com.eibus.util

Class Queue

java.lang.Object

com.eibus.util.Queue

public class Queue
extends java.lang.Object

This class contains Blocking Queue functionality. If the queue is empty, the method get() will block until another thread has put an object in the queue. Similarly, the method put() blocks if the queue is full. However, the put() method will not block if the queue has no maximum size. To create a new queue, the maximum size must be specified. This is an integer, and if it has a value of zero or less than zero, it is assumed that the queue has no maximum size. The Queue class is thread safe. This means that your methods for calling the get() and put() method need not synchronize on the queue object.

Constructor Summary

Constructors

Constructor and Description
Queue(int maximumSize) Creates a new queue of the specified size.

Method Summary

Methods

Modifier and Type	Method and Description
java.lang.Object	get() Gets an object from queue.
java.lang.Object	get(long timeout) Gets an object from queue, within a given timeout period.
int	getMaxSize() Returns the maximum queue size
java.lang.Object	nonBlockingGet() This method returns either the front object from the queue, or null if the queue is empty.
void	nonBlockingPut(java.lang.Object object) Put a object in the queue, non blocking, the queue could grow over it's max size.
protected void	notifyGetWait(int duration) Extension point for any sub-classes that want to be informed about incured during 'get' operations.
protected void	notifyPutWait(int duration) Extension point for any sub-classes that want to be informed about incured during 'put' operations.
void	put(java.lang.Object object) Put an object into queue.
int	size() Returns the number of items currently in the queue.

Methods inherited from class java.lang.Object

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

Constructor Detail

Queue

public Queue(int maximumSize)

Creates a new queue of the specified size. If the value for maximum size is less than or equal to zero, the queue has no maximum size (i.e., the put() method is not blocking).

Parameters:

maximumSize - The maximum size for the queue; if this is less than or equal to zero, the queue does not have a maximum size.

Method Detail

nonBlockingGet

public java.lang.Object nonBlockingGet()

This method returns either the front object from the queue, or null if the queue is empty. It will not block.

Returns:

The front object of the queue, or null if the queue is empty.

nonBlockingPut

public void nonBlockingPut(java.lang.Object object)

Put a object in the queue, non blocking, the queue could grow over it's max size.

Parameters:

object -

get

public java.lang.Object get()

Gets an object from queue. This method blocks if the queue is empty.

Returns:

The object that was in the front of the queue.

get

public java.lang.Object get(long timeout)

Gets an object from queue, within a given timeout period. This method blocks till the timeout is expired or an object is found in the queue.

Parameters:

timeout - the maximum time to wait in milliseconds.

Returns:

The object that was in the front of the queue or null when the timeout expired or the wait was interrupted.

put

public void put(java.lang.Object object)

Put an object into queue. This method blocks if a maximum size for the queue has been specified and the queue is full. Otherwise, it will return immediately.

Parameters:

object - The object to put in the queue.

size

public int size()

Returns the number of items currently in the queue.

Returns:

The current number of items in the queue.

getMaxSize

public int getMaxSize()

Returns the maximum queue size

Returns:

the maximum queue size

notifyGetWait

protected void notifyGetWait(int duration)

Extension point for any sub-classes that want to be informed about incured during 'get' operations.

Parameters:

duration - Duration of the wait period before 'get' finds an item

notifyPutWait

protected void notifyPutWait(int duration)

Extension point for any sub-classes that want to be informed about incured during 'put' operations.

Parameters:

duration - Duration of the wait period before 'put' finds a free spot