1 package org.apache.bcel.classfile;
2
3 /* ====================================================================
4 * The Apache Software License, Version 1.1
5 *
6 * Copyright (c) 2001 The Apache Software Foundation. All rights
7 * reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 *
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 *
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in
18 * the documentation and/or other materials provided with the
19 * distribution.
20 *
21 * 3. The end-user documentation included with the redistribution,
22 * if any, must include the following acknowledgment:
23 * "This product includes software developed by the
24 * Apache Software Foundation (http://www.apache.org/)."
25 * Alternately, this acknowledgment may appear in the software itself,
26 * if and wherever such third-party acknowledgments normally appear.
27 *
28 * 4. The names "Apache" and "Apache Software Foundation" and
29 * "Apache BCEL" must not be used to endorse or promote products
30 * derived from this software without prior written permission. For
31 * written permission, please contact apache@apache.org.
32 *
33 * 5. Products derived from this software may not be called "Apache",
34 * "Apache BCEL", nor may "Apache" appear in their name, without
35 * prior written permission of the Apache Software Foundation.
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 APACHE SOFTWARE FOUNDATION OR
41 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
42 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
43 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
44 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
45 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
46 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
47 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
48 * SUCH DAMAGE.
49 * ====================================================================
50 *
51 * This software consists of voluntary contributions made by many
52 * individuals on behalf of the Apache Software Foundation. For more
53 * information on the Apache Software Foundation, please see
54 * <http://www.apache.org/>.
55 */
56
57 import org.apache.bcel.Constants;
58 import java.io.*;
59 import java.util.*;
60
61 /***
62 * This class represents a reference to an unknown (i.e.,
63 * application-specific) attribute of a class. It is instantiated from the
64 * <em>Attribute.readAttribute()</em> method. Applications that need to
65 * read in application-specific attributes should create an <a
66 * href="./AttributeReader.html">AttributeReader</a> implementation and
67 * attach it via <a
68 * href="./Attribute.html#addAttributeReader(java.lang.String,
69 * org.apache.bcel.classfile.AttributeReader)">Attribute.addAttributeReader</a>.
70
71 *
72 * @version $Id: Unknown.java,v 1.3 2002/03/11 16:16:35 mdahm Exp $
73 * @see org.apache.bcel.classfile.Attribute
74 * @see org.apache.bcel.classfile.AttributeReader
75 * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
76 */
77 public final class Unknown extends Attribute {
78 private byte[] bytes;
79 private String name;
80
81 private static HashMap unknown_attributes = new HashMap();
82
83 /*** @return array of unknown attributes, but just one for each kind.
84 */
85 static Unknown[] getUnknownAttributes() {
86 Unknown[] unknowns = new Unknown[unknown_attributes.size()];
87 Iterator entries = unknown_attributes.values().iterator();
88
89 for(int i=0; entries.hasNext(); i++)
90 unknowns[i] = (Unknown)entries.next();
91
92 unknown_attributes.clear();
93 return unknowns;
94 }
95
96 /***
97 * Initialize from another object. Note that both objects use the same
98 * references (shallow copy). Use clone() for a physical copy.
99 */
100 public Unknown(Unknown c) {
101 this(c.getNameIndex(), c.getLength(), c.getBytes(), c.getConstantPool());
102 }
103
104 /***
105 * Create a non-standard attribute.
106 *
107 * @param name_index Index in constant pool
108 * @param length Content length in bytes
109 * @param bytes Attribute contents
110 * @param constant_pool Array of constants
111 */
112 public Unknown(int name_index, int length, byte[] bytes,
113 ConstantPool constant_pool)
114 {
115 super(Constants.ATTR_UNKNOWN, name_index, length, constant_pool);
116 this.bytes = bytes;
117
118 name = ((ConstantUtf8)constant_pool.getConstant(name_index,
119 Constants.CONSTANT_Utf8)).getBytes();
120 unknown_attributes.put(name, this);
121 }
122
123 /***
124 * Construct object from file stream.
125 * @param name_index Index in constant pool
126 * @param length Content length in bytes
127 * @param file Input stream
128 * @param constant_pool Array of constants
129 * @throws IOException
130 */
131 Unknown(int name_index, int length, DataInputStream file,
132 ConstantPool constant_pool)
133 throws IOException
134 {
135 this(name_index, length, (byte [])null, constant_pool);
136
137 if(length > 0) {
138 bytes = new byte[length];
139 file.readFully(bytes);
140 }
141 }
142
143 /***
144 * Called by objects that are traversing the nodes of the tree implicitely
145 * defined by the contents of a Java class. I.e., the hierarchy of methods,
146 * fields, attributes, etc. spawns a tree of objects.
147 *
148 * @param v Visitor object
149 */
150 public void accept(Visitor v) {
151 v.visitUnknown(this);
152 }
153 /***
154 * Dump unknown bytes to file stream.
155 *
156 * @param file Output file stream
157 * @throws IOException
158 */
159 public final void dump(DataOutputStream file) throws IOException
160 {
161 super.dump(file);
162 if(length > 0)
163 file.write(bytes, 0, length);
164 }
165 /***
166 * @return data bytes.
167 */
168 public final byte[] getBytes() { return bytes; }
169
170 /***
171 * @return name of attribute.
172 */
173 public final String getName() { return name; }
174
175 /***
176 * @param bytes.
177 */
178 public final void setBytes(byte[] bytes) {
179 this.bytes = bytes;
180 }
181
182 /***
183 * @return String representation.
184 */
185 public final String toString() {
186 if(length == 0 || bytes == null)
187 return "(Unknown attribute " + name + ")";
188
189 String hex;
190 if(length > 10) {
191 byte[] tmp = new byte[10];
192 System.arraycopy(bytes, 0, tmp, 0, 10);
193 hex = Utility.toHexString(tmp) + "... (truncated)";
194 }
195 else
196 hex = Utility.toHexString(bytes);
197
198 return "(Unknown attribute " + name + ": " + hex + ")";
199 }
200
201 /***
202 * @return deep copy of this attribute
203 */
204 public Attribute copy(ConstantPool constant_pool) {
205 Unknown c = (Unknown)clone();
206
207 if(bytes != null)
208 c.bytes = (byte[])bytes.clone();
209
210 c.constant_pool = constant_pool;
211 return c;
212 }
213 }
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