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 represents an entry in the requires table of the Module attribute. Each entry describes a module on which
028 * the parent module depends.
029 *
030 * @see Module
031 * @since 6.4.0
032 */
033public final class ModuleRequires implements Cloneable, Node {
034
035    private final int requiresIndex; // points to CONSTANT_Module_info
036    private final int requiresFlags;
037    private final int requiresVersionIndex; // either 0 or points to CONSTANT_Utf8_info
038
039    /**
040     * Constructs object from file stream.
041     *
042     * @param file Input stream
043     * @throws IOException if an I/O Exception occurs in readUnsignedShort
044     */
045    ModuleRequires(final DataInput file) throws IOException {
046        requiresIndex = file.readUnsignedShort();
047        requiresFlags = file.readUnsignedShort();
048        requiresVersionIndex = file.readUnsignedShort();
049    }
050
051    /**
052     * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class.
053     * I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
054     *
055     * @param v Visitor object
056     */
057    @Override
058    public void accept(final Visitor v) {
059        v.visitModuleRequires(this);
060    }
061
062    // TODO add more getters and setters?
063
064    /**
065     * @return deep copy of this object
066     */
067    public ModuleRequires copy() {
068        try {
069            return (ModuleRequires) clone();
070        } catch (final CloneNotSupportedException e) {
071            // TODO should this throw?
072        }
073        return null;
074    }
075
076    /**
077     * Dump table entry to file stream in binary format.
078     *
079     * @param file Output file stream
080     * @throws IOException if an I/O Exception occurs in writeShort
081     */
082    public void dump(final DataOutputStream file) throws IOException {
083        file.writeShort(requiresIndex);
084        file.writeShort(requiresFlags);
085        file.writeShort(requiresVersionIndex);
086    }
087
088    /**
089     * @return String representation
090     */
091    @Override
092    public String toString() {
093        return "requires(" + requiresIndex + ", " + String.format("%04x", requiresFlags) + ", " + requiresVersionIndex + ")";
094    }
095
096    /**
097     * @return Resolved string representation
098     */
099    public String toString(final ConstantPool constantPool) {
100        final StringBuilder buf = new StringBuilder();
101        final String moduleName = constantPool.constantToString(requiresIndex, Const.CONSTANT_Module);
102        buf.append(Utility.compactClassName(moduleName, false));
103        buf.append(", ").append(String.format("%04x", requiresFlags));
104        final String version = requiresVersionIndex == 0 ? "0" : constantPool.getConstantString(requiresVersionIndex, Const.CONSTANT_Utf8);
105        buf.append(", ").append(version);
106        return buf.toString();
107    }
108}