core Libraries for Java 23.5-jre API)

java.lang.Object
- com.google.common.collect.ForwardingObject
- - com.google.common.collect.ForwardingCollection<E>
  - - com.google.common.collect.ForwardingQueue<E>
    - - com.google.common.collect.ForwardingDeque<E>

All Implemented Interfaces:

Iterable<E>, Collection<E>, Deque<E>, Queue<E>

Direct Known Subclasses:

ForwardingBlockingDeque, ForwardingBlockingDeque
```
@GwtIncompatible
public abstract class ForwardingDeque<E>
extends ForwardingQueue<E>
implements Deque<E>
```
A deque which forwards all its method calls to another deque. Subclasses should override one or more methods to modify the behavior of the backing deque as desired per the decorator pattern.
Warning: The methods of ForwardingDeque forward indiscriminately to the methods of the delegate. For example, overriding ForwardingCollection.add(E) alone will not change the behavior of ForwardingQueue.offer(E) which can lead to unexpected behavior. In this case, you should override offer as well.
default method warning: This class does not forward calls to default methods. Instead, it inherits their default implementations. When those implementations invoke methods, they invoke methods on the ForwardingDeque.

Since:

12.0

Author:

Kurt Alfred Kluever

Constructor Summary

Constructors
Modifier Constructor and Description

protected ForwardingDeque()
Constructor for use by subclasses.

Constructors
Modifier	Constructor and Description
`protected`	`ForwardingDeque()` Constructor for use by subclasses.

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`addFirst(E e)` Inserts the specified element at the front of this deque if it is possible to do so immediately without violating capacity restrictions, throwing an `IllegalStateException` if no space is currently available.
`void`	`addLast(E e)` Inserts the specified element at the end of this deque if it is possible to do so immediately without violating capacity restrictions, throwing an `IllegalStateException` if no space is currently available.
`protected abstract Deque<E>`	`delegate()` Returns the backing delegate instance that methods are forwarded to.
`Iterator<E>`	`descendingIterator()` Returns an iterator over the elements in this deque in reverse sequential order.
`E`	`getFirst()` Retrieves, but does not remove, the first element of this deque.
`E`	`getLast()` Retrieves, but does not remove, the last element of this deque.
`boolean`	`offerFirst(E e)` Inserts the specified element at the front of this deque unless it would violate capacity restrictions.
`boolean`	`offerLast(E e)` Inserts the specified element at the end of this deque unless it would violate capacity restrictions.
`E`	`peekFirst()` Retrieves, but does not remove, the first element of this deque, or returns `null` if this deque is empty.
`E`	`peekLast()` Retrieves, but does not remove, the last element of this deque, or returns `null` if this deque is empty.
`E`	`pollFirst()` Retrieves and removes the first element of this deque, or returns `null` if this deque is empty.
`E`	`pollLast()` Retrieves and removes the last element of this deque, or returns `null` if this deque is empty.
`E`	`pop()` Pops an element from the stack represented by this deque.
`void`	`push(E e)` Pushes an element onto the stack represented by this deque (in other words, at the head of this deque) if it is possible to do so immediately without violating capacity restrictions, throwing an `IllegalStateException` if no space is currently available.
`E`	`removeFirst()` Retrieves and removes the first element of this deque.
`boolean`	`removeFirstOccurrence(Object o)` Removes the first occurrence of the specified element from this deque.
`E`	`removeLast()` Retrieves and removes the last element of this deque.
`boolean`	`removeLastOccurrence(Object o)` Removes the last occurrence of the specified element from this deque.

Methods inherited from class com.google.common.collect.ForwardingQueue
element, offer, peek, poll, remove, standardOffer, standardPeek, standardPoll

Methods inherited from class com.google.common.collect.ForwardingCollection
add, addAll, clear, contains, containsAll, isEmpty, iterator, remove, removeAll, retainAll, size, standardAddAll, standardClear, standardContains, standardContainsAll, standardIsEmpty, standardRemove, standardRemoveAll, standardRetainAll, standardToArray, standardToArray, standardToString, toArray, toArray

Methods inherited from class com.google.common.collect.ForwardingObject
toString

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

Methods inherited from interface java.util.Deque
add, contains, element, iterator, offer, peek, poll, remove, remove, size

Methods inherited from interface java.util.Collection
addAll, clear, containsAll, equals, hashCode, isEmpty, parallelStream, removeAll, removeIf, retainAll, spliterator, stream, toArray, toArray

Methods inherited from interface java.lang.Iterable
forEach

- Constructor Detail
  - ForwardingDeque
```
protected ForwardingDeque()
```
    Constructor for use by subclasses.
- Method Detail
  - delegate
```
protected abstract Deque<E> delegate()
```
    Description copied from class: ForwardingObject
    
    Returns the backing delegate instance that methods are forwarded to. Abstract subclasses generally override this method with an abstract method that has a more specific return type, such as ForwardingSet.delegate(). Concrete subclasses override this method to supply the instance being decorated.
    
    Specified by:
    
    delegate in class ForwardingQueue<E>
  - addFirst
```
public void addFirst(E e)
```
    Description copied from interface: java.util.Deque
    
    Inserts the specified element at the front of this deque if it is possible to do so immediately without violating capacity restrictions, throwing an IllegalStateException if no space is currently available. When using a capacity-restricted deque, it is generally preferable to use method Deque.offerFirst(E).
    
    Specified by:
    
    addFirst in interface Deque<E>
    
    Parameters:
    
    e - the element to add
  - addLast
```
public void addLast(E e)
```
    Description copied from interface: java.util.Deque
    
    Inserts the specified element at the end of this deque if it is possible to do so immediately without violating capacity restrictions, throwing an IllegalStateException if no space is currently available. When using a capacity-restricted deque, it is generally preferable to use method Deque.offerLast(E).
    This method is equivalent to Deque.add(E).
    
    Specified by:
    
    addLast in interface Deque<E>
    
    Parameters:
    
    e - the element to add
  - descendingIterator
```
public Iterator<E> descendingIterator()
```
    Description copied from interface: java.util.Deque
    
    Returns an iterator over the elements in this deque in reverse sequential order. The elements will be returned in order from last (tail) to first (head).
    
    Specified by:
    
    descendingIterator in interface Deque<E>
    
    Returns:
    
    an iterator over the elements in this deque in reverse sequence
  - getFirst
```
public E getFirst()
```
    Description copied from interface: java.util.Deque
    
    Retrieves, but does not remove, the first element of this deque. This method differs from peekFirst only in that it throws an exception if this deque is empty.
    
    Specified by:
    
    getFirst in interface Deque<E>
    
    Returns:
    
    the head of this deque
  - getLast
```
public E getLast()
```
    Description copied from interface: java.util.Deque
    
    Retrieves, but does not remove, the last element of this deque. This method differs from peekLast only in that it throws an exception if this deque is empty.
    
    Specified by:
    
    getLast in interface Deque<E>
    
    Returns:
    
    the tail of this deque
  - offerFirst
```
public boolean offerFirst(E e)
```
    Description copied from interface: java.util.Deque
    
    Inserts the specified element at the front of this deque unless it would violate capacity restrictions. When using a capacity-restricted deque, this method is generally preferable to the Deque.addFirst(E) method, which can fail to insert an element only by throwing an exception.
    
    Specified by:
    
    offerFirst in interface Deque<E>
    
    Parameters:
    
    e - the element to add
    
    Returns:
    
    true if the element was added to this deque, else false
  - offerLast
```
public boolean offerLast(E e)
```
    Description copied from interface: java.util.Deque
    
    Inserts the specified element at the end of this deque unless it would violate capacity restrictions. When using a capacity-restricted deque, this method is generally preferable to the Deque.addLast(E) method, which can fail to insert an element only by throwing an exception.
    
    Specified by:
    
    offerLast in interface Deque<E>
    
    Parameters:
    
    e - the element to add
    
    Returns:
    
    true if the element was added to this deque, else false
  - peekFirst
```
public E peekFirst()
```
    Description copied from interface: java.util.Deque
    
    Retrieves, but does not remove, the first element of this deque, or returns null if this deque is empty.
    
    Specified by:
    
    peekFirst in interface Deque<E>
    
    Returns:
    
    the head of this deque, or null if this deque is empty
  - peekLast
```
public E peekLast()
```
    Description copied from interface: java.util.Deque
    
    Retrieves, but does not remove, the last element of this deque, or returns null if this deque is empty.
    
    Specified by:
    
    peekLast in interface Deque<E>
    
    Returns:
    
    the tail of this deque, or null if this deque is empty
  - pollFirst
```
public E pollFirst()
```
    Description copied from interface: java.util.Deque
    
    Retrieves and removes the first element of this deque, or returns null if this deque is empty.
    
    Specified by:
    
    pollFirst in interface Deque<E>
    
    Returns:
    
    the head of this deque, or null if this deque is empty
  - pollLast
```
public E pollLast()
```
    Description copied from interface: java.util.Deque
    
    Retrieves and removes the last element of this deque, or returns null if this deque is empty.
    
    Specified by:
    
    pollLast in interface Deque<E>
    
    Returns:
    
    the tail of this deque, or null if this deque is empty
  - pop
```
public E pop()
```
    Description copied from interface: java.util.Deque
    
    Pops an element from the stack represented by this deque. In other words, removes and returns the first element of this deque.
    This method is equivalent to Deque.removeFirst().
    
    Specified by:
    
    pop in interface Deque<E>
    
    Returns:
    
    the element at the front of this deque (which is the top of the stack represented by this deque)
  - push
```
public void push(E e)
```
    Description copied from interface: java.util.Deque
    
    Pushes an element onto the stack represented by this deque (in other words, at the head of this deque) if it is possible to do so immediately without violating capacity restrictions, throwing an IllegalStateException if no space is currently available.
    This method is equivalent to Deque.addFirst(E).
    
    Specified by:
    
    push in interface Deque<E>
    
    Parameters:
    
    e - the element to push
  - removeFirst
```
public E removeFirst()
```
    Description copied from interface: java.util.Deque
    
    Retrieves and removes the first element of this deque. This method differs from pollFirst only in that it throws an exception if this deque is empty.
    
    Specified by:
    
    removeFirst in interface Deque<E>
    
    Returns:
    
    the head of this deque
  - removeLast
```
public E removeLast()
```
    Description copied from interface: java.util.Deque
    
    Retrieves and removes the last element of this deque. This method differs from pollLast only in that it throws an exception if this deque is empty.
    
    Specified by:
    
    removeLast in interface Deque<E>
    
    Returns:
    
    the tail of this deque
  - removeFirstOccurrence
```
public boolean removeFirstOccurrence(Object o)
```
    Description copied from interface: java.util.Deque
    
    Removes the first occurrence of the specified element from this deque. If the deque does not contain the element, it is unchanged. More formally, removes the first element e such that (o==null ? e==null : o.equals(e)) (if such an element exists). Returns true if this deque contained the specified element (or equivalently, if this deque changed as a result of the call).
    
    Specified by:
    
    removeFirstOccurrence in interface Deque<E>
    
    Parameters:
    
    o - element to be removed from this deque, if present
    
    Returns:
    
    true if an element was removed as a result of this call
  - removeLastOccurrence
```
public boolean removeLastOccurrence(Object o)
```
    Description copied from interface: java.util.Deque
    
    Removes the last occurrence of the specified element from this deque. If the deque does not contain the element, it is unchanged. More formally, removes the last element e such that (o==null ? e==null : o.equals(e)) (if such an element exists). Returns true if this deque contained the specified element (or equivalently, if this deque changed as a result of the call).
    
    Specified by:
    
    removeLastOccurrence in interface Deque<E>
    
    Parameters:
    
    o - element to be removed from this deque, if present
    
    Returns:
    
    true if an element was removed as a result of this call

Class ForwardingDeque<E>

Constructor Summary

Method Summary

Methods inherited from class com.google.common.collect.ForwardingQueue

Methods inherited from class com.google.common.collect.ForwardingCollection

Methods inherited from class com.google.common.collect.ForwardingObject

Methods inherited from class java.lang.Object

Methods inherited from interface java.util.Deque

Methods inherited from interface java.util.Collection

Methods inherited from interface java.lang.Iterable

Constructor Detail

ForwardingDeque

Method Detail

delegate

addFirst

addLast

descendingIterator

getFirst

getLast

offerFirst

offerLast

peekFirst

peekLast

pollFirst

pollLast

pop

push

removeFirst

removeLast

removeFirstOccurrence

removeLastOccurrence