1 /* ObjectId.java -- Simple object identification mechanism for XML encoding. 2 Copyright (C) 2005 Free Software Foundation, Inc. 3 4 This file is part of GNU Classpath. 5 6 GNU Classpath is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 2, or (at your option) 9 any later version. 10 11 GNU Classpath is distributed in the hope that it will be useful, but 12 WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 General Public License for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with GNU Classpath; see the file COPYING. If not, write to the 18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 19 02110-1301 USA. 20 21 Linking this library statically or dynamically with other modules is 22 making a combined work based on this library. Thus, the terms and 23 conditions of the GNU General Public License cover the whole 24 combination. 25 26 As a special exception, the copyright holders of this library give you 27 permission to link this library with independent modules to produce an 28 executable, regardless of the license terms of these independent 29 modules, and to copy and distribute the resulting executable under 30 terms of your choice, provided that you also meet, for each linked 31 independent module, the terms and conditions of the license of that 32 module. An independent module is a module which is not derived from 33 or based on this library. If you modify this library, you may extend 34 this exception to your version of the library, but you are not 35 obligated to do so. If you do not wish to do so, delete this 36 exception statement from your version. */ 37 38 39 package gnu.java.beans.encoder; 40 41 import java.util.HashMap; 42 43 /** 44 * <p> 45 * ObjectId provides an object identification mechanism which gives each object 46 * a name in the form <code><class><Nameindex></code>. 47 * </p> 48 * 49 * <p> 50 * Each id can be in an unused state which means that only one instance of the 51 * object is in use and a special id is not needed. Certain {@link 52 * gnu.java.beans.encoder.elements.Element} subclasses use this feature to find 53 * out whether they write the "id" attribute or not. 54 * </p> 55 * <p> 56 * An <code>ObjectId</code> instance is typically given to multiple objects. 57 * The second user should then invoke the {@link #init} method to generate the 58 * identification string and bring the id in the 'used' state. 59 * </p> 60 * 61 * @author Robert Schuster (robertschuster@fsfe.org) 62 */ 63 public class ObjectId 64 { 65 /** 66 * Stores the index an object of a specific type should be given. 67 */ 68 private static HashMap nameIndices = new HashMap(); 69 70 private String id; 71 72 private Class klass; 73 ObjectId(Class klass)74 ObjectId(Class klass) 75 { 76 this.klass = klass; 77 } 78 isUnused()79 public boolean isUnused() 80 { 81 return id == null; 82 } 83 toString()84 public String toString() 85 { 86 return (id != null) ? id : "<unused id>"; 87 } 88 89 /** 90 * <p> 91 * Generates a simple Id by concatenating a class name with a self-increasing 92 * number. 93 * </p> 94 */ init()95 public void init() 96 { 97 assert (klass != null); 98 99 if (id != null) 100 return; 101 102 Integer count = (Integer) nameIndices.get(klass); 103 if (count == null) 104 { 105 count = Integer.valueOf(0); 106 } 107 108 if (klass.isArray()) 109 { 110 Class ct = klass.getComponentType(); 111 if (ct == Boolean.TYPE) 112 id = "booleanArray" + count.intValue(); 113 else if (ct == Byte.TYPE) 114 id = "byteArray" + count.intValue(); 115 else if (ct == Short.TYPE) 116 id = "shortArray" + count.intValue(); 117 else if (ct == Integer.TYPE) 118 id = "intArray" + count.intValue(); 119 else if (ct == Long.TYPE) 120 id = "longArray" + count.intValue(); 121 else if (ct == Float.TYPE) 122 id = "floatArray" + count.intValue(); 123 else if (ct == Double.TYPE) 124 id = "doubleArray" + count.intValue(); 125 } 126 else 127 id = klass.getName() + count.intValue(); 128 129 nameIndices.put(klass, Integer.valueOf(count.intValue() + 1)); 130 } 131 132 } 133