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edu.emory.mathcs.util.concurrent
Class DynamicArrayBlockingQueue  

java.lang.Object
  java.util.AbstractCollection
      edu.emory.mathcs.util.AbstractQueue
          edu.emory.mathcs.util.concurrent.DynamicArrayBlockingQueue

All Implemented Interfaces:

BlockingQueue, java.util.Collection, edu.emory.mathcs.util.Queue

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public class DynamicArrayBlockingQueue

extends edu.emory.mathcs.util.AbstractQueue

implements BlockingQueue

This class represents queue of objects. Data is generally stored at the bottom of the queue by put and related operations, and read from the top of the queue by take and related operations. The putAtHead family of operations is also provided to allow storing data at the head of the queue. The underlying implementation uses an array, so no memory allocation occur on queue operations apart from situations where array needs to be resized. The initial and maximum capacity of the queue can be specified at the construction time. The maximum capacity may be also set to "infinity", in which case put operations will never block.

Version:

1.0

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Field Summary
(package private)  int	beg
(package private)  java.lang.Object[]	buf
(package private)  int	end
(package private)  int	length
(package private)  int	maxcap

 

Constructor Summary

DynamicArrayBlockingQueue()           Creates new queue object with initial capacity of 16 and unlimited maximum capacity.

DynamicArrayBlockingQueue(int initcap)           Creates new queue object with specified initial capacity and unlimited maximum capacity.

DynamicArrayBlockingQueue(int initcap, int maxcap)           Creates new queue object with specified initial capacity and specified maximum capacity.

 

Method Summary
private  boolean	enlargeForPut()
private  boolean	enlargeForPutAtHead()
private  boolean	full()
java.util.Iterator	iterator()           Obtain an Iterator over this collection.
boolean	offer(java.lang.Object o)           Puts specified object at the bottom of the queue, if possible.
boolean	offer(java.lang.Object o, long timeout, TimeUnit granularity)           Puts specified object at the bottom of the queue with specified timeout and returns true if operation succeeded, false otherwise.
boolean	offerAtHead(java.lang.Object o)           Inserts specified object at the top of the queue, so the next call to get() would return this object.
boolean	offerAtHead(java.lang.Object o, int timeout, TimeUnit granularity)           Inserts specified object at the top of the queue, so the next call to get() would return this object, with specified timeout and returns true if operation succeeded, false otherwise.
java.lang.Object	peek()           Return, but do not remove, an element from the queue, or null if the queue is empty.
private  java.lang.Object	peek0()
java.lang.Object	poll()           Remove and return an element from the queue if one is available.
java.lang.Object	poll(long timeout, TimeUnit granularity)           Gets the object from the top of the queue.
void	put(java.lang.Object o)           Add the given object to the queue, waiting if necessary for space to become available.
private  void	put0(java.lang.Object o)
void	putAtHead(java.lang.Object o)           Inserts specified object at the top of the queue, so the next call to poll() or take() would return this object.
private  void	putAtHead0(java.lang.Object o)
int	remainingCapacity()           Return the number of elements that this queue can ideally (in the absence of memory or resource constraints) accept without blocking, or Integer.MAX_VALUE if there is no intrinsic limit.
int	size()           Returns the number of items in this queue.
java.lang.Object	take()           Retrieve and remove the first element from the queue, waiting if no objects are present on the queue.
private  java.lang.Object	take0()

 

Methods inherited from class edu.emory.mathcs.util.AbstractQueue

add, clear, element, remove

 

Methods inherited from class java.util.AbstractCollection

addAll, contains, containsAll, isEmpty, remove, removeAll, retainAll, toArray, toArray, toString

 

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

 

Methods inherited from interface edu.emory.mathcs.util.Queue

element, remove

 

Methods inherited from interface java.util.Collection

add, addAll, clear, contains, containsAll, equals, hashCode, isEmpty, remove, removeAll, retainAll, toArray, toArray

 

Field Detail

buf

java.lang.Object[] buf

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beg

int beg

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end

int end

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length

int length

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maxcap

int maxcap

Constructor Detail

DynamicArrayBlockingQueue

public DynamicArrayBlockingQueue()

Creates new queue object with initial capacity of 16 and unlimited maximum capacity.

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DynamicArrayBlockingQueue

public DynamicArrayBlockingQueue(int initcap)

Creates new queue object with specified initial capacity and unlimited maximum capacity. Initial capacity must be greater than 0, otherwise IllegalArgumentException will be thrown.

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DynamicArrayBlockingQueue

public DynamicArrayBlockingQueue(int initcap,
                                 int maxcap)

Creates new queue object with specified initial capacity and specified maximum capacity. Initial capacity must be greater than 0, otherwise IllegalArgumentException will be thrown. Maximum capacity of less than or equal to 0 indicates no limit. Otherwise if the maximum capacity is positive number, it has to be greater than or equal to initial capacity, or IllegalArgumentException will be thrown.

Method Detail

size

public int size()

Returns the number of items in this queue.

Specified by:

size in interface java.util.Collection

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remainingCapacity

public int remainingCapacity()

Description copied from interface: BlockingQueue

Return the number of elements that this queue can ideally (in the absence of memory or resource constraints) accept without blocking, or Integer.MAX_VALUE if there is no intrinsic limit. Note that you cannot always tell if an attempt to add an element will succeed by inspecting remainingCapacity because it may be the case that a waiting consumer is ready to take an element out of an otherwise full queue.

Specified by:

remainingCapacity in interface BlockingQueue

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iterator

public java.util.Iterator iterator()

Description copied from interface: java.util.Collection

Obtain an Iterator over this collection.

Specified by:

iterator in interface java.util.Collection

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offer

public boolean offer(java.lang.Object o)

Puts specified object at the bottom of the queue, if possible.

Specified by:

offer in interface edu.emory.mathcs.util.Queue

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offer

public boolean offer(java.lang.Object o,
                     long timeout,
                     TimeUnit granularity)
              throws java.lang.InterruptedException

Puts specified object at the bottom of the queue with specified timeout and returns true if operation succeeded, false otherwise. If the length of the queue is equal to its maximum capacity, this method will block until either the length decreases (in which case it proceeds with put and returns true) or timeout expires (in which case it returns false), whichever comes first. If the timeout is a positive number, it indicates a number of milliseconds to wait for available space. If the timeout is equal to 0 and the queue is full, the method will immediately return false. If the timeout is negative, the method will never timeout.

Specified by:

offer in interface BlockingQueue

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put

public void put(java.lang.Object o)
         throws java.lang.InterruptedException

Description copied from interface: BlockingQueue

Add the given object to the queue, waiting if necessary for space to become available.

Specified by:

put in interface BlockingQueue

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offerAtHead

public boolean offerAtHead(java.lang.Object o)

Inserts specified object at the top of the queue, so the next call to get() would return this object.

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putAtHead

public void putAtHead(java.lang.Object o)
               throws java.lang.InterruptedException

Inserts specified object at the top of the queue, so the next call to poll() or take() would return this object. If the length of the queue is equal to its maximum capacity, this method will block until the length decreases so that the operation can proceed.

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offerAtHead

public boolean offerAtHead(java.lang.Object o,
                           int timeout,
                           TimeUnit granularity)
                    throws java.lang.InterruptedException

Inserts specified object at the top of the queue, so the next call to get() would return this object, with specified timeout and returns true if operation succeeded, false otherwise. If the length of the queue is equal to its maximum capacity, this method will block until either the length decreases (in which case it proceeds with insert and returns true) or timeout expires (in which case it returns false), whichever comes first. If the timeout is a positive number, it indicates a number of milliseconds to wait for available space. If the timeout is equal to 0 and the queue is full, the method will immediately return false. If the timeout is negative, the method will never timeout.

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take

public java.lang.Object take()
                      throws java.lang.InterruptedException

Retrieve and remove the first element from the queue, waiting if no objects are present on the queue.

Specified by:

take in interface BlockingQueue

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poll

public java.lang.Object poll(long timeout,
                             TimeUnit granularity)
                      throws java.lang.InterruptedException

Gets the object from the top of the queue. If the queue is empty, this method will block until either the length increases (in which case it proceeds with get) or timeout expires (in which case it returns null), whichever comes first. If the timeout is a positive number, it indicates a number of milliseconds to wait. If the timeout is equal to 0 and the queue is empty, the method will immediately return null. If the timeout is negative, the method will never timeout.

Specified by:

poll in interface BlockingQueue

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peek

public java.lang.Object peek()

Description copied from interface: edu.emory.mathcs.util.Queue

Return, but do not remove, an element from the queue, or null if the queue is empty. This method returns the same object reference that would be returned by by the poll method. The two methods differ in that this method does not remove the element from the queue.

Specified by:

peek in interface edu.emory.mathcs.util.Queue

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poll

public java.lang.Object poll()

Remove and return an element from the queue if one is available.

Specified by:

poll in interface edu.emory.mathcs.util.Queue

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take0

private java.lang.Object take0()

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peek0

private java.lang.Object peek0()

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put0

private void put0(java.lang.Object o)

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putAtHead0

private void putAtHead0(java.lang.Object o)

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enlargeForPut

private boolean enlargeForPut()

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enlargeForPutAtHead

private boolean enlargeForPutAtHead()

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full

private boolean full()

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Home >> All >> edu >> emory >> mathcs >> util >> [ concurrent overview ]	PREV CLASS  NEXT CLASS
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