File	Doc	Category	Size	Date	Package
Deque.java	API Doc	Java SE 6 API	22127	Tue Jun 10 00:25:52 BST 2008	java.util

Deque

Fields Summary

Constructors Summary

Methods Summary
public boolean	add(E e) Inserts the specified element into the queue represented by this deque (in other words, at the tail of this deque) if it is possible to do so immediately without violating capacity restrictions, returning true upon success and throwing an IllegalStateException if no space is currently available. When using a capacity-restricted deque, it is generally preferable to use {@link #offer(Object) offer}. This method is equivalent to {@link #addLast}. param e the element to add return true (as specified by {@link Collection#add}) throws IllegalStateException if the element cannot be added at this time due to capacity restrictions throws ClassCastException if the class of the specified element prevents it from being added to this deque throws NullPointerException if the specified element is null and this deque does not permit null elements throws IllegalArgumentException if some property of the specified element prevents it from being added to this deque
public 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. When using a capacity-restricted deque, it is generally preferable to use method {@link #offerFirst}. param e the element to add throws IllegalStateException if the element cannot be added at this time due to capacity restrictions throws ClassCastException if the class of the specified element prevents it from being added to this deque throws NullPointerException if the specified element is null and this deque does not permit null elements throws IllegalArgumentException if some property of the specified element prevents it from being added to this deque
public 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. When using a capacity-restricted deque, it is generally preferable to use method {@link #offerLast}. This method is equivalent to {@link #add}. param e the element to add throws IllegalStateException if the element cannot be added at this time due to capacity restrictions throws ClassCastException if the class of the specified element prevents it from being added to this deque throws NullPointerException if the specified element is null and this deque does not permit null elements throws IllegalArgumentException if some property of the specified element prevents it from being added to this deque
public boolean	contains(java.lang.Object o) Returns true if this deque contains the specified element. More formally, returns true if and only if this deque contains at least one element e such that (o==null ? e==null : o.equals(e)). param o element whose presence in this deque is to be tested return true if this deque contains the specified element throws ClassCastException if the type of the specified element is incompatible with this deque (optional) throws NullPointerException if the specified element is null and this deque does not permit null elements (optional)
public java.util.Iterator	descendingIterator() 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). return an iterator over the elements in this deque in reverse sequence
public E	element() Retrieves, but does not remove, the head of the queue represented by this deque (in other words, the first element of this deque). This method differs from {@link #peek peek} only in that it throws an exception if this deque is empty. This method is equivalent to {@link #getFirst()}. return the head of the queue represented by this deque throws NoSuchElementException if this deque is empty
public E	getFirst() Retrieves, but does not remove, the first element of this deque. This method differs from {@link #peekFirst peekFirst} only in that it throws an exception if this deque is empty. return the head of this deque throws NoSuchElementException if this deque is empty
public E	getLast() Retrieves, but does not remove, the last element of this deque. This method differs from {@link #peekLast peekLast} only in that it throws an exception if this deque is empty. return the tail of this deque throws NoSuchElementException if this deque is empty
public java.util.Iterator	iterator() Returns an iterator over the elements in this deque in proper sequence. The elements will be returned in order from first (head) to last (tail). return an iterator over the elements in this deque in proper sequence
public boolean	offer(E e) Inserts the specified element into the queue represented by this deque (in other words, at the tail of this deque) if it is possible to do so immediately without violating capacity restrictions, returning true upon success and false if no space is currently available. When using a capacity-restricted deque, this method is generally preferable to the {@link #add} method, which can fail to insert an element only by throwing an exception. This method is equivalent to {@link #offerLast}. param e the element to add return true if the element was added to this deque, else false throws ClassCastException if the class of the specified element prevents it from being added to this deque throws NullPointerException if the specified element is null and this deque does not permit null elements throws IllegalArgumentException if some property of the specified element prevents it from being added to this deque
public boolean	offerFirst(E e) 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 {@link #addFirst} method, which can fail to insert an element only by throwing an exception. param e the element to add return true if the element was added to this deque, else false throws ClassCastException if the class of the specified element prevents it from being added to this deque throws NullPointerException if the specified element is null and this deque does not permit null elements throws IllegalArgumentException if some property of the specified element prevents it from being added to this deque
public boolean	offerLast(E e) 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 {@link #addLast} method, which can fail to insert an element only by throwing an exception. param e the element to add return true if the element was added to this deque, else false throws ClassCastException if the class of the specified element prevents it from being added to this deque throws NullPointerException if the specified element is null and this deque does not permit null elements throws IllegalArgumentException if some property of the specified element prevents it from being added to this deque
public E	peek() Retrieves, but does not remove, the head of the queue represented by this deque (in other words, the first element of this deque), or returns null if this deque is empty. This method is equivalent to {@link #peekFirst()}. return the head of the queue represented by this deque, or null if this deque is empty
public E	peekFirst() Retrieves, but does not remove, the first element of this deque, or returns null if this deque is empty. return the head of this deque, or null if this deque is empty
public E	peekLast() Retrieves, but does not remove, the last element of this deque, or returns null if this deque is empty. return the tail of this deque, or null if this deque is empty
public E	poll() Retrieves and removes the head of the queue represented by this deque (in other words, the first element of this deque), or returns null if this deque is empty. This method is equivalent to {@link #pollFirst()}. return the first element of this deque, or null if this deque is empty
public E	pollFirst() Retrieves and removes the first element of this deque, or returns null if this deque is empty. return the head of this deque, or null if this deque is empty
public E	pollLast() Retrieves and removes the last element of this deque, or returns null if this deque is empty. return the tail of this deque, or null if this deque is empty
public E	pop() 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 {@link #removeFirst()}. return the element at the front of this deque (which is the top of the stack represented by this deque) throws NoSuchElementException if this deque is empty
public 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, returning true upon success and throwing an IllegalStateException if no space is currently available. This method is equivalent to {@link #addFirst}. param e the element to push throws IllegalStateException if the element cannot be added at this time due to capacity restrictions throws ClassCastException if the class of the specified element prevents it from being added to this deque throws NullPointerException if the specified element is null and this deque does not permit null elements throws IllegalArgumentException if some property of the specified element prevents it from being added to this deque
public E	remove() Retrieves and removes the head of the queue represented by this deque (in other words, the first element of this deque). This method differs from {@link #poll poll} only in that it throws an exception if this deque is empty. This method is equivalent to {@link #removeFirst()}. return the head of the queue represented by this deque throws NoSuchElementException if this deque is empty
public boolean	remove(java.lang.Object o) 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). This method is equivalent to {@link #removeFirstOccurrence}. param o element to be removed from this deque, if present return true if an element was removed as a result of this call throws ClassCastException if the class of the specified element is incompatible with this deque (optional) throws NullPointerException if the specified element is null and this deque does not permit null elements (optional)
public E	removeFirst() Retrieves and removes the first element of this deque. This method differs from {@link #pollFirst pollFirst} only in that it throws an exception if this deque is empty. return the head of this deque throws NoSuchElementException if this deque is empty
public boolean	removeFirstOccurrence(java.lang.Object o) 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). param o element to be removed from this deque, if present return true if an element was removed as a result of this call throws ClassCastException if the class of the specified element is incompatible with this deque (optional) throws NullPointerException if the specified element is null and this deque does not permit null elements (optional)
public E	removeLast() Retrieves and removes the last element of this deque. This method differs from {@link #pollLast pollLast} only in that it throws an exception if this deque is empty. return the tail of this deque throws NoSuchElementException if this deque is empty
public boolean	removeLastOccurrence(java.lang.Object o) 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). param o element to be removed from this deque, if present return true if an element was removed as a result of this call throws ClassCastException if the class of the specified element is incompatible with this deque (optional) throws NullPointerException if the specified element is null and this deque does not permit null elements (optional)
public int	size() Returns the number of elements in this deque. return the number of elements in this deque