001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 *  Unless required by applicable law or agreed to in writing, software
012 *  distributed under the License is distributed on an "AS IS" BASIS,
013 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 *  See the License for the specific language governing permissions and
015 *  limitations under the License.
016 *
017 */
018package org.apache.bcel.classfile;
019
020import java.io.DataInput;
021import java.io.DataOutputStream;
022import java.io.IOException;
023
024import org.apache.bcel.Const;
025
026/**
027 * This class is derived from <em>Attribute</em> and represents a reference to the source file of this class. At most
028 * one SourceFile attribute should appear per classfile. The intention of this class is that it is instantiated from the
029 * <em>Attribute.readAttribute()</em> method.
030 *
031 * @see Attribute
032 */
033public final class SourceFile extends Attribute {
034
035    private int sourceFileIndex;
036
037    /**
038     * Construct object from input stream.
039     *
040     * @param name_index Index in constant pool to CONSTANT_Utf8
041     * @param length Content length in bytes
042     * @param input Input stream
043     * @param constant_pool Array of constants
044     * @throws IOException if an I/O error occurs.
045     */
046    SourceFile(final int name_index, final int length, final DataInput input, final ConstantPool constant_pool) throws IOException {
047        this(name_index, length, input.readUnsignedShort(), constant_pool);
048    }
049
050    /**
051     * @param name_index Index in constant pool to CONSTANT_Utf8, which should represent the string "SourceFile".
052     * @param length Content length in bytes, the value should be 2.
053     * @param constantPool The constant pool that this attribute is associated with.
054     * @param sourceFileIndex Index in constant pool to CONSTANT_Utf8. This string will be interpreted as the name of the
055     *        file from which this class was compiled. It will not be interpreted as indicating the name of the directory
056     *        contqining the file or an absolute path; this information has to be supplied the consumer of this attribute -
057     *        in many cases, the JVM.
058     */
059    public SourceFile(final int name_index, final int length, final int sourceFileIndex, final ConstantPool constantPool) {
060        super(Const.ATTR_SOURCE_FILE, name_index, length, constantPool);
061        this.sourceFileIndex = sourceFileIndex;
062    }
063
064    /**
065     * Initialize from another object. Note that both objects use the same references (shallow copy). Use clone() for a
066     * physical copy.
067     */
068    public SourceFile(final SourceFile c) {
069        this(c.getNameIndex(), c.getLength(), c.getSourceFileIndex(), c.getConstantPool());
070    }
071
072    /**
073     * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class.
074     * I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
075     *
076     * @param v Visitor object
077     */
078    @Override
079    public void accept(final Visitor v) {
080        v.visitSourceFile(this);
081    }
082
083    /**
084     * @return deep copy of this attribute
085     */
086    @Override
087    public Attribute copy(final ConstantPool constantPool) {
088        return (Attribute) clone();
089    }
090
091    /**
092     * Dump source file attribute to file stream in binary format.
093     *
094     * @param file Output file stream
095     * @throws IOException if an I/O error occurs.
096     */
097    @Override
098    public void dump(final DataOutputStream file) throws IOException {
099        super.dump(file);
100        file.writeShort(sourceFileIndex);
101    }
102
103    /**
104     * @return Index in constant pool of source file name.
105     */
106    public int getSourceFileIndex() {
107        return sourceFileIndex;
108    }
109
110    /**
111     * @return Source file name.
112     */
113    public String getSourceFileName() {
114        return super.getConstantPool().getConstantUtf8(sourceFileIndex).getBytes();
115    }
116
117    /**
118     * @param sourceFileIndex
119     */
120    public void setSourceFileIndex(final int sourceFileIndex) {
121        this.sourceFileIndex = sourceFileIndex;
122    }
123
124    /**
125     * @return String representation
126     */
127    @Override
128    public String toString() {
129        return "SourceFile: " + getSourceFileName();
130    }
131}