1 /*
2 * reserved comment block
3 * DO NOT REMOVE OR ALTER!
4 */
5 /*
6 * Licensed to the Apache Software Foundation (ASF) under one or more
7 * contributor license agreements. See the NOTICE file distributed with
8 * this work for additional information regarding copyright ownership.
9 * The ASF licenses this file to You under the Apache License, Version 2.0
10 * (the "License"); you may not use this file except in compliance with
11 * the License. You may obtain a copy of the License at
12 *
13 * http://www.apache.org/licenses/LICENSE-2.0
14 *
15 * Unless required by applicable law or agreed to in writing, software
16 * distributed under the License is distributed on an "AS IS" BASIS,
17 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
18 * See the License for the specific language governing permissions and
19 * limitations under the License.
20 */
21
22 package com.sun.org.apache.bcel.internal.classfile;
23
24
25 import com.sun.org.apache.bcel.internal.Constants;
26 import java.io.*;
27 import java.util.*;
28
29 /**
30 * This class represents a reference to an unknown (i.e.,
31 * application-specific) attribute of a class. It is instantiated from the
32 * <em>Attribute.readAttribute()</em> method. Applications that need to
33 * read in application-specific attributes should create an <a
34 * href="./AttributeReader.html">AttributeReader</a> implementation and
35 * attach it via <a
36 * href="./Attribute.html#addAttributeReader(java.lang.String,
37 * com.sun.org.apache.bcel.internal.classfile.AttributeReader)">Attribute.addAttributeReader</a>.
38
39 *
40 * @see com.sun.org.apache.bcel.internal.classfile.Attribute
41 * @see com.sun.org.apache.bcel.internal.classfile.AttributeReader
42 * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
43 */
44 public final class Unknown extends Attribute {
45 private byte[] bytes;
46 private String name;
47
48 private static HashMap unknown_attributes = new HashMap();
49
50 /** @return array of unknown attributes, but just one for each kind.
51 */
52 static Unknown[] getUnknownAttributes() {
53 Unknown[] unknowns = new Unknown[unknown_attributes.size()];
54 Iterator entries = unknown_attributes.values().iterator();
55
56 for(int i=0; entries.hasNext(); i++)
57 unknowns[i] = (Unknown)entries.next();
58
59 unknown_attributes.clear();
60 return unknowns;
61 }
62
63 /**
64 * Initialize from another object. Note that both objects use the same
65 * references (shallow copy). Use clone() for a physical copy.
66 */
67 public Unknown(Unknown c) {
68 this(c.getNameIndex(), c.getLength(), c.getBytes(), c.getConstantPool());
69 }
70
71 /**
72 * Create a non-standard attribute.
73 *
74 * @param name_index Index in constant pool
75 * @param length Content length in bytes
76 * @param bytes Attribute contents
77 * @param constant_pool Array of constants
78 */
79 public Unknown(int name_index, int length, byte[] bytes,
80 ConstantPool constant_pool)
81 {
82 super(Constants.ATTR_UNKNOWN, name_index, length, constant_pool);
83 this.bytes = bytes;
84
85 name = ((ConstantUtf8)constant_pool.getConstant(name_index,
86 Constants.CONSTANT_Utf8)).getBytes();
87 unknown_attributes.put(name, this);
88 }
89
90 /**
91 * Construct object from file stream.
92 * @param name_index Index in constant pool
93 * @param length Content length in bytes
94 * @param file Input stream
95 * @param constant_pool Array of constants
96 * @throws IOException
97 */
98 Unknown(int name_index, int length, DataInputStream file,
99 ConstantPool constant_pool)
100 throws IOException
101 {
102 this(name_index, length, (byte [])null, constant_pool);
103
104 if(length > 0) {
105 bytes = new byte[length];
106 file.readFully(bytes);
107 }
108 }
109
110 /**
111 * Called by objects that are traversing the nodes of the tree implicitely
112 * defined by the contents of a Java class. I.e., the hierarchy of methods,
113 * fields, attributes, etc. spawns a tree of objects.
114 *
115 * @param v Visitor object
116 */
117 public void accept(Visitor v) {
118 v.visitUnknown(this);
119 }
120 /**
121 * Dump unknown bytes to file stream.
122 *
123 * @param file Output file stream
124 * @throws IOException
125 */
126 public final void dump(DataOutputStream file) throws IOException
127 {
128 super.dump(file);
129 if(length > 0)
130 file.write(bytes, 0, length);
131 }
132 /**
133 * @return data bytes.
134 */
135 public final byte[] getBytes() { return bytes; }
136
137 /**
138 * @return name of attribute.
139 */
140 public final String getName() { return name; }
141
142 /**
143 * @param bytes.
144 */
145 public final void setBytes(byte[] bytes) {
146 this.bytes = bytes;
147 }
148
149 /**
150 * @return String representation.
151 */
152 public final String toString() {
153 if(length == 0 || bytes == null)
154 return "(Unknown attribute " + name + ")";
155
156 String hex;
157 if(length > 10) {
158 byte[] tmp = new byte[10];
159 System.arraycopy(bytes, 0, tmp, 0, 10);
160 hex = Utility.toHexString(tmp) + "... (truncated)";
161 }
162 else
163 hex = Utility.toHexString(bytes);
164
165 return "(Unknown attribute " + name + ": " + hex + ")";
166 }
167
168 /**
169 * @return deep copy of this attribute
170 */
171 public Attribute copy(ConstantPool constant_pool) {
172 Unknown c = (Unknown)clone();
173
174 if(bytes != null)
175 c.bytes = (byte[])bytes.clone();
176
177 c.constant_pool = constant_pool;
178 return c;
179 }
180 }