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java.lang.Objectjava.util.AbstractCollection<E>
com.espertech.esper.collection.ArrayDequeJDK6Backport<E>
E
- the type of elements held in this collectionpublic class ArrayDequeJDK6Backport<E>
Backport of the JDK6 ArrayDeque class as from the Sun source distribution of JDK 1.6.0_3.
Faster for adding, removing and iterating over elements when compared to LinkedList.
More expensive for toArray() then LinkedList.
Slightly more expensive for construction then LinkedList.
Resizable-array implementation of the JDK6 Deque interface. Array
deques have no capacity restrictions; they grow as necessary to support
usage. They are not thread-safe; in the absence of external
synchronization, they do not support concurrent access by multiple threads.
Null elements are prohibited. This class is likely to be faster than
Stack
when used as a stack, and faster than LinkedList
when used as a queue.
Most ArrayDeque operations run in amortized constant time.
Exceptions include remove
, removeFirstOccurrence
, removeLastOccurrence
, contains
, iterator.remove()
, and the bulk operations, all of which run in linear
time.
The iterators returned by this class's iterator method are
fail-fast: If the deque is modified at any time after the iterator
is created, in any way except through the iterator's own remove
method, the iterator will generally throw a ConcurrentModificationException
. Thus, in the face of concurrent
modification, the iterator fails quickly and cleanly, rather than risking
arbitrary, non-deterministic behavior at an undetermined time in the
future.
Note that the fail-fast behavior of an iterator cannot be guaranteed as it is, generally speaking, impossible to make any hard guarantees in the presence of unsynchronized concurrent modification. Fail-fast iterators throw ConcurrentModificationException on a best-effort basis. Therefore, it would be wrong to write a program that depended on this exception for its correctness: the fail-fast behavior of iterators should be used only to detect bugs.
This class and its iterator implement all of the
optional methods of the Collection
and Iterator
interfaces.
This class is a member of the Java Collections Framework.
Constructor Summary | |
---|---|
ArrayDequeJDK6Backport()
Constructs an empty array deque with an initial capacity sufficient to hold 16 elements. |
|
ArrayDequeJDK6Backport(Collection<? extends E> c)
Constructs a deque containing the elements of the specified collection, in the order they are returned by the collection's iterator. |
|
ArrayDequeJDK6Backport(int numElements)
Constructs an empty array deque with an initial capacity sufficient to hold the specified number of elements. |
Method Summary | ||
---|---|---|
boolean |
add(E e)
Inserts the specified element at the end of this deque. |
|
void |
addFirst(E e)
Inserts the specified element at the front of this deque. |
|
void |
addLast(E e)
Inserts the specified element at the end of this deque. |
|
void |
clear()
Removes all of the elements from this deque. |
|
boolean |
contains(Object o)
Returns true if this deque contains the specified element. |
|
Iterator<E> |
descendingIterator()
See equivalent Queue API method. |
|
E |
element()
Retrieves, but does not remove, the head of the queue represented by this deque. |
|
E |
getFirst()
See equivalent Queue API method. |
|
E |
getLast()
See equivalent Queue API method. |
|
boolean |
isEmpty()
Returns true if this deque contains no elements. |
|
Iterator<E> |
iterator()
Returns an iterator over the elements in this deque. |
|
boolean |
offer(E e)
Inserts the specified element at the end of this deque. |
|
boolean |
offerFirst(E e)
Inserts the specified element at the front of this deque. |
|
boolean |
offerLast(E e)
Inserts the specified element at the end of this deque. |
|
E |
peek()
Retrieves, but does not remove, the head of the queue represented by this deque, or returns null if this deque is empty. |
|
E |
peekFirst()
See equivalent Queue API method. |
|
E |
peekLast()
See equivalent Queue API method. |
|
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. |
|
E |
pollFirst()
See equivalent Queue API method. |
|
E |
pollLast()
See equivalent Queue API method. |
|
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. |
|
E |
remove()
Retrieves and removes the head of the queue represented by this deque. |
|
boolean |
remove(Object o)
Removes a single instance of the specified element from this deque. |
|
E |
removeFirst()
|
|
boolean |
removeFirstOccurrence(Object o)
Removes the first occurrence of the specified element in this deque (when traversing the deque from head to tail). |
|
E |
removeLast()
|
|
boolean |
removeLastOccurrence(Object o)
Removes the last occurrence of the specified element in this deque (when traversing the deque from head to tail). |
|
int |
size()
Returns the number of elements in this deque. |
|
Object[] |
toArray()
Returns an array containing all of the elements in this deque in proper sequence (from first to last element). |
|
|
toArray(T[] a)
Returns an array containing all of the elements in this deque in proper sequence (from first to last element); the runtime type of the returned array is that of the specified array. |
Methods inherited from class java.util.AbstractCollection |
---|
addAll, containsAll, removeAll, retainAll, 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 |
---|
equals, hashCode |
Constructor Detail |
---|
public ArrayDequeJDK6Backport()
public ArrayDequeJDK6Backport(int numElements)
numElements
- lower bound on initial capacity of the dequepublic ArrayDequeJDK6Backport(Collection<? extends E> c)
c
- the collection whose elements are to be placed into the deque
NullPointerException
- if the specified collection is nullMethod Detail |
---|
public void addFirst(E e)
e
- the element to add
NullPointerException
- if the specified element is nullpublic void addLast(E e)
This method is equivalent to add(E)
.
e
- the element to add
NullPointerException
- if the specified element is nullpublic boolean offerFirst(E e)
e
- the element to add
NullPointerException
- if the specified element is nullpublic boolean offerLast(E e)
e
- the element to add
NullPointerException
- if the specified element is nullpublic E removeFirst()
NoSuchElementException
- no more elementspublic E removeLast()
NoSuchElementException
- no more elementspublic E pollFirst()
public E pollLast()
public E getFirst()
NoSuchElementException
- no more elementspublic E getLast()
NoSuchElementException
- no more elementspublic E peekFirst()
public E peekLast()
public boolean removeFirstOccurrence(Object o)
o
- element to be removed from this deque, if present
public boolean removeLastOccurrence(Object o)
o
- element to be removed from this deque, if present
public boolean add(E e)
This method is equivalent to addLast(E)
.
add
in interface Collection<E>
add
in class AbstractCollection<E>
e
- the element to add
Collection.add(E)
)
NullPointerException
- if the specified element is nullpublic boolean offer(E e)
This method is equivalent to offerLast(E)
.
e
- the element to add
Queue.offer(E)
)
NullPointerException
- if the specified element is nullpublic E remove()
poll
only in that it throws an
exception if this deque is empty.
This method is equivalent to removeFirst()
.
NoSuchElementException
- no more elementspublic E poll()
This method is equivalent to pollFirst()
.
public E element()
peek
only in
that it throws an exception if this deque is empty.
This method is equivalent to getFirst()
.
NoSuchElementException
- no more elementspublic E peek()
This method is equivalent to peekFirst()
.
public void push(E e)
This method is equivalent to addFirst(E)
.
e
- the element to push
NullPointerException
- if the specified element is nullpublic E pop()
This method is equivalent to removeFirst()
.
NoSuchElementException
- no more elementspublic int size()
size
in interface Collection<E>
size
in class AbstractCollection<E>
public boolean isEmpty()
isEmpty
in interface Collection<E>
isEmpty
in class AbstractCollection<E>
public Iterator<E> iterator()
remove()
or popped (via successive calls to pop()
).
iterator
in interface Iterable<E>
iterator
in interface Collection<E>
iterator
in class AbstractCollection<E>
public Iterator<E> descendingIterator()
public boolean contains(Object o)
contains
in interface Collection<E>
contains
in class AbstractCollection<E>
o
- object to be checked for containment in this deque
public boolean remove(Object o)
This method is equivalent to removeFirstOccurrence(java.lang.Object)
.
remove
in interface Collection<E>
remove
in class AbstractCollection<E>
o
- element to be removed from this deque, if present
public void clear()
clear
in interface Collection<E>
clear
in class AbstractCollection<E>
public Object[] toArray()
The returned array will be "safe" in that no references to it are maintained by this deque. (In other words, this method must allocate a new array). The caller is thus free to modify the returned array.
This method acts as bridge between array-based and collection-based APIs.
toArray
in interface Collection<E>
toArray
in class AbstractCollection<E>
public <T> T[] toArray(T[] a)
If this deque fits in the specified array with room to spare (i.e., the array has more elements than this deque), the element in the array immediately following the end of the deque is set to null.
Like the toArray()
method, this method acts as bridge between
array-based and collection-based APIs. Further, this method allows
precise control over the runtime type of the output array, and may,
under certain circumstances, be used to save allocation costs.
Suppose x is a deque known to contain only strings. The following code can be used to dump the deque into a newly allocated array of String:
String[] y = x.toArray(new String[0]);Note that toArray(new Object[0]) is identical in function to toArray().
toArray
in interface Collection<E>
toArray
in class AbstractCollection<E>
a
- the array into which the elements of the deque are to
be stored, if it is big enough; otherwise, a new array of the
same runtime type is allocated for this purpose
ArrayStoreException
- if the runtime type of the specified array
is not a supertype of the runtime type of every element in
this deque
NullPointerException
- if the specified array is null
|
© 2007 EsperTech Inc. All rights reserved. Visit us at espertech.com |
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