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comparison src/com/go/trove/classfile/Attribute.java @ 0:3dc0c5604566

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Initial checkin of blitz 2.0 fcs - no installer yet.
author Dan Creswell <dan.creswell@gmail.com>
date Sat, 21 Mar 2009 11:00:06 +0000
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1 /* ====================================================================
2 * Trove - Copyright (c) 1997-2000 Walt Disney Internet Group
3 * ====================================================================
4 * The Tea Software License, Version 1.1
5 *
6 * Copyright (c) 2000 Walt Disney Internet Group. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 *
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in
17 * the documentation and/or other materials provided with the
18 * distribution.
19 *
20 * 3. The end-user documentation included with the redistribution,
21 * if any, must include the following acknowledgment:
22 * "This product includes software developed by the
23 * Walt Disney Internet Group (http://opensource.go.com/)."
24 * Alternately, this acknowledgment may appear in the software itself,
25 * if and wherever such third-party acknowledgments normally appear.
26 *
27 * 4. The names "Tea", "TeaServlet", "Kettle", "Trove" and "BeanDoc" must
28 * not be used to endorse or promote products derived from this
29 * software without prior written permission. For written
30 * permission, please contact opensource@dig.com.
31 *
32 * 5. Products derived from this software may not be called "Tea",
33 * "TeaServlet", "Kettle" or "Trove", nor may "Tea", "TeaServlet",
34 * "Kettle", "Trove" or "BeanDoc" appear in their name, without prior
35 * written permission of the Walt Disney Internet Group.
36 *
37 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
38 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
39 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
40 * DISCLAIMED. IN NO EVENT SHALL THE WALT DISNEY INTERNET GROUP OR ITS
41 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
42 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
43 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
44 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
45 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
46 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
47 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
48 * ====================================================================
49 *
50 * For more information about Tea, please see http://opensource.go.com/.
51 */
52
53 package com.go.trove.classfile;
54
55 import java.io.*;
56
57 /******************************************************************************
58 * This class corresponds to the attribute_info structure defined in section
59 * 4.7 of <i>The Java Virtual Machine Specification</i>.
60 *
61 * @author Brian S O'Neill
62 * @version
63 * <!--$$Revision: 1.1 $-->, <!--$$JustDate:--> 00/11/27 <!-- $-->
64 * @see ClassFile
65 */
66 public abstract class Attribute {
67 final static Attribute[] NO_ATTRIBUTES = new Attribute[0];
68
69 final static String CODE = "Code";
70 final static String CONSTANT_VALUE = "ConstantValue";
71 final static String DEPRECATED = "Deprecated";
72 final static String EXCEPTIONS = "Exceptions";
73 final static String INNER_CLASSES = "InnerClasses";
74 final static String LINE_NUMBER_TABLE = "LineNumberTable";
75 final static String LOCAL_VARIABLE_TABLE = "LocalVariableTable";
76 final static String SOURCE_FILE = "SourceFile";
77 final static String SYNTHETIC = "Synthetic";
78
79 /** The ConstantPool that this attribute is defined against. */
80 protected final ConstantPool mCp;
81
82 private String mName;
83 private ConstantUTFInfo mNameConstant;
84
85 protected Attribute(ConstantPool cp, String name) {
86 mCp = cp;
87 mName = name;
88 mNameConstant = ConstantUTFInfo.make(cp, name);
89 }
90
91 /**
92 * Returns the ConstantPool that this attribute is defined against.
93 */
94 public ConstantPool getConstantPool() {
95 return mCp;
96 }
97
98 /**
99 * Returns the name of this attribute.
100 */
101 public String getName() {
102 return mName;
103 }
104
105 public ConstantUTFInfo getNameConstant() {
106 return mNameConstant;
107 }
108
109 /**
110 * Some attributes have sub-attributes. Default implementation returns an
111 * empty array.
112 */
113 public Attribute[] getAttributes() {
114 return NO_ATTRIBUTES;
115 }
116
117 /**
118 * Returns the length (in bytes) of this attribute in the class file.
119 */
120 public abstract int getLength();
121
122 /**
123 * This method writes the 16 bit name constant index followed by the
124 * 32 bit attribute length, followed by the attribute specific data.
125 */
126 public final void writeTo(DataOutput dout) throws IOException {
127 dout.writeShort(mNameConstant.getIndex());
128 dout.writeInt(getLength());
129 writeDataTo(dout);
130 }
131
132 /**
133 * Write just the attribute specific data. The default implementation
134 * writes nothing.
135 */
136 public void writeDataTo(DataOutput dout) throws IOException {
137 }
138
139 /**
140 * @param attrFactory optional factory for reading custom attributes
141 */
142 public static Attribute readFrom(ConstantPool cp,
143 DataInput din,
144 AttributeFactory attrFactory)
145 throws IOException
146 {
147 int index = din.readUnsignedShort();
148 String name = ((ConstantUTFInfo)cp.getConstant(index)).getValue();
149 int length = din.readInt();
150
151 attrFactory = new Factory(attrFactory);
152 return attrFactory.createAttribute(cp, name, length, din);
153 }
154
155 private static class Factory implements AttributeFactory {
156 private final AttributeFactory mAttrFactory;
157
158 public Factory(AttributeFactory attrFactory) {
159 mAttrFactory = attrFactory;
160 }
161
162 public Attribute createAttribute(ConstantPool cp,
163 String name,
164 final int length,
165 DataInput din) throws IOException {
166 if (name.equals(CODE)) {
167 return CodeAttr.define(cp, name, length, din, mAttrFactory);
168 }
169 else if (name.equals(CONSTANT_VALUE)) {
170 return ConstantValueAttr.define(cp, name, length, din);
171 }
172 else if (name.equals(DEPRECATED)) {
173 return DeprecatedAttr.define(cp, name, length, din);
174 }
175 else if (name.equals(EXCEPTIONS)) {
176 return ExceptionsAttr.define(cp, name, length, din);
177 }
178 else if (name.equals(INNER_CLASSES)) {
179 return InnerClassesAttr.define(cp, name, length, din);
180 }
181 else if (name.equals(LINE_NUMBER_TABLE)) {
182 return LineNumberTableAttr.define(cp, name, length, din);
183 }
184 else if (name.equals(LOCAL_VARIABLE_TABLE)) {
185 return LocalVariableTableAttr.define
186 (cp, name, length, din);
187 }
188 else if (name.equals(SOURCE_FILE)) {
189 return SourceFileAttr.define(cp, name, length, din);
190 }
191 else if (name.equals(SYNTHETIC)) {
192 return SyntheticAttr.define(cp, name, length, din);
193 }
194
195 if (mAttrFactory != null) {
196 Attribute attr =
197 mAttrFactory.createAttribute(cp, name, length, din);
198 if (attr != null) {
199 return attr;
200 }
201 }
202
203 // Default case, return attribute that captures the data, but
204 // doesn't decode it.
205
206 final byte[] data = new byte[length];
207 din.readFully(data);
208
209 return new Attribute(cp, name) {
210 public int getLength() {
211 return length;
212 }
213
214 public void writeDataTo(DataOutput dout) throws IOException {
215 dout.write(data);
216 }
217 };
218 }
219 }
220 }