    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;
    024import org.apache.bcel.util.Args;
    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     * Constructs object from input stream.
    039     *
    040     * @param nameIndex Index in constant pool to CONSTANT_Utf8
    041     * @param length Content length in bytes
    042     * @param input Input stream
    043     * @param constantPool Array of constants
    044     * @throws IOException if an I/O error occurs.
    045     */
    046    SourceFile(final int nameIndex, final int length, final DataInput input, final ConstantPool constantPool) throws IOException {
    047        this(nameIndex, length, input.readUnsignedShort(), constantPool);
    048    }
    049
    050    /**
    051     * @param nameIndex 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 nameIndex, final int length, final int sourceFileIndex, final ConstantPool constantPool) {
    060        super(Const.ATTR_SOURCE_FILE, nameIndex, Args.require(length, 2, "SourceFile length attribute"), constantPool);
    061        this.sourceFileIndex = Args.requireU2(sourceFileIndex, 0, constantPool.getLength(), "SourceFile source file index");
    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     * @param c Source to copy.
    069     */
    070    public SourceFile(final SourceFile c) {
    071        this(c.getNameIndex(), c.getLength(), c.getSourceFileIndex(), c.getConstantPool());
    072    }
    073
    074    /**
    075     * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class.
    076     * I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
    077     *
    078     * @param v Visitor object
    079     */
    080    @Override
    081    public void accept(final Visitor v) {
    082        v.visitSourceFile(this);
    083    }
    084
    085    /**
    086     * @return deep copy of this attribute
    087     */
    088    @Override
    089    public Attribute copy(final ConstantPool constantPool) {
    090        return (Attribute) clone();
    091    }
    092
    093    /**
    094     * Dump source file attribute to file stream in binary format.
    095     *
    096     * @param file Output file stream
    097     * @throws IOException if an I/O error occurs.
    098     */
    099    @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}