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 */
017package org.apache.bcel.classfile;
018
019import java.io.DataInput;
020import java.io.DataOutputStream;
021import java.io.IOException;
022
023import org.apache.bcel.Const;
024
025/**
026 * This class is derived from <em>Attribute</em> and represents a reference to the source file of this class. At most
027 * one SourceFile attribute should appear per classfile. The intention of this class is that it is instantiated from the
028 * <em>Attribute.readAttribute()</em> method.
029 *
030 * @see Attribute
031 */
032public final class SourceFile extends Attribute {
033
034    private int sourceFileIndex;
035
036    /**
037     * Construct object from input stream.
038     *
039     * @param nameIndex Index in constant pool to CONSTANT_Utf8
040     * @param length Content length in bytes
041     * @param input Input stream
042     * @param constantPool Array of constants
043     * @throws IOException if an I/O error occurs.
044     */
045    SourceFile(final int nameIndex, final int length, final DataInput input, final ConstantPool constantPool) throws IOException {
046        this(nameIndex, length, input.readUnsignedShort(), constantPool);
047    }
048
049    /**
050     * @param nameIndex Index in constant pool to CONSTANT_Utf8, which should represent the string "SourceFile".
051     * @param length Content length in bytes, the value should be 2.
052     * @param constantPool The constant pool that this attribute is associated with.
053     * @param sourceFileIndex Index in constant pool to CONSTANT_Utf8. This string will be interpreted as the name of the
054     *        file from which this class was compiled. It will not be interpreted as indicating the name of the directory
055     *        contqining the file or an absolute path; this information has to be supplied the consumer of this attribute -
056     *        in many cases, the JVM.
057     */
058    public SourceFile(final int nameIndex, final int length, final int sourceFileIndex, final ConstantPool constantPool) {
059        super(Const.ATTR_SOURCE_FILE, nameIndex, length, constantPool);
060        this.sourceFileIndex = sourceFileIndex;
061    }
062
063    /**
064     * Initialize from another object. Note that both objects use the same references (shallow copy). Use clone() for a
065     * physical copy.
066     */
067    public SourceFile(final SourceFile c) {
068        this(c.getNameIndex(), c.getLength(), c.getSourceFileIndex(), c.getConstantPool());
069    }
070
071    /**
072     * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class.
073     * I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
074     *
075     * @param v Visitor object
076     */
077    @Override
078    public void accept(final Visitor v) {
079        v.visitSourceFile(this);
080    }
081
082    /**
083     * @return deep copy of this attribute
084     */
085    @Override
086    public Attribute copy(final ConstantPool constantPool) {
087        return (Attribute) clone();
088    }
089
090    /**
091     * Dump source file attribute to file stream in binary format.
092     *
093     * @param file Output file stream
094     * @throws IOException if an I/O error occurs.
095     */
096    @Override
097    public void dump(final DataOutputStream file) throws IOException {
098        super.dump(file);
099        file.writeShort(sourceFileIndex);
100    }
101
102    /**
103     * @return Index in constant pool of source file name.
104     */
105    public int getSourceFileIndex() {
106        return sourceFileIndex;
107    }
108
109    /**
110     * @return Source file name.
111     */
112    public String getSourceFileName() {
113        return super.getConstantPool().getConstantUtf8(sourceFileIndex).getBytes();
114    }
115
116    /**
117     * @param sourceFileIndex
118     */
119    public void setSourceFileIndex(final int sourceFileIndex) {
120        this.sourceFileIndex = sourceFileIndex;
121    }
122
123    /**
124     * @return String representation
125     */
126    @Override
127    public String toString() {
128        return "SourceFile: " + getSourceFileName();
129    }
130}