DefaultPoolService.java
package org.apache.fulcrum.pool;
import java.util.HashMap;
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
import java.util.Map;
import org.apache.avalon.framework.activity.Disposable;
import org.apache.avalon.framework.activity.Initializable;
import org.apache.avalon.framework.configuration.Configurable;
import org.apache.avalon.framework.configuration.Configuration;
import org.apache.avalon.framework.logger.AbstractLogEnabled;
import org.apache.avalon.framework.service.ServiceManager;
import org.apache.avalon.framework.service.Serviceable;
import org.apache.fulcrum.factory.FactoryException;
import org.apache.fulcrum.factory.FactoryService;
/**
* The Pool Service extends the Factory Service by adding support for pooling
* instantiated objects. When a new instance is requested, the service first
* checks its pool if one is available. If the the pool is empty, a new instance
* will be requested from the FactoryService.
*
* For objects implementing the Recyclable interface, a recycle method will be
* called, when they taken from the pool, and a dispose method, when they are
* returned to the pool.
*
* @author <a href="mailto:ilkka.priha@simsoft.fi">Ilkka Priha</a>
* @author <a href="mailto:mcconnell@apache.org">Stephen McConnell</a>
* @version $Id$
*
* avalon.component name="pool" lifestyle="transient"
* avalon.service type="org.apache.fulcrum.pool.PoolService"
*/
public class DefaultPoolService extends AbstractLogEnabled
implements PoolService, Serviceable, Disposable, Initializable, Configurable {
/**
* The property specifying the pool capacity.
*/
public static final String POOL_CAPACITY = "capacity";
/**
* The default capacity of pools.
*/
private int poolCapacity = DEFAULT_POOL_CAPACITY;
/**
* The pool repository, one pool for each class.
*/
private HashMap<String, PoolBuffer> poolRepository = new HashMap<>();
private Map<String, Integer> capacityMap;
private FactoryService factoryService;
private ServiceManager manager;
/**
* Gets an instance of a named class either from the pool or by calling the
* Factory Service if the pool is empty.
*
* @param className the name of the class.
* @return the instance.
* @throws PoolException if recycling fails.
*/
public <T> T getInstance(String className) throws PoolException
{
try
{
T instance = pollInstance(className, null, null);
return instance == null ? getFactory().getInstance(className) : instance;
}
catch (FactoryException fe)
{
throw new PoolException(fe);
}
}
/**
* Gets an instance of a named class either from the pool or by calling the
* Factory Service if the pool is empty. The specified class loader will be
* passed to the Factory Service.
*
* @param className the name of the class.
* @param loader the class loader.
* @return the instance.
* @throws PoolException if recycling fails.
*/
public Object getInstance(String className, ClassLoader loader) throws PoolException
{
try
{
Object instance = pollInstance(className, null, null);
return instance == null ? getFactory().getInstance(className, loader) : instance;
}
catch (FactoryException fe)
{
throw new PoolException(fe);
}
}
/**
* Gets an instance of a named class either from the pool or by calling the
* Factory Service if the pool is empty. Parameters for its constructor are
* given as an array of objects, primitive types must be wrapped with a
* corresponding class.
*
* @param className the name of the class.
* @param params an array containing the parameters of the constructor.
* @param signature an array containing the signature of the constructor.
* @return the instance.
* @throws PoolException if recycling fails.
*/
public Object getInstance(String className, Object[] params, String[] signature) throws PoolException
{
try
{
Object instance = pollInstance(className, params, signature);
return instance == null ? getFactory().getInstance(className, params, signature) : instance;
}
catch (FactoryException fe)
{
throw new PoolException(fe);
}
}
/**
* Gets an instance of a named class either from the pool or by calling the
* Factory Service if the pool is empty. Parameters for its constructor are
* given as an array of objects, primitive types must be wrapped with a
* corresponding class. The specified class loader will be passed to the Factory
* Service.
*
* @param className the name of the class.
* @param loader the class loader.
* @param params an array containing the parameters of the constructor.
* @param signature an array containing the signature of the constructor.
* @return the instance.
* @throws PoolException if recycling fails.
*/
public Object getInstance(String className, ClassLoader loader, Object[] params, String[] signature)
throws PoolException
{
try
{
Object instance = pollInstance(className, params, signature);
return instance == null ? getFactory().getInstance(className, loader, params, signature) : instance;
}
catch (FactoryException fe)
{
throw new PoolException(fe);
}
}
/**
* Tests if specified class loaders are supported for a named class.
*
* @param className the name of the class.
* @return true if class loaders are supported, false otherwise.
* @throws FactoryException if test fails.
*/
public boolean isLoaderSupported(String className) throws FactoryException
{
return getFactory().isLoaderSupported(className);
}
/**
* Gets an instance of a specified class either from the pool or by instatiating
* from the class if the pool is empty.
*
* @param <T> type of the class
* @param clazz the class.
* @return the instance.
* @throws PoolException if recycling fails.
*/
@SuppressWarnings("unchecked")
public <T> T getInstance(Class<?> clazz) throws PoolException
{
try
{
T instance = pollInstance(clazz.getName(), null, null);
return instance == null ? (T) factoryService.getInstance(clazz) : instance;
}
catch (FactoryException fe)
{
throw new PoolException(fe);
}
}
/**
* Gets an instance of a specified class either from the pool or by instatiating
* from the class if the pool is empty.
*
* @param clazz the class.
* @param params an array containing the parameters of the constructor.
* @param signature an array containing the signature of the constructor.
* @return the instance.
* @throws PoolException if recycling fails.
*/
public <T> T getInstance(Class<?> clazz, Object params[], String signature[]) throws PoolException
{
try
{
T instance = pollInstance(clazz.getName(), params, signature);
// TODO There is a whacky .toString() on the clazz object,
// but otherwise it won't compile
return instance == null ? getFactory().getInstance(clazz.toString(), params, signature) : instance;
}
catch (FactoryException fe)
{
throw new PoolException(fe);
}
}
/**
* Puts a used object back to the pool. Objects implementing the Recyclable
* interface can provide a recycle method to be called when they are reused and
* a dispose method to be called when they are returned to the pool.
*
* @param instance the object instance to recycle.
* @return true if the instance was accepted.
*/
@SuppressWarnings("unchecked")
public boolean putInstance(Object instance)
{
if (instance != null)
{
HashMap<String, PoolBuffer> repository = poolRepository;
String className = instance.getClass().getName();
PoolBuffer pool = (PoolBuffer) repository.get(className);
if (pool == null)
{
pool = new PoolBuffer(getCapacity(className));
repository = (HashMap<String, PoolBuffer>) repository.clone();
repository.put(className, pool);
poolRepository = repository;
if (instance instanceof ArrayCtorRecyclable)
{
pool.setArrayCtorRecyclable(true);
}
}
return pool.offer(instance);
} else {
return false;
}
}
/**
* Gets the capacity of the pool for a named class.
*
* @param className the name of the class.
*/
public int getCapacity(String className)
{
PoolBuffer pool = (PoolBuffer) poolRepository.get(className);
if (pool == null)
{
/* Check class specific capacity. */
int capacity = poolCapacity;
if (capacityMap != null)
{
Integer cap = (Integer) capacityMap.get(className);
if (cap != null)
{
capacity = cap.intValue();
}
}
return capacity;
} else {
return pool.capacity();
}
}
/**
* Sets the capacity of the pool for a named class. Note that the pool will be
* cleared after the change.
*
* @param className the name of the class.
* @param capacity the new capacity.
*/
@SuppressWarnings("unchecked")
public void setCapacity(String className, int capacity)
{
HashMap<String, PoolBuffer> repository = poolRepository;
repository = repository != null ? (HashMap<String, PoolBuffer>) repository.clone()
: new HashMap<String, PoolBuffer>();
repository.put(className, new PoolBuffer(capacity));
poolRepository = repository;
}
/**
* Gets the current size of the pool for a named class.
*
* @param className the name of the class.
*/
public int getSize(String className)
{
PoolBuffer pool = (PoolBuffer) poolRepository.get(className);
return pool != null ? pool.size() : 0;
}
/**
* Clears instances of a named class from the pool.
*
* @param className the name of the class.
*/
@SuppressWarnings("unchecked")
public void clearPool(String className)
{
HashMap<String, PoolBuffer> repository = poolRepository;
if (repository.get(className) != null)
{
repository = (HashMap<String, PoolBuffer>) repository.clone();
repository.remove(className);
poolRepository = repository;
}
}
/**
* Clears all instances from the pool.
*/
public void clearPool()
{
poolRepository = new HashMap<String, PoolBuffer>();
}
/**
* Polls and recycles an object of the named class from the pool.
*
* @param className the name of the class.
* @param params an array containing the parameters of the constructor.
* @param signature an array containing the signature of the constructor.
* @return the object or null.
* @throws PoolException if recycling fails.
*/
private <T> T pollInstance(String className, Object[] params, String[] signature) throws PoolException
{
PoolBuffer pool = (PoolBuffer) poolRepository.get(className);
return pool != null ? pool.poll(params, signature, factoryService) : null;
}
/**
* Gets the factory service.
*
* @return the factory service.
*/
protected FactoryService getFactory()
{
return factoryService;
}
// ---------------- Avalon Lifecycle Methods ---------------------
/* (non-Javadoc)
* Avalon component lifecycle method
* @see org.apache.avalon.framework.configuration.Configurable#configure(org.apache.avalon.framework.configuration.Configuration)
*/
public void configure(Configuration conf)
{
final Configuration capacities = conf.getChild(POOL_CAPACITY, false);
if (capacities != null)
{
Configuration defaultConf = capacities.getChild("default");
int capacity = defaultConf.getValueAsInteger(DEFAULT_POOL_CAPACITY);
if (capacity <= 0)
{
throw new IllegalArgumentException("Capacity must be >0");
}
poolCapacity = capacity;
Configuration[] nameVal = capacities.getChildren();
for (int i = 0; i < nameVal.length; i++)
{
String key = nameVal[i].getName();
if (!"default".equals(key))
{
capacity = nameVal[i].getValueAsInteger(poolCapacity);
if (capacity < 0)
{
capacity = poolCapacity;
}
if (capacityMap == null)
{
capacityMap = new HashMap<String, Integer>();
}
capacityMap.put(key, capacity);
}
}
}
}
/**
* Avalon component lifecycle method
*
* {@link org.apache.fulcrum.factory.FactoryService}
*
* @param manager the service manager
*/
public void service(ServiceManager manager)
{
this.manager = manager;
}
/**
* Avalon component lifecycle method Initializes the service by loading default
* class loaders and customized object factories.
*
* @throws Exception if initialization fails.
*/
public void initialize() throws Exception
{
try
{
factoryService = (FactoryService) manager.lookup(FactoryService.ROLE);
}
catch (Exception e)
{
throw new Exception("DefaultPoolService.initialize: Failed to get a Factory object", e);
}
}
/**
* Avalon component lifecycle method
*/
public void dispose()
{
if (factoryService != null)
{
manager.release(factoryService);
}
factoryService = null;
manager = null;
}
}