    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}