1 /*
2 * Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25 package java.beans;
26
27 import java.util.HashMap;
28 import java.util.IdentityHashMap;
29 import java.util.Map;
30
31 import static java.util.Locale.ENGLISH;
32
33 /**
34 * A utility class which generates unique names for object instances.
35 * The name will be a concatenation of the unqualified class name
36 * and an instance number.
37 * <p>
38 * For example, if the first object instance javax.swing.JButton
39 * is passed into <code>instanceName</code> then the returned
40 * string identifier will be "JButton0".
41 *
42 * @author Philip Milne
43 */
44 class NameGenerator {
45
46 private Map<Object, String> valueToName;
47 private Map<String, Integer> nameToCount;
48
49 public NameGenerator() {
50 valueToName = new IdentityHashMap<>();
51 nameToCount = new HashMap<>();
52 }
53
54 /**
55 * Clears the name cache. Should be called to near the end of
56 * the encoding cycle.
57 */
58 public void clear() {
59 valueToName.clear();
60 nameToCount.clear();
61 }
62
63 /**
64 * Returns the root name of the class.
65 */
66 @SuppressWarnings("rawtypes")
67 public static String unqualifiedClassName(Class type) {
68 if (type.isArray()) {
69 return unqualifiedClassName(type.getComponentType())+"Array";
70 }
71 String name = type.getName();
72 return name.substring(name.lastIndexOf('.')+1);
73 }
74
75 /**
76 * Returns a String which capitalizes the first letter of the string.
77 */
78 public static String capitalize(String name) {
79 if (name == null || name.length() == 0) {
80 return name;
81 }
82 return name.substring(0, 1).toUpperCase(ENGLISH) + name.substring(1);
83 }
84
85 /**
86 * Returns a unique string which identifies the object instance.
87 * Invocations are cached so that if an object has been previously
88 * passed into this method then the same identifier is returned.
89 *
90 * @param instance object used to generate string
91 * @return a unique string representing the object
92 */
93 public String instanceName(Object instance) {
94 if (instance == null) {
95 return "null";
96 }
97 if (instance instanceof Class) {
98 return unqualifiedClassName((Class)instance);
99 }
100 else {
101 String result = valueToName.get(instance);
102 if (result != null) {
103 return result;
104 }
105 Class<?> type = instance.getClass();
106 String className = unqualifiedClassName(type);
107
108 Integer size = nameToCount.get(className);
109 int instanceNumber = (size == null) ? 0 : (size).intValue() + 1;
110 nameToCount.put(className, instanceNumber);
111
112 result = className + instanceNumber;
113 valueToName.put(instance, result);
114 return result;
115 }
116 }
117 }