com.gargoylesoftware.base.trace

Class BlockingCircularQueue

public class BlockingCircularQueue extends Object implements Serializable

Internal use only.

A circular queue with blocking semantics.

Version: $Revision: 1.7 $

Field Summary
Object	addLock_
int	back_
int	capacity_
int	front_
Object	getLock_
Object[]	queue_
static long	serialVersionUID
int	size_

Constructor Summary
	BlockingCircularQueue() Create the queue with a capacity of 20
	BlockingCircularQueue(int capacity) Create the queue with the specified capacity

Method Summary
boolean	add(Object object) Add an object to the queue.
protected void	assertNotNull(String fieldName, Object fieldValue) Verify that the specified value is not null.
void	clear() Remove all items from the queue
int	incrementPosition(int position) Utility method to increment the position and roll back to zero once we hit the end.
boolean	isEmpty() Return true if the collection is empty.
Object	next() Return the next item in the queue.
int	size() Return the number of objects currently in the collection.
String	toString() Return a string representation of this object.

Field Detail

addLock_

private final Object addLock_

back_

private int back_

capacity_

private final int capacity_

front_

private int front_

getLock_

private final Object getLock_

queue_

private final Object[] queue_

serialVersionUID

private static final long serialVersionUID

size_

private int size_

Constructor Detail

BlockingCircularQueue

public BlockingCircularQueue()

Create the queue with a capacity of 20

BlockingCircularQueue

public BlockingCircularQueue(int capacity)

Create the queue with the specified capacity

Parameters: capacity The size of the queue

Method Detail

add

public boolean add(Object object)

Add an object to the queue. If the collection is currently full then block until an object is removed.

Parameters: object The object to add.

Returns: true if the object was successfully added.

assertNotNull

protected final void assertNotNull(String fieldName, Object fieldValue)

Verify that the specified value is not null. If it is then throw an exception

Parameters: fieldName The name of the field to check fieldValue The value of the field to check

Throws: DetailedNullPointerException If fieldValue is null

clear

public void clear()

Remove all items from the queue

incrementPosition

private int incrementPosition(int position)

Utility method to increment the position and roll back to zero once we hit the end. Return the new position after the adjustment.

Parameters: position The position to increment

Returns: the new position

isEmpty

public boolean isEmpty()

Return true if the collection is empty.

Returns: true if the collection is empty.

public Object next()

Return the next item in the queue. The returned item is removed from the collection. If no objects are present then block until an object has been added.

Returns: The next item.

size

public int size()

Return the number of objects currently in the collection.

Returns: The object count.

toString

public String toString()

Return a string representation of this object.

Returns: a string representation of this object.