| /* |
| * The Apache Software License, Version 1.1 |
| * |
| * |
| * Copyright (c) 1999 The Apache Software Foundation. All rights |
| * reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * |
| * 3. The end-user documentation included with the redistribution, |
| * if any, must include the following acknowledgment: |
| * "This product includes software developed by the |
| * Apache Software Foundation (http://www.apache.org/)." |
| * Alternately, this acknowledgment may appear in the software itself, |
| * if and wherever such third-party acknowledgments normally appear. |
| * |
| * 4. The names "Xalan" and "Apache Software Foundation" must |
| * not be used to endorse or promote products derived from this |
| * software without prior written permission. For written |
| * permission, please contact apache@apache.org. |
| * |
| * 5. Products derived from this software may not be called "Apache", |
| * nor may "Apache" appear in their name, without prior written |
| * permission of the Apache Software Foundation. |
| * |
| * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED |
| * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
| * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR |
| * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF |
| * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
| * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
| * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT |
| * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| * SUCH DAMAGE. |
| * ==================================================================== |
| * |
| * This software consists of voluntary contributions made by many |
| * individuals on behalf of the Apache Software Foundation and was |
| * originally based on software copyright (c) 1999, Lotus |
| * Development Corporation., http://www.lotus.com. For more |
| * information on the Apache Software Foundation, please see |
| * <http://www.apache.org/>. |
| */ |
| package org.apache.xml.utils; |
| |
| import java.util.*; |
| |
| import org.apache.xalan.res.XSLTErrorResources; |
| import org.apache.xalan.res.XSLMessages; |
| |
| |
| /** |
| * <meta name="usage" content="internal"/> |
| * Pool of object of a given type to pick from to help memory usage |
| */ |
| public class ObjectPool implements java.io.Serializable |
| { |
| |
| /** Type of objects in this pool. |
| * @serial */ |
| private final Class objectType; |
| |
| /** Vector of given objects this points to. |
| * @serial */ |
| private final Vector freeStack; |
| |
| /** |
| * Constructor ObjectPool |
| * |
| * @param type Type of objects for this pool |
| */ |
| public ObjectPool(Class type) |
| { |
| objectType = type; |
| freeStack = new Vector(); |
| } |
| |
| /** |
| * Constructor ObjectPool |
| * |
| * @param className Fully qualified name of the type of objects for this pool. |
| */ |
| public ObjectPool(String className) |
| { |
| try |
| { |
| objectType = Class.forName(className); |
| } |
| catch(ClassNotFoundException cnfe) |
| { |
| throw new WrappedRuntimeException(cnfe); |
| } |
| freeStack = new Vector(); |
| } |
| |
| |
| /** |
| * Constructor ObjectPool |
| * |
| * |
| * @param type Type of objects for this pool |
| * @param size Size of vector to allocate |
| */ |
| public ObjectPool(Class type, int size) |
| { |
| objectType = type; |
| freeStack = new Vector(size); |
| } |
| |
| /** |
| * Constructor ObjectPool |
| * |
| */ |
| public ObjectPool() |
| { |
| objectType = null; |
| freeStack = new Vector(); |
| } |
| |
| /** |
| * Get an instance of the given object in this pool if available |
| * |
| * |
| * @return an instance of the given object if available or null |
| */ |
| public synchronized Object getInstanceIfFree() |
| { |
| |
| // Check if the pool is empty. |
| if (!freeStack.isEmpty()) |
| { |
| |
| // Remove object from end of free pool. |
| Object result = freeStack.lastElement(); |
| |
| freeStack.setSize(freeStack.size() - 1); |
| |
| return result; |
| } |
| |
| return null; |
| } |
| |
| /** |
| * Get an instance of the given object in this pool |
| * |
| * |
| * @return An instance of the given object |
| */ |
| public synchronized Object getInstance() |
| { |
| |
| // Check if the pool is empty. |
| if (freeStack.isEmpty()) |
| { |
| |
| // Create a new object if so. |
| try |
| { |
| return objectType.newInstance(); |
| } |
| catch (InstantiationException ex){} |
| catch (IllegalAccessException ex){} |
| |
| // Throw unchecked exception for error in pool configuration. |
| throw new RuntimeException(XSLMessages.createMessage(XSLTErrorResources.ER_EXCEPTION_CREATING_POOL, null)); //"exception creating new instance for pool"); |
| } |
| else |
| { |
| |
| // Remove object from end of free pool. |
| Object result = freeStack.lastElement(); |
| |
| freeStack.setSize(freeStack.size() - 1); |
| |
| return result; |
| } |
| } |
| |
| /** |
| * Add an instance of the given object to the pool |
| * |
| * |
| * @param obj Object to add. |
| */ |
| public synchronized void freeInstance(Object obj) |
| { |
| |
| // Make sure the object is of the correct type. |
| // Remove safety. -sb |
| // if (objectType.isInstance(obj)) |
| // { |
| freeStack.addElement(obj); |
| // } |
| // else |
| // { |
| // throw new IllegalArgumentException("argument type invalid for pool"); |
| // } |
| } |
| } |