Java Doc for ConcurrentLinkedQueue.java in  » 6.0-JDK-Core » Collections-Jar-Zip-Logging-regex » java » util » concurrent » Java Source Code / Java DocumentationJava Source Code and Java Documentation

Home
Java Source Code / Java Documentation
1.6.0 JDK Core
2.6.0 JDK Modules
3.6.0 JDK Modules com.sun
4.6.0 JDK Modules com.sun.java
5.6.0 JDK Modules sun
6.6.0 JDK Platform
7.Ajax
8.Apache Harmony Java SE
9.Aspect oriented
10.Authentication Authorization
11.Blogger System
12.Build
13.Byte Code
14.Cache
15.Chart
16.Chat
17.Code Analyzer
18.Collaboration
19.Content Management System
20.Database Client
21.Database DBMS
22.Database JDBC Connection Pool
23.Database ORM
24.Development
25.EJB Server
26.ERP CRM Financial
27.ESB
28.Forum
29.Game
30.GIS
31.Graphic 3D
32.Graphic Library
33.Groupware
34.HTML Parser
35.IDE
36.IDE Eclipse
37.IDE Netbeans
38.Installer
39.Internationalization Localization
40.Inversion of Control
41.Issue Tracking
42.J2EE
43.J2ME
44.JBoss
45.JMS
46.JMX
47.Library
48.Mail Clients
49.Music
50.Net
51.Parser
52.PDF
53.Portal
54.Profiler
55.Project Management
56.Report
57.RSS RDF
58.Rule Engine
59.Science
60.Scripting
61.Search Engine
62.Security
63.Sevlet Container
64.Source Control
65.Swing Library
66.Template Engine
67.Test Coverage
68.Testing
69.UML
70.Web Crawler
71.Web Framework
72.Web Mail
73.Web Server
74.Web Services
75.Web Services apache cxf 2.2.6
76.Web Services AXIS2
77.Wiki Engine
78.Workflow Engines
79.XML
80.XML UI
Java Source Code / Java Documentation » 6.0 JDK Core » Collections Jar Zip Logging regex » java.util.concurrent 
Source Cross Reference  Class Diagram Java Document (Java Doc) 


java.util.concurrent.ConcurrentLinkedQueue

ConcurrentLinkedQueue
public class ConcurrentLinkedQueue extends AbstractQueue implements Queue<E>,java.io.Serializable(Code)
An unbounded thread-safe based on linked nodes. This queue orders elements FIFO (first-in-first-out). The head of the queue is that element that has been on the queue the longest time. The tail of the queue is that element that has been on the queue the shortest time. New elements are inserted at the tail of the queue, and the queue retrieval operations obtain elements at the head of the queue. A ConcurrentLinkedQueue is an appropriate choice when many threads will share access to a common collection. This queue does not permit null elements.

This implementation employs an efficient "wait-free" algorithm based on one described in Simple, Fast, and Practical Non-Blocking and Blocking Concurrent Queue Algorithms by Maged M. Michael and Michael L. Scott.

Beware that, unlike in most collections, the size method is NOT a constant-time operation. Because of the asynchronous nature of these queues, determining the current number of elements requires a traversal of the elements.

This class and its iterator implement all of the optional methods of the Collection and Iterator interfaces.

Memory consistency effects: As with other concurrent collections, actions in a thread prior to placing an object into a ConcurrentLinkedQueue happen-before actions subsequent to the access or removal of that element from the ConcurrentLinkedQueue in another thread.

This class is a member of the Java Collections Framework.
since:
   1.5
author:
   Doug Lea<
Parameters:
  E - > the type of elements held in this collection




Constructor Summary
public  ConcurrentLinkedQueue()
     Creates a ConcurrentLinkedQueue that is initially empty.
public  ConcurrentLinkedQueue(Collection<? extends E> c)
     Creates a ConcurrentLinkedQueue initially containing the elements of the given collection, added in traversal order of the collection's iterator.

Method Summary
public  booleanadd(E e)
     Inserts the specified element at the tail of this queue.
public  booleancontains(Object o)
     Returns true if this queue contains the specified element.
 Node<E>first()
     Returns the first actual (non-header) node on list.
public  booleanisEmpty()
     Returns true if this queue contains no elements.
public  Iterator<E>iterator()
     Returns an iterator over the elements in this queue in proper sequence.
public  booleanoffer(E e)
     Inserts the specified element at the tail of this queue.
public  Epeek()
    
public  Epoll()
    
public  booleanremove(Object o)
     Removes a single instance of the specified element from this queue, if it is present.
public  intsize()
     Returns the number of elements in this queue.
public  Object[]toArray()
     Returns an array containing all of the elements in this queue, in proper sequence.

The returned array will be "safe" in that no references to it are maintained by this queue.

public  T[]toArray(T[] a)
     Returns an array containing all of the elements in this queue, in proper sequence; the runtime type of the returned array is that of the specified array.


Constructor Detail
ConcurrentLinkedQueue
public ConcurrentLinkedQueue()(Code)
Creates a ConcurrentLinkedQueue that is initially empty.



ConcurrentLinkedQueue
public ConcurrentLinkedQueue(Collection<? extends E> c)(Code)
Creates a ConcurrentLinkedQueue initially containing the elements of the given collection, added in traversal order of the collection's iterator.
Parameters:
  c - the collection of elements to initially contain
throws:
  NullPointerException - if the specified collection or anyof its elements are null




Method Detail
add
public boolean add(E e)(Code)
Inserts the specified element at the tail of this queue. true (as specified by Collection.add)
throws:
  NullPointerException - if the specified element is null



contains
public boolean contains(Object o)(Code)
Returns true if this queue contains the specified element. More formally, returns true if and only if this queue contains at least one element e such that o.equals(e).
Parameters:
  o - object to be checked for containment in this queue true if this queue contains the specified element



first
Node<E> first()(Code)
Returns the first actual (non-header) node on list. This is yet another variant of poll/peek; here returning out the first node, not element (so we cannot collapse with peek() without introducing race.)



isEmpty
public boolean isEmpty()(Code)
Returns true if this queue contains no elements. true if this queue contains no elements



iterator
public Iterator<E> iterator()(Code)
Returns an iterator over the elements in this queue in proper sequence. The returned iterator is a "weakly consistent" iterator that will never throw ConcurrentModificationException , and guarantees to traverse elements as they existed upon construction of the iterator, and may (but is not guaranteed to) reflect any modifications subsequent to construction. an iterator over the elements in this queue in proper sequence



offer
public boolean offer(E e)(Code)
Inserts the specified element at the tail of this queue. true (as specified by Queue.offer)
throws:
  NullPointerException - if the specified element is null



peek
public E peek()(Code)



poll
public E poll()(Code)



remove
public boolean remove(Object o)(Code)
Removes a single instance of the specified element from this queue, if it is present. More formally, removes an element e such that o.equals(e), if this queue contains one or more such elements. Returns true if this queue contained the specified element (or equivalently, if this queue changed as a result of the call).
Parameters:
  o - element to be removed from this queue, if present true if this queue changed as a result of the call



size
public int size()(Code)
Returns the number of elements in this queue. If this queue contains more than Integer.MAX_VALUE elements, returns Integer.MAX_VALUE.

Beware that, unlike in most collections, this method is NOT a constant-time operation. Because of the asynchronous nature of these queues, determining the current number of elements requires an O(n) traversal. the number of elements in this queue




toArray
public Object[] toArray()(Code)
Returns an array containing all of the elements in this queue, in proper sequence.

The returned array will be "safe" in that no references to it are maintained by this queue. (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. an array containing all of the elements in this queue




toArray
public T[] toArray(T[] a)(Code)
Returns an array containing all of the elements in this queue, in proper sequence; the runtime type of the returned array is that of the specified array. If the queue fits in the specified array, it is returned therein. Otherwise, a new array is allocated with the runtime type of the specified array and the size of this queue.

If this queue fits in the specified array with room to spare (i.e., the array has more elements than this queue), the element in the array immediately following the end of the queue is set to null.

Like the ConcurrentLinkedQueue.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 queue known to contain only strings. The following code can be used to dump the queue 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().
Parameters:
  a - the array into which the elements of the queue are tobe stored, if it is big enough; otherwise, a new array of thesame runtime type is allocated for this purpose an array containing all of the elements in this queue
throws:
  ArrayStoreException - if the runtime type of the specified arrayis not a supertype of the runtime type of every element inthis queue
throws:
  NullPointerException - if the specified array is null



www.java2java.com | Contact Us
Copyright 2009 - 12 Demo Source and Support. All rights reserved.
All other trademarks are property of their respective owners.