    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 exports table of the Module attribute. Each entry describes a package which may
    028 * open the parent module.
    029 *
    030 * @see Module
    031 * @since 6.4.0
    032 */
    033public final class ModuleExports implements Cloneable, Node {
    034
    035    private static String getToModuleNameAtIndex(final ConstantPool constantPool, final int index) {
    036        return constantPool.getConstantString(index, Const.CONSTANT_Module);
    037    }
    038    private final int exportsIndex; // points to CONSTANT_Package_info
    039    private final int exportsFlags;
    040    private final int exportsToCount;
    041
    042    private final int[] exportsToIndex; // points to CONSTANT_Module_info
    043
    044    /**
    045     * Constructs object from file stream.
    046     *
    047     * @param file Input stream
    048     * @throws IOException if an I/O Exception occurs in readUnsignedShort
    049     */
    050    ModuleExports(final DataInput file) throws IOException {
    051        exportsIndex = file.readUnsignedShort();
    052        exportsFlags = file.readUnsignedShort();
    053        exportsToCount = file.readUnsignedShort();
    054        exportsToIndex = new int[exportsToCount];
    055        for (int i = 0; i < exportsToCount; i++) {
    056            exportsToIndex[i] = file.readUnsignedShort();
    057        }
    058    }
    059
    060    /**
    061     * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class.
    062     * I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
    063     *
    064     * @param v Visitor object
    065     */
    066    @Override
    067    public void accept(final Visitor v) {
    068        v.visitModuleExports(this);
    069    }
    070
    071    /**
    072     * @return deep copy of this object
    073     */
    074    public ModuleExports copy() {
    075        try {
    076            return (ModuleExports) clone();
    077        } catch (final CloneNotSupportedException e) {
    078            // TODO should this throw?
    079        }
    080        return null;
    081    }
    082
    083    /**
    084     * Dump table entry to file stream in binary format.
    085     *
    086     * @param file Output file stream
    087     * @throws IOException if an I/O Exception occurs in writeShort
    088     */
    089    public void dump(final DataOutputStream file) throws IOException {
    090        file.writeShort(exportsIndex);
    091        file.writeShort(exportsFlags);
    092        file.writeShort(exportsToCount);
    093        for (final int entry : exportsToIndex) {
    094            file.writeShort(entry);
    095        }
    096    }
    097
    098    /**
    099     * Gets the flags for this ModuleExports.
    100     * @return the exportsFlags
    101     * @since 6.10.0
    102     */
    103    public int getExportsFlags() {
    104        return exportsFlags;
    105    }
    106
    107    /**
    108     * Gets the exported package name.
    109     * @param constantPool the constant pool from the ClassFile
    110     * @return the exported package name
    111     * @since 6.10.0
    112     */
    113    public String getPackageName(final ConstantPool constantPool) {
    114        return constantPool.constantToString(exportsIndex, Const.CONSTANT_Package);
    115    }
    116
    117    /**
    118     * Gets an array of module names for this ModuleExports.
    119     * @param constantPool Array of constants usually obtained from the ClassFile object
    120     * @return array of module names following 'exports to'
    121     * @since 6.10.0
    122     */
    123    public String[] getToModuleNames(final ConstantPool constantPool) {
    124        final String[] toModuleNames = new String[exportsToCount];
    125        for (int i = 0; i < exportsToCount; i++) {
    126            toModuleNames[i] = getToModuleNameAtIndex(constantPool, exportsToIndex[i]);
    127        }
    128        return toModuleNames;
    129    }
    130
    131    /**
    132     * @return String representation
    133     */
    134    @Override
    135    public String toString() {
    136        return "exports(" + exportsIndex + ", " + exportsFlags + ", " + exportsToCount + ", ...)";
    137    }
    138
    139    /**
    140     * @return Resolved string representation
    141     */
    142    public String toString(final ConstantPool constantPool) {
    143        final StringBuilder buf = new StringBuilder();
    144        final String packageName = getPackageName(constantPool);
    145        buf.append(packageName);
    146        buf.append(", ").append(String.format("%04x", exportsFlags));
    147        buf.append(", to(").append(exportsToCount).append("):\n");
    148        for (final int index : exportsToIndex) {
    149            final String moduleName = getToModuleNameAtIndex(constantPool, index);
    150            buf.append("      ").append(moduleName).append("\n");
    151        }
    152        return buf.substring(0, buf.length() - 1); // remove the last newline
    153    }
    154}