    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;
    023import java.util.Arrays;
    024
    025import org.apache.bcel.Const;
    026
    027/**
    028 * This class is derived from <em>Attribute</em> and represents the list of modules required, exported, opened or
    029 * provided by a module. There may be at most one Module attribute in a ClassFile structure.
    030 *
    031 * @see Attribute
    032 * @since 6.4.0
    033 */
    034public final class Module extends Attribute {
    035
    036    private final int moduleNameIndex;
    037    private final int moduleFlags;
    038    private final int moduleVersionIndex;
    039
    040    private ModuleRequires[] requiresTable;
    041    private ModuleExports[] exportsTable;
    042    private ModuleOpens[] opensTable;
    043    private final int usesCount;
    044    private final int[] usesIndex;
    045    private ModuleProvides[] providesTable;
    046
    047    /**
    048     * Construct object from input stream.
    049     *
    050     * @param nameIndex Index in constant pool
    051     * @param length Content length in bytes
    052     * @param input Input stream
    053     * @param constantPool Array of constants
    054     * @throws IOException if an I/O error occurs.
    055     */
    056    Module(final int nameIndex, final int length, final DataInput input, final ConstantPool constantPool) throws IOException {
    057        super(Const.ATTR_MODULE, nameIndex, length, constantPool);
    058
    059        moduleNameIndex = input.readUnsignedShort();
    060        moduleFlags = input.readUnsignedShort();
    061        moduleVersionIndex = input.readUnsignedShort();
    062
    063        final int requiresCount = input.readUnsignedShort();
    064        requiresTable = new ModuleRequires[requiresCount];
    065        for (int i = 0; i < requiresCount; i++) {
    066            requiresTable[i] = new ModuleRequires(input);
    067        }
    068
    069        final int exportsCount = input.readUnsignedShort();
    070        exportsTable = new ModuleExports[exportsCount];
    071        for (int i = 0; i < exportsCount; i++) {
    072            exportsTable[i] = new ModuleExports(input);
    073        }
    074
    075        final int opensCount = input.readUnsignedShort();
    076        opensTable = new ModuleOpens[opensCount];
    077        for (int i = 0; i < opensCount; i++) {
    078            opensTable[i] = new ModuleOpens(input);
    079        }
    080
    081        usesCount = input.readUnsignedShort();
    082        usesIndex = new int[usesCount];
    083        for (int i = 0; i < usesCount; i++) {
    084            usesIndex[i] = input.readUnsignedShort();
    085        }
    086
    087        final int providesCount = input.readUnsignedShort();
    088        providesTable = new ModuleProvides[providesCount];
    089        for (int i = 0; i < providesCount; i++) {
    090            providesTable[i] = new ModuleProvides(input);
    091        }
    092    }
    093
    094    /**
    095     * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class.
    096     * I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
    097     *
    098     * @param v Visitor object
    099     */
    100    @Override
    101    public void accept(final Visitor v) {
    102        v.visitModule(this);
    103    }
    104
    105    // TODO add more getters and setters?
    106
    107    /**
    108     * @return deep copy of this attribute
    109     */
    110    @Override
    111    public Attribute copy(final ConstantPool constantPool) {
    112        final Module c = (Module) clone();
    113
    114        c.requiresTable = new ModuleRequires[requiresTable.length];
    115        Arrays.setAll(c.requiresTable, i -> requiresTable[i].copy());
    116
    117        c.exportsTable = new ModuleExports[exportsTable.length];
    118        Arrays.setAll(c.exportsTable, i -> exportsTable[i].copy());
    119
    120        c.opensTable = new ModuleOpens[opensTable.length];
    121        Arrays.setAll(c.opensTable, i -> opensTable[i].copy());
    122
    123        c.providesTable = new ModuleProvides[providesTable.length];
    124        Arrays.setAll(c.providesTable, i -> providesTable[i].copy());
    125
    126        c.setConstantPool(constantPool);
    127        return c;
    128    }
    129
    130    /**
    131     * Dump Module attribute to file stream in binary format.
    132     *
    133     * @param file Output file stream
    134     * @throws IOException if an I/O error occurs.
    135     */
    136    @Override
    137    public void dump(final DataOutputStream file) throws IOException {
    138        super.dump(file);
    139
    140        file.writeShort(moduleNameIndex);
    141        file.writeShort(moduleFlags);
    142        file.writeShort(moduleVersionIndex);
    143
    144        file.writeShort(requiresTable.length);
    145        for (final ModuleRequires entry : requiresTable) {
    146            entry.dump(file);
    147        }
    148
    149        file.writeShort(exportsTable.length);
    150        for (final ModuleExports entry : exportsTable) {
    151            entry.dump(file);
    152        }
    153
    154        file.writeShort(opensTable.length);
    155        for (final ModuleOpens entry : opensTable) {
    156            entry.dump(file);
    157        }
    158
    159        file.writeShort(usesIndex.length);
    160        for (final int entry : usesIndex) {
    161            file.writeShort(entry);
    162        }
    163
    164        file.writeShort(providesTable.length);
    165        for (final ModuleProvides entry : providesTable) {
    166            entry.dump(file);
    167        }
    168    }
    169
    170    /**
    171     * @return table of exported interfaces
    172     * @see ModuleExports
    173     */
    174    public ModuleExports[] getExportsTable() {
    175        return exportsTable;
    176    }
    177
    178    /**
    179     * @return table of provided interfaces
    180     * @see ModuleOpens
    181     */
    182    public ModuleOpens[] getOpensTable() {
    183        return opensTable;
    184    }
    185
    186    /**
    187     * @return table of provided interfaces
    188     * @see ModuleProvides
    189     */
    190    public ModuleProvides[] getProvidesTable() {
    191        return providesTable;
    192    }
    193
    194    /**
    195     * @return table of required modules
    196     * @see ModuleRequires
    197     */
    198    public ModuleRequires[] getRequiresTable() {
    199        return requiresTable;
    200    }
    201
    202    /**
    203     * @return String representation, i.e., a list of packages.
    204     */
    205    @Override
    206    public String toString() {
    207        final ConstantPool cp = super.getConstantPool();
    208        final StringBuilder buf = new StringBuilder();
    209        buf.append("Module:\n");
    210        buf.append("  name:    ").append(Utility.pathToPackage(cp.getConstantString(moduleNameIndex, Const.CONSTANT_Module))).append("\n");
    211        buf.append("  flags:   ").append(String.format("%04x", moduleFlags)).append("\n");
    212        final String version = moduleVersionIndex == 0 ? "0" : cp.getConstantString(moduleVersionIndex, Const.CONSTANT_Utf8);
    213        buf.append("  version: ").append(version).append("\n");
    214
    215        buf.append("  requires(").append(requiresTable.length).append("):\n");
    216        for (final ModuleRequires module : requiresTable) {
    217            buf.append("    ").append(module.toString(cp)).append("\n");
    218        }
    219
    220        buf.append("  exports(").append(exportsTable.length).append("):\n");
    221        for (final ModuleExports module : exportsTable) {
    222            buf.append("    ").append(module.toString(cp)).append("\n");
    223        }
    224
    225        buf.append("  opens(").append(opensTable.length).append("):\n");
    226        for (final ModuleOpens module : opensTable) {
    227            buf.append("    ").append(module.toString(cp)).append("\n");
    228        }
    229
    230        buf.append("  uses(").append(usesIndex.length).append("):\n");
    231        for (final int index : usesIndex) {
    232            final String className = cp.getConstantString(index, Const.CONSTANT_Class);
    233            buf.append("    ").append(Utility.compactClassName(className, false)).append("\n");
    234        }
    235
    236        buf.append("  provides(").append(providesTable.length).append("):\n");
    237        for (final ModuleProvides module : providesTable) {
    238            buf.append("    ").append(module.toString(cp)).append("\n");
    239        }
    240
    241        return buf.substring(0, buf.length() - 1); // remove the last newline
    242    }
    243}