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.
028 * Each entry describes a module on which 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 requires_index;  // points to CONSTANT_Module_info
036    private final int requires_flags;
037    private final int requires_version_index;  // either 0 or points to CONSTANT_Utf8_info
038
039
040    /**
041     * Construct object from file stream.
042     *
043     * @param file Input stream
044     * @throws IOException if an I/O Exception occurs in readUnsignedShort
045     */
046    ModuleRequires(final DataInput file) throws IOException {
047        requires_index = file.readUnsignedShort();
048        requires_flags = file.readUnsignedShort();
049        requires_version_index = file.readUnsignedShort();
050    }
051
052
053    /**
054     * Called by objects that are traversing the nodes of the tree implicitely
055     * defined by the contents of a Java class. I.e., the hierarchy of methods,
056     * fields, attributes, etc. spawns a tree of objects.
057     *
058     * @param v Visitor object
059     */
060    @Override
061    public void accept( final Visitor v ) {
062        v.visitModuleRequires(this);
063    }
064
065    // TODO add more getters and setters?
066
067    /**
068     * Dump table entry to file stream in binary format.
069     *
070     * @param file Output file stream
071     * @throws IOException if an I/O Exception occurs in writeShort
072     */
073    public void dump( final DataOutputStream file ) throws IOException {
074        file.writeShort(requires_index);
075        file.writeShort(requires_flags);
076        file.writeShort(requires_version_index);
077    }
078
079
080    /**
081     * @return String representation
082     */
083    @Override
084    public String toString() {
085        return "requires(" + requires_index + ", " + String.format("%04x", requires_flags) + ", " + requires_version_index + ")";
086    }
087
088
089    /**
090     * @return Resolved string representation
091     */
092    public String toString( final ConstantPool constant_pool ) {
093        final StringBuilder buf = new StringBuilder();
094        final String module_name = constant_pool.constantToString(requires_index, Const.CONSTANT_Module);
095        buf.append(Utility.compactClassName(module_name, false));
096        buf.append(", ").append(String.format("%04x", requires_flags));
097        final String version = requires_version_index == 0 ? "0" : constant_pool.getConstantString(requires_version_index, Const.CONSTANT_Utf8);
098        buf.append(", ").append(version);
099        return buf.toString();
100    }
101
102
103    /**
104     * @return deep copy of this object
105     */
106    public ModuleRequires copy() {
107        try {
108            return (ModuleRequires) clone();
109        } catch (final CloneNotSupportedException e) {
110            // TODO should this throw?
111        }
112        return null;
113    }
114}