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=====ConcurrentLinkedQueue class=====
The <code>java.util.concurrent.ConcurrentLinkedQueue</code> class extends {{java|java.util.AbstractQueue}}. <code>ConcurrentLinkedQueue</code> implements the {{java|java.util.Queue}} interface.{{sfn|Goetz|Peierls|Bloch|Bowbeer|2006|loc=§5.2 Concurrent collections|pp=84-85}}
The {{java|<code>ConcurrentLinkedQueue}}</code> class is a thread-safe collection, since for any an element placed inside a {{java|ConcurrentLinkedQueue}}, the Java Collection Library guarantees that the element is ''safely published'' by allowing any thread to get the element from the collection.{{sfn|Goetz|Peierls|Bloch|Bowbeer|2006|loc=§3.5.3 Safe publication idioms|pp=52-53}} An object is said to be ''safely published'' if the object's state is made visible to all other thread at the same point in time.{{sfn|Goetz|Peierls|Bloch|Bowbeer|2006|loc=§3.5.3 Safe publication idioms|pp=52-53}} Safe publication usually requires synchronization of the publishing and consuming threads.{{sfn|Goetz|Peierls|Bloch|Bowbeer|2006|loc=§3.5.3 Safe publication idioms|pp=52-53}}
===BlockingQueue interface===
The
'''{{Javadoc|module=java.base|package=java.util.concurrent|class=BlockingQueue|monotype=y}}''' interface extends <code>Queue</code>,.{{sfn|Goetz|Peierls|Bloch|Bowbeer|2006|loc=§5.2 Concurrent collections|pp=84-85}} and can be used more flexibly.
The {{java|BlockingQueue}} interface has the following direct sub-interfaces: {{java|BlockingDeque}} and {{java|TransferQueue}}. {{java|BlockingQueue}} works like a regular <code>Queue</code>, but additions to and removals from the <code>BlockingQueue</code> are blocking.{{sfn|Bloch|2018|loc=Chapter §11 Item 78: Synchronize access to shared mutable data|pp=325-329}} If
{{java|BlockingQueue}} works like a regular <code>Queue</code>, but additions to and removals from the <code>BlockingQueue</code> are blocking.{{sfn|Bloch|2018|loc=Chapter §11 Item 78: Synchronize access to shared mutable data|pp=325-329}} If
{{Javadoc|module=java.base|package=java.util|class=Queue|member=remove(java.lang.Object)|text=remove(Object o)|monotype=y}} is called on an empty <code>BlockingQueue</code>, it can be set to wait either a specified time or indefinitely for an item to appear in the <code>BlockingQueue</code>. Similarly, adding an item using the method {{Javadoc|module=java.base|package=java.util|class=Queue|member=add(java.lang.Object)|text=add(Object o)|monotype=y}} is subject to an optional capacity restriction on the <code>BlockingQueue</code>, and the method can wait for space to become available in the <code>BlockingQueue</code> before returning. <code>BlockingQueue</code> interface introduces a method {{Javadoc|module=java.base|package=java.util|class=BlockingQueue|member=take()|text=take()|monotype=y}} which removes and gets the head of the <code>BlockingQueue</code>, and waits until the <code>BlockingQueue</code> is no longer empty if required.<ref>{{cite web|url=http://docs.oracle.com/javase/7/docs/api/java/util/concurrent/BlockingQueue.html |title=BlockingQueue (Java Platform SE 7) |publisher=Docs.oracle.com |date=2013-06-06 |access-date=2013-08-16}}</ref>{{sfn|Bloch|2018|loc=Chapter §11 Item 81: Prefer concurrency utilities to wait and notify|pp=325-329}}
===Double-ended queue (Deque) interfaces===
The {{java|<code>java.util.Deque}} interface extends the {{java|Queue}}</code> interface. {{sfn|Goetz|Peierls|Bloch|Bowbeer|2006|loc=§5.3.3is Dequesexpanded andby workthe stealing|p=92}}{{java|<code>java.util.Deque}}</code> subinterface. <code>Deque</code> creates a double-ended queue. While a regular <code>Queue</code> only allows insertions at the rear and removals at the front, the {{java|<code>Deque}}</code> allows insertions or removals to take place both at the front and the back. A <code>Deque</code> is like a <code>Queue</code> that can be used forwards or backwards, or both at once. Additionally, both a forwards and a backwards iterator can be generated. The {{java|<code>Deque}}</code> interface is implemented by <code>java.util.ArrayDeque</code> and <code>java.util.LinkedList</code>.<ref>{{cite web|url=http://docs.oracle.com/javase/7/docs/api/java/util/Deque.html |title=Deque (Java Platform SE 7 ) |publisher=Docs.oracle.com |date=2013-06-06 |access-date=2013-08-16}}</ref>
====Deque implementations====
<code>ArrayDeque</code> implements the <code>Queue</code> as an array. Similar to <code>LinkedList</code>, <code>ArrayDeque</code> also implements the '''{{Javadoc|module=java.base|package=java.util|class=Deque|monotype=y}}''' interface.<ref>{{cite web|url=http://docs.oracle.com/javase/7/docs/api/java/util/Queue.html |title=Queue (Java Platform SE 7) |publisher=Docs.oracle.com |date=2013-06-06 |access-date=2013-08-16}}</ref>
====BlockingDeque interface====
The '''{{Javadoc:SE|module=java.base|package=java.util.concurrent|java/util/concurrent|BlockingDeque}}''' extendsinterface theworks similarly to <code>java.util.concurrent.BlockingQueue</code>. The same methods for insertion and removal with time limits for waiting for the insertion or removal to become possible are provided. However, the interface also provides the flexibility of a <code>Deque</code>. Insertions and removals can take place at both ends. The blocking function is combined with the <code>Deque</code> function.<ref>{{cite web|url=http://docs.oracle.com/javase/7/docs/api/java/util/concurrent/BlockingDeque.html |title=BlockingDeque (Java Platform SE 7 ) |publisher=Docs.oracle.com |date=2013-06-06 |access-date=2013-08-16}}</ref>
The {{java|BlockingDeque}} interface works similarly to {{java|BlockingQueue}}. The same methods for insertion and removal with time limits for waiting for the insertion or removal to become possible are provided. However, the interface also provides the flexibility of a {{java|Deque}}. Insertions and removals can take place at both ends. The blocking function is combined with the <code>Deque</code> function.<ref>{{cite web|url=http://docs.oracle.com/javase/7/docs/api/java/util/concurrent/BlockingDeque.html |title=BlockingDeque (Java Platform SE 7 ) |publisher=Docs.oracle.com |date=2013-06-06 |access-date=2013-08-16}}</ref>
==Set interfaces==
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