/*
 * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
 */
/*
 * 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
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package com.sun.org.apache.xml.internal.utils;

import com.sun.org.apache.xalan.internal.utils.ObjectFactory;
import com.sun.org.apache.xml.internal.res.XMLErrorResources;
import com.sun.org.apache.xml.internal.res.XMLMessages;
import java.lang.reflect.InvocationTargetException;
import java.util.ArrayList;
import java.util.List;


Pool of object of a given type to pick from to help memory usage
@xsl.usageinternal
@LastModified: Oct 2017
/** * Pool of object of a given type to pick from to help memory usage * @xsl.usage internal * @LastModified: Oct 2017 */
public class ObjectPool implements java.io.Serializable { static final long serialVersionUID = -8519013691660936643L;
Type of objects in this pool. @serial
/** Type of objects in this pool. * @serial */
private final Class<?> objectType;
Stack of given objects this points to. @serial
/** Stack of given objects this points to. * @serial */
private final List<Object> freeStack;
Constructor ObjectPool
Params:
  • type – Type of objects for this pool
/** * Constructor ObjectPool * * @param type Type of objects for this pool */
public ObjectPool(Class<?> type) { objectType = type; freeStack = new ArrayList<>(); }
Constructor ObjectPool
Params:
  • className – Fully qualified name of the type of objects for this pool.
/** * Constructor ObjectPool * * @param className Fully qualified name of the type of objects for this pool. */
public ObjectPool(String className) { try { objectType = ObjectFactory.findProviderClass(className, true); } catch(ClassNotFoundException cnfe) { throw new WrappedRuntimeException(cnfe); } freeStack = new ArrayList<>(); }
Constructor ObjectPool
Params:
  • type – Type of objects for this pool
  • size – Size of vector to allocate
/** * 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 ArrayList<>(size); }
Constructor ObjectPool
/** * Constructor ObjectPool * */
public ObjectPool() { objectType = null; freeStack = new ArrayList<>(); }
Get an instance of the given object in this pool if available
Returns:an instance of the given object if available or null
/** * 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.remove(freeStack.size() - 1); return result; } return null; }
Get an instance of the given object in this pool
Returns:An instance of the given object
/** * 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.getConstructor().newInstance(); } catch (InstantiationException | IllegalAccessException | SecurityException | IllegalArgumentException | InvocationTargetException | NoSuchMethodException ex){} // Throw unchecked exception for error in pool configuration. throw new RuntimeException(XMLMessages.createXMLMessage( XMLErrorResources.ER_EXCEPTION_CREATING_POOL, null)); } else { // Remove object from end of free pool. Object result = freeStack.remove(freeStack.size() - 1); return result; } }
Add an instance of the given object to the pool
Params:
  • obj – Object to add.
/** * 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.add(obj); // } // else // { // throw new IllegalArgumentException("argument type invalid for pool"); // } } }