19f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson/* 29f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Licensed to the Apache Software Foundation (ASF) under one 39f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * or more contributor license agreements. See the NOTICE file 49f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * distributed with this work for additional information 59f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * regarding copyright ownership. The ASF licenses this file 69f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * to you under the Apache License, Version 2.0 (the "License"); 79f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * you may not use this file except in compliance with the License. 89f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * You may obtain a copy of the License at 99f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * 109f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * http://www.apache.org/licenses/LICENSE-2.0 119f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * 129f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Unless required by applicable law or agreed to in writing, software 139f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * distributed under the License is distributed on an "AS IS" BASIS, 149f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 159f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * See the License for the specific language governing permissions and 169f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * limitations under the License. 179f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 189f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson/* 199f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * $Id: IteratorPool.java 475981 2006-11-16 23:35:53Z minchau $ 209f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 219f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilsonpackage org.apache.xpath.axes; 229f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 239f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilsonimport java.util.ArrayList; 249f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 259f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilsonimport org.apache.xml.dtm.DTMIterator; 269f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilsonimport org.apache.xml.utils.WrappedRuntimeException; 279f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 289f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson/** 299f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Pool of object of a given type to pick from to help memory usage 309f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @xsl.usage internal 319f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 329f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilsonpublic final class IteratorPool implements java.io.Serializable 339f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson{ 349f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson static final long serialVersionUID = -460927331149566998L; 359f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 369f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson /** 379f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Type of objects in this pool. 389f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 399f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson private final DTMIterator m_orig; 409f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 419f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson /** 429f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Stack of given objects this points to. 439f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 449f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson private final ArrayList m_freeStack; 459f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 469f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson /** 479f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Constructor IteratorPool 489f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * 499f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @param original The original iterator from which all others will be cloned. 509f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 519f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson public IteratorPool(DTMIterator original) 529f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson { 539f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson m_orig = original; 549f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson m_freeStack = new ArrayList(); 559f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson } 569f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 579f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson /** 589f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Get an instance of the given object in this pool 599f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * 609f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @return An instance of the given object 619f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 629f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson public synchronized DTMIterator getInstanceOrThrow() 639f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson throws CloneNotSupportedException 649f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson { 659f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson // Check if the pool is empty. 669f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson if (m_freeStack.isEmpty()) 679f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson { 689f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 699f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson // Create a new object if so. 709f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson return (DTMIterator)m_orig.clone(); 719f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson } 729f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson else 739f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson { 749f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson // Remove object from end of free pool. 759f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson DTMIterator result = (DTMIterator)m_freeStack.remove(m_freeStack.size() - 1); 769f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson return result; 779f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson } 789f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson } 799f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 809f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson /** 819f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Get an instance of the given object in this pool 829f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * 839f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @return An instance of the given object 849f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 859f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson public synchronized DTMIterator getInstance() 869f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson { 879f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson // Check if the pool is empty. 889f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson if (m_freeStack.isEmpty()) 899f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson { 909f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 919f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson // Create a new object if so. 929f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson try 939f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson { 949f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson return (DTMIterator)m_orig.clone(); 959f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson } 969f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson catch (Exception ex) 979f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson { 989f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson throw new WrappedRuntimeException(ex); 999f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson } 1009f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson } 1019f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson else 1029f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson { 1039f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson // Remove object from end of free pool. 1049f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson DTMIterator result = (DTMIterator)m_freeStack.remove(m_freeStack.size() - 1); 1059f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson return result; 1069f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson } 1079f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson } 1089f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 1099f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson /** 1109f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Add an instance of the given object to the pool 1119f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * 1129f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * 1139f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @param obj Object to add. 1149f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 1159f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson public synchronized void freeInstance(DTMIterator obj) 1169f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson { 1179f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson m_freeStack.add(obj); 1189f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson } 1199f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson} 120