1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.bcel.classfile;
18
19 import java.io.DataInput;
20 import java.io.DataOutputStream;
21 import java.io.IOException;
22
23 import org.apache.bcel.Const;
24 import org.apache.bcel.util.Args;
25
26 /**
27 * This class is derived from <em>Attribute</em> and represents a reference to the source file of this class. At most
28 * one SourceFile attribute should appear per classfile. The intention of this class is that it is instantiated from the
29 * <em>Attribute.readAttribute()</em> method.
30 *
31 * @see Attribute
32 */
33 public final class SourceFile extends Attribute {
34
35 private int sourceFileIndex;
36
37 /**
38 * Constructs object from input stream.
39 *
40 * @param nameIndex Index in constant pool to CONSTANT_Utf8
41 * @param length Content length in bytes
42 * @param input Input stream
43 * @param constantPool Array of constants
44 * @throws IOException if an I/O error occurs.
45 */
46 SourceFile(final int nameIndex, final int length, final DataInput input, final ConstantPool constantPool) throws IOException {
47 this(nameIndex, length, input.readUnsignedShort(), constantPool);
48 }
49
50 /**
51 * @param nameIndex Index in constant pool to CONSTANT_Utf8, which should represent the string "SourceFile".
52 * @param length Content length in bytes, the value should be 2.
53 * @param constantPool The constant pool that this attribute is associated with.
54 * @param sourceFileIndex Index in constant pool to CONSTANT_Utf8. This string will be interpreted as the name of the
55 * file from which this class was compiled. It will not be interpreted as indicating the name of the directory
56 * contqining the file or an absolute path; this information has to be supplied the consumer of this attribute -
57 * in many cases, the JVM.
58 */
59 public SourceFile(final int nameIndex, final int length, final int sourceFileIndex, final ConstantPool constantPool) {
60 super(Const.ATTR_SOURCE_FILE, nameIndex, Args.require(length, 2, "SourceFile length attribute"), constantPool);
61 this.sourceFileIndex = Args.requireU2(sourceFileIndex, 0, constantPool.getLength(), "SourceFile source file index");
62 }
63
64 /**
65 * Initialize from another object. Note that both objects use the same references (shallow copy). Use clone() for a
66 * physical copy.
67 *
68 * @param c Source to copy.
69 */
70 public SourceFile(final SourceFile c) {
71 this(c.getNameIndex(), c.getLength(), c.getSourceFileIndex(), c.getConstantPool());
72 }
73
74 /**
75 * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class.
76 * I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
77 *
78 * @param v Visitor object
79 */
80 @Override
81 public void accept(final Visitor v) {
82 v.visitSourceFile(this);
83 }
84
85 /**
86 * @return deep copy of this attribute
87 */
88 @Override
89 public Attribute copy(final ConstantPool constantPool) {
90 return (Attribute) clone();
91 }
92
93 /**
94 * Dump source file attribute to file stream in binary format.
95 *
96 * @param file Output file stream
97 * @throws IOException if an I/O error occurs.
98 */
99 @Override
100 public void dump(final DataOutputStream file) throws IOException {
101 super.dump(file);
102 file.writeShort(sourceFileIndex);
103 }
104
105 /**
106 * @return Index in constant pool of source file name.
107 */
108 public int getSourceFileIndex() {
109 return sourceFileIndex;
110 }
111
112 /**
113 * @return Source file name.
114 */
115 public String getSourceFileName() {
116 return super.getConstantPool().getConstantUtf8(sourceFileIndex).getBytes();
117 }
118
119 /**
120 * @param sourceFileIndex
121 */
122 public void setSourceFileIndex(final int sourceFileIndex) {
123 this.sourceFileIndex = sourceFileIndex;
124 }
125
126 /**
127 * @return String representation
128 */
129 @Override
130 public String toString() {
131 return "SourceFile: " + getSourceFileName();
132 }
133 }