    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 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    /**
    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        requiresIndex = file.readUnsignedShort();
    048        requiresFlags = file.readUnsignedShort();
    049        requiresVersionIndex = 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(requiresIndex);
    075        file.writeShort(requiresFlags);
    076        file.writeShort(requiresVersionIndex);
    077    }
    078
    079
    080    /**
    081     * @return String representation
    082     */
    083    @Override
    084    public String toString() {
    085        return "requires(" + requiresIndex + ", " + String.format("%04x", requiresFlags) + ", " + requiresVersionIndex + ")";
    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(requiresIndex, Const.CONSTANT_Module);
    095        buf.append(Utility.compactClassName(module_name, false));
    096        buf.append(", ").append(String.format("%04x", requiresFlags));
    097        final String version = requiresVersionIndex == 0 ? "0" : constant_pool.getConstantString(requiresVersionIndex, 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}