1 /*
2 * The Apache Software License, Version 1.1
3 *
4 * Copyright (c) 2002 The Apache Software Foundation. All rights
5 * reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 *
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 *
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in
16 * the documentation and/or other materials provided with the
17 * distribution.
18 *
19 * 3. The end-user documentation included with the redistribution,
20 * if any, must include the following acknowledgment:
21 * "This product includes software developed by the
22 * Apache Software Foundation (http://www.apache.org/)."
23 * Alternately, this acknowledgment may appear in the software itself,
24 * if and wherever such third-party acknowledgments normally appear.
25 *
26 * 4. The names "Apache" and "Apache Software Foundation" must
27 * not be used to endorse or promote products derived from this
28 * software without prior written permission. For written
29 * permission, please contact apache@apache.org.
30 *
31 * 5. Products derived from this software may not be called "Apache",
32 * nor may "Apache" appear in their name, without prior written
33 * permission of the Apache Software Foundation.
34 *
35 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
36 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
37 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
38 * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
39 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
40 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
41 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
42 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
43 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
44 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
45 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
46 * SUCH DAMAGE.
47 * ====================================================================
48 *
49 * This software consists of voluntary contributions made by many
50 * individuals on behalf of the Apache Software Foundation. For more
51 * information on the Apache Software Foundation, please see
52 * <http://www.apache.org/>;.
53 */
54 package net.sf.cglib.util;
55
56 import java.util.*;
57 import net.sf.cglib.core.*;
58 import org.objectweb.asm.ClassVisitor;
59 import org.objectweb.asm.Label;
60 import org.objectweb.asm.Type;
61
62 /***
63 * This class implements a simple String->int mapping for a fixed set of keys.
64 */
65 abstract public class StringSwitcher {
66 private static final Type STRING_SWITCHER =
67 TypeUtils.parseType("net.sf.cglib.util.StringSwitcher");
68 private static final Signature INT_VALUE =
69 TypeUtils.parseSignature("int intValue(String)");
70 private static final StringSwitcherKey KEY_FACTORY =
71 (StringSwitcherKey)KeyFactory.create(StringSwitcherKey.class);
72
73 interface StringSwitcherKey {
74 public Object newInstance(String[] strings, int[] ints, boolean fixedInput);
75 }
76
77 /***
78 * Helper method to create a StringSwitcher.
79 * For finer control over the generated instance, use a new instance of StringSwitcher.Generator
80 * instead of this static method.
81 * @param strings the array of String keys; must be the same length as the value array
82 * @param ints the array of integer results; must be the same length as the key array
83 * @param fixedInput if false, an unknown key will be returned from {@link #intValue} as <code>-1</code>; if true,
84 * the result will be undefined, and the resulting code will be faster
85 */
86 public static StringSwitcher create(String[] strings, int[] ints, boolean fixedInput) {
87 Generator gen = new Generator();
88 gen.setStrings(strings);
89 gen.setInts(ints);
90 gen.setFixedInput(fixedInput);
91 return gen.create();
92 }
93
94 protected StringSwitcher() {
95 }
96
97 /***
98 * Return the integer associated with the given key.
99 * @param s the key
100 * @return the associated integer value, or <code>-1</code> if the key is unknown (unless
101 * <code>fixedInput</code> was specified when this <code>StringSwitcher</code> was created,
102 * in which case the return value for an unknown key is undefined)
103 */
104 abstract public int intValue(String s);
105
106 public static class Generator extends AbstractClassGenerator {
107 private static final Source SOURCE = new Source(StringSwitcher.class.getName());
108
109 private String[] strings;
110 private int[] ints;
111 private boolean fixedInput;
112
113 public Generator() {
114 super(SOURCE);
115 }
116
117 /***
118 * Set the array of recognized Strings.
119 * @param strings the array of String keys; must be the same length as the value array
120 * @see #setInts
121 */
122 public void setStrings(String[] strings) {
123 this.strings = strings;
124 }
125
126 /***
127 * Set the array of integer results.
128 * @param ints the array of integer results; must be the same length as the key array
129 * @see #setStrings
130 */
131 public void setInts(int[] ints) {
132 this.ints = ints;
133 }
134
135 /***
136 * Configure how unknown String keys will be handled.
137 * @param fixedInput if false, an unknown key will be returned from {@link #intValue} as <code>-1</code>; if true,
138 * the result will be undefined, and the resulting code will be faster
139 */
140 public void setFixedInput(boolean fixedInput) {
141 this.fixedInput = fixedInput;
142 }
143
144 protected ClassLoader getDefaultClassLoader() {
145 return getClass().getClassLoader();
146 }
147
148 /***
149 * Generate the <code>StringSwitcher</code>.
150 */
151 public StringSwitcher create() {
152 setNamePrefix(StringSwitcher.class.getName());
153 Object key = KEY_FACTORY.newInstance(strings, ints, fixedInput);
154 return (StringSwitcher)super.create(key);
155 }
156
157 public void generateClass(ClassVisitor v) throws Exception {
158 ClassEmitter ce = new ClassEmitter(v);
159 ce.begin_class(Constants.ACC_PUBLIC,
160 getClassName(),
161 STRING_SWITCHER,
162 null,
163 Constants.SOURCE_FILE);
164 EmitUtils.null_constructor(ce);
165 final CodeEmitter e = ce.begin_method(Constants.ACC_PUBLIC, INT_VALUE, null, null);
166 e.load_arg(0);
167 final List stringList = Arrays.asList(strings);
168 int style = fixedInput ? Constants.SWITCH_STYLE_HASHONLY : Constants.SWITCH_STYLE_HASH;
169 EmitUtils.string_switch(e, strings, style, new ObjectSwitchCallback() {
170 public void processCase(Object key, Label end) {
171 e.push(ints[stringList.indexOf(key)]);
172 e.return_value();
173 }
174 public void processDefault() {
175 e.push(-1);
176 e.return_value();
177 }
178 });
179 e.end_method();
180 ce.end_class();
181 }
182
183 protected Object firstInstance(Class type) {
184 return (StringSwitcher)ReflectUtils.newInstance(type);
185 }
186
187 protected Object nextInstance(Object instance) {
188 return instance;
189 }
190 }
191 }
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