1 /* 2 * Copyright (c) 2015, 2017, Oracle and/or its affiliates. All rights reserved. 3 */ 4 /* 5 * Licensed to the Apache Software Foundation (ASF) under one or more 6 * contributor license agreements. See the NOTICE file distributed with 7 * this work for additional information regarding copyright ownership. 8 * The ASF licenses this file to You under the Apache License, Version 2.0 9 * (the "License"); you may not use this file except in compliance with 10 * the License. You may obtain a copy of the License at 11 * 12 * http://www.apache.org/licenses/LICENSE-2.0 13 * 14 * Unless required by applicable law or agreed to in writing, software 15 * distributed under the License is distributed on an "AS IS" BASIS, 16 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 17 * See the License for the specific language governing permissions and 18 * limitations under the License. 19 */ 20 /* 21 * $Id: CustomStringPool.java,v 1.2.4.1 2005/09/15 08:14:59 suresh_emailid Exp $ 22 */ 23 package com.sun.org.apache.xml.internal.dtm.ref; 24 25 import java.util.HashMap; 26 import java.util.Map; 27 28 /** 29 * CustomStringPool is an example of an application-provided data structure for a 30 * DTM implementation to hold symbol references, e.g. element names. It will 31 * follow the DTMStringPool interface and use two simple methods 32 * indexToString(int i) and stringToIndex(String s) to map between a set of 33 * string values and a set of integer index values. Therefore, an application 34 * may improve DTM processing speed by substituting the DTM symbol resolution 35 * tables with application specific quick symbol resolution tables. 36 * <p> 37 * %REVIEW% The only difference between this an DTMStringPool seems to be that 38 * it uses a java.lang.Hashtable full of Integers rather than implementing its 39 * own hashing. Joe deliberately avoided that approach when writing 40 * DTMStringPool, since it is both much more memory-hungry and probably slower 41 * -- especially in JDK 1.1.x, where Hashtable is synchronized. We need to 42 * either justify this implementation or discard it. 43 * 44 * <p> 45 * Status: In progress, under discussion. 46 * 47 * @LastModified: Oct 2017 48 */ 49 public class CustomStringPool extends DTMStringPool { 50 51 final Map<String, Integer> m_stringToInt = new HashMap<>(); 52 public static final int NULL = -1; 53 54 public CustomStringPool() { 55 super(); 56 } 57 58 public void removeAllElements() { 59 m_intToString.clear(); 60 if (m_stringToInt != null) { 61 m_stringToInt.clear(); 62 } 63 } 64 65 /** 66 * @return string whose value is uniquely identified by this integer index. 67 * @throws java.lang.IndexOutOfBoundsException if index doesn't map to 68 * a string. 69 */ 70 @Override 71 public String indexToString(int i) 72 throws IndexOutOfBoundsException { 73 return m_intToString.get(i); 74 } 75 76 /** 77 * @return integer index uniquely identifying the value of this string. 78 */ 79 @Override 80 public int stringToIndex(String s) { 81 if (s == null) { 82 return NULL; 83 } 84 Integer iobj = m_stringToInt.get(s); 85 if (iobj == null) { 86 m_intToString.add(s); 87 iobj = m_intToString.size(); 88 m_stringToInt.put(s, iobj); 89 } 90 return iobj; 91 } 92 }