org.apache.commons.pool2.proxy

Class ProxiedObjectPool<T>

java.lang.Object

org.apache.commons.pool2.proxy.ProxiedObjectPool<T>

Type Parameters:

T - type of the pooled object

All Implemented Interfaces:

ObjectPool<T>

public class ProxiedObjectPool<T>
extends java.lang.Object
implements ObjectPool<T>

Create a new object pool where the pooled objects are wrapped in proxies allowing better control of pooled objects and in particular the prevention of the continued use of an object by a client after that client returns the object to the pool.

Since:

2.0

Field Summary

Fields

Modifier and Type	Field and Description
private ObjectPool<T>	pool
private ProxySource<T>	proxySource

Constructor Summary

Constructors

Constructor and Description
ProxiedObjectPool(ObjectPool<T> pool, ProxySource<T> proxySource) Create a new proxied object pool.

Method Summary

Modifier and Type	Method and Description
void	addObject() Create an object using the factory or other implementation dependent mechanism, passivate it, and then place it in the idle object pool.
T	borrowObject() Obtains an instance from this pool.
void	clear() Clears any objects sitting idle in the pool, releasing any associated resources (optional operation).
void	close() Close this pool, and free any resources associated with it.
int	getNumActive() Return the number of instances currently borrowed from this pool.
int	getNumIdle() Return the number of instances currently idle in this pool.
void	invalidateObject(T proxy) Invalidates an object from the pool.
void	returnObject(T proxy) Return an instance to the pool.

Methods inherited from class java.lang.Object

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

Field Detail

pool

private final ObjectPool<T> pool

proxySource

private final ProxySource<T> proxySource

Constructor Detail

ProxiedObjectPool

public ProxiedObjectPool(ObjectPool<T> pool,
                         ProxySource<T> proxySource)

Create a new proxied object pool.

Parameters:

pool - The object pool to wrap

proxySource - The source of the proxy objects

Method Detail

borrowObject

public T borrowObject()
               throws java.lang.Exception,
                      java.util.NoSuchElementException,
                      java.lang.IllegalStateException

Description copied from interface: ObjectPool

Obtains an instance from this pool.

Instances returned from this method will have been either newly created with PooledObjectFactory.makeObject() or will be a previously idle object and have been activated with PooledObjectFactory.activateObject(org.apache.commons.pool2.PooledObject<T>) and then validated with PooledObjectFactory.validateObject(org.apache.commons.pool2.PooledObject<T>).

By contract, clients must return the borrowed instance using ObjectPool.returnObject(T), ObjectPool.invalidateObject(T), or a related method as defined in an implementation or sub-interface.

The behaviour of this method when the pool has been exhausted is not strictly specified (although it may be specified by implementations).

Specified by:

borrowObject in interface ObjectPool<T>

Returns:

an instance from this pool.

Throws:

java.lang.IllegalStateException - after close has been called on this pool.

java.lang.Exception - when PooledObjectFactory.makeObject() throws an exception.

java.util.NoSuchElementException - when the pool is exhausted and cannot or will not return another instance.

returnObject

public void returnObject(T proxy)
                  throws java.lang.Exception

Description copied from interface: ObjectPool

Return an instance to the pool. By contract, obj must have been obtained using ObjectPool.borrowObject() or a related method as defined in an implementation or sub-interface.

Specified by:

returnObject in interface ObjectPool<T>

Parameters:

proxy - a borrowed instance to be returned.

Throws:

java.lang.IllegalStateException - if an attempt is made to return an object to the pool that is in any state other than allocated (i.e. borrowed). Attempting to return an object more than once or attempting to return an object that was never borrowed from the pool will trigger this exception.

java.lang.Exception - if an instance cannot be returned to the pool

invalidateObject

public void invalidateObject(T proxy)
                      throws java.lang.Exception

Description copied from interface: ObjectPool

Invalidates an object from the pool.

By contract, obj must have been obtained using ObjectPool.borrowObject() or a related method as defined in an implementation or sub-interface.

This method should be used when an object that has been borrowed is determined (due to an exception or other problem) to be invalid.

Specified by:

invalidateObject in interface ObjectPool<T>

Parameters:

proxy - a borrowed instance to be disposed.

Throws:

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

addObject

public void addObject()
               throws java.lang.Exception,
                      java.lang.IllegalStateException,
                      java.lang.UnsupportedOperationException

Description copied from interface: ObjectPool

Create an object using the factory or other implementation dependent mechanism, passivate it, and then place it in the idle object pool. addObject is useful for "pre-loading" a pool with idle objects. (Optional operation).

Specified by:

addObject in interface ObjectPool<T>

Throws:

java.lang.Exception - when PooledObjectFactory.makeObject() fails.

java.lang.IllegalStateException - after ObjectPool.close() has been called on this pool.

java.lang.UnsupportedOperationException - when this pool cannot add new idle objects.

getNumIdle

public int getNumIdle()

Description copied from interface: ObjectPool

Return the number of instances currently idle in this pool. This may be considered an approximation of the number of objects that can be borrowed without creating any new instances. Returns a negative value if this information is not available.

Specified by:

getNumIdle in interface ObjectPool<T>

Returns:

the number of instances currently idle in this pool.

getNumActive

public int getNumActive()

Description copied from interface: ObjectPool

Return the number of instances currently borrowed from this pool. Returns a negative value if this information is not available.

Specified by:

getNumActive in interface ObjectPool<T>

Returns:

the number of instances currently borrowed from this pool.

clear

public void clear()
           throws java.lang.Exception,
                  java.lang.UnsupportedOperationException

Description copied from interface: ObjectPool

Clears any objects sitting idle in the pool, releasing any associated resources (optional operation). Idle objects cleared must be PooledObjectFactory.destroyObject(PooledObject).

Specified by:

clear in interface ObjectPool<T>

Throws:

java.lang.UnsupportedOperationException - if this implementation does not support the operation

java.lang.Exception - if the pool cannot be cleared

close

public void close()

Description copied from interface: ObjectPool

Close this pool, and free any resources associated with it.

Calling ObjectPool.addObject() or ObjectPool.borrowObject() after invoking this method on a pool will cause them to throw an IllegalStateException.

Implementations should silently fail if not all resources can be freed.

Specified by:

close in interface ObjectPool<T>