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org.apache.excalibur.mpool
Class VariableSizePool

java.lang.Object
  org.apache.excalibur.mpool.VariableSizePool

All Implemented Interfaces:

Disposable, ManagablePool, Pool

public final class VariableSizePool

extends java.lang.Object

implements Pool, Disposable, ManagablePool

This is an Pool that caches Poolable objects for reuse. Please note that this pool offers no resource limiting whatsoever.

Since:

4.1

Version:

CVS $Revision: 1.4 $ $Date: 2004/02/28 11:47:34 $

Author:

Avalon Development Team

Constructor Summary

VariableSizePool(ObjectFactory factory, int size)
Constructor for an unmanaged pool

VariableSizePool(ObjectFactory factory, int size, long key)
Constructor for a managed pool

Method Summary

java.lang.Object	acquire() Acquire an instance of the pooled object.
void	dispose() The dispose operation is called at the end of a components lifecycle.
void	grow(int byNum, long key) Grow by the specified amount.
java.lang.Object	newInstance() Create a new instance of the object being pooled.
void	release(java.lang.Object pooledObject) Release the instance of the pooled object.
void	shrink(int byNum, long key) Shrink the pool by the specified amount.
int	size(long key) Determine the pool's current size.

Methods inherited from class java.lang.Object

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

Constructor Detail

VariableSizePool

public VariableSizePool(ObjectFactory factory,
                        int size)
                 throws java.lang.Exception

Constructor for an unmanaged pool

VariableSizePool

public VariableSizePool(ObjectFactory factory,
                        int size,
                        long key)
                 throws java.lang.Exception

Constructor for a managed pool

Method Detail

acquire

public java.lang.Object acquire()
                         throws java.lang.Exception

Description copied from interface: Pool

Acquire an instance of the pooled object.

Specified by:

acquire in interface Pool

Returns:

the pooled Object instance

Throws:

java.lang.Exception - if the Pool is not able to return an object.

release

public void release(java.lang.Object pooledObject)

Description copied from interface: Pool

Release the instance of the pooled object.

Specified by:

release in interface Pool

Parameters:

pooledObject - The pooled object to release to the pool.

newInstance

public java.lang.Object newInstance()
                             throws java.lang.Exception

Description copied from interface: Pool

Create a new instance of the object being pooled.

Specified by:

newInstance in interface Pool

Returns:

the pooled Object instance

Throws:

java.lang.Exception - if the instance cannot be created

dispose

public void dispose()

Description copied from interface: Disposable

The dispose operation is called at the end of a components lifecycle. This method will be called after Startable.stop() method (if implemented by component). Components use this method to release and destroy any resources that the Component owns.

Specified by:

dispose in interface Disposable

shrink

public void shrink(int byNum,
                   long key)
            throws java.lang.IllegalAccessException

Description copied from interface: ManagablePool

Shrink the pool by the specified amount. The pool should trust the Controller, but be smart enough not to achieve a negative pool size. In other words, you should clip the shrink amount so that the pool does not go below 0.

Specified by:

shrink in interface ManagablePool

Parameters:

byNum - an integer amount to decrease the pool size by.

key - an integer number supplied by the PoolManager to validate that the method is called legitimately

Throws:

java.lang.IllegalAccessException - if the key does not match the controller's key.

grow

public void grow(int byNum,
                 long key)
          throws java.lang.IllegalAccessException

Description copied from interface: ManagablePool

Grow by the specified amount. The pool should trust the Controller for the Grow size.

Specified by:

grow in interface ManagablePool

Parameters:

byNum - an integer amount to increase the pool size by.

key - an integer number supplied by the PoolManager to validate that the method is called legitimately

Throws:

java.lang.IllegalAccessException - if the key does not match the controller's key.

size

public int size(long key)
         throws java.lang.IllegalAccessException

Description copied from interface: ManagablePool

Determine the pool's current size. The size is defined as the number of Poolable objects in reserve.

Specified by:

size in interface ManagablePool

Parameters:

key - an integer number supplied by the PoolManager to validate that the method is called legitimately

Returns:

size of pool's reserve.

Throws:

java.lang.IllegalAccessException - if the key does not match the controller's key.