    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;
    026import org.apache.bcel.util.Args;
    027import org.apache.commons.lang3.ArrayUtils;
    028
    029/**
    030 * This class is derived from <em>Attribute</em> and represents the list of packages that are exported or opened by the
    031 * Module attribute. There may be at most one ModulePackages attribute in a ClassFile structure.
    032 *
    033 * @see Attribute
    034 */
    035public final class ModulePackages extends Attribute {
    036
    037    private int[] packageIndexTable;
    038
    039    /**
    040     * Constructs object from input stream.
    041     *
    042     * @param nameIndex Index in constant pool
    043     * @param length Content length in bytes
    044     * @param input Input stream
    045     * @param constantPool Array of constants
    046     * @throws IOException if an I/O error occurs.
    047     */
    048    ModulePackages(final int nameIndex, final int length, final DataInput input, final ConstantPool constantPool) throws IOException {
    049        this(nameIndex, length, (int[]) null, constantPool);
    050        final int packageCount = input.readUnsignedShort();
    051        packageIndexTable = new int[packageCount];
    052        for (int i = 0; i < packageCount; i++) {
    053            packageIndexTable[i] = input.readUnsignedShort();
    054        }
    055    }
    056
    057    /**
    058     * @param nameIndex Index in constant pool
    059     * @param length Content length in bytes
    060     * @param packageIndexTable Table of indices in constant pool
    061     * @param constantPool Array of constants
    062     */
    063    public ModulePackages(final int nameIndex, final int length, final int[] packageIndexTable, final ConstantPool constantPool) {
    064        super(Const.ATTR_MODULE_PACKAGES, nameIndex, length, constantPool);
    065        this.packageIndexTable = ArrayUtils.nullToEmpty(packageIndexTable);
    066        Args.requireU2(this.packageIndexTable.length, "packageIndexTable.length");
    067    }
    068
    069    /**
    070     * Initialize from another object. Note that both objects use the same references (shallow copy). Use copy() for a
    071     * physical copy.
    072     *
    073     * @param c Source to copy.
    074     */
    075    public ModulePackages(final ModulePackages c) {
    076        this(c.getNameIndex(), c.getLength(), c.getPackageIndexTable(), c.getConstantPool());
    077    }
    078
    079    /**
    080     * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class.
    081     * I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
    082     *
    083     * @param v Visitor object
    084     */
    085    @Override
    086    public void accept(final Visitor v) {
    087        v.visitModulePackages(this);
    088    }
    089
    090    /**
    091     * @return deep copy of this attribute
    092     */
    093    @Override
    094    public Attribute copy(final ConstantPool constantPool) {
    095        final ModulePackages c = (ModulePackages) clone();
    096        if (packageIndexTable != null) {
    097            c.packageIndexTable = packageIndexTable.clone();
    098        }
    099        c.setConstantPool(constantPool);
    100        return c;
    101    }
    102
    103    /**
    104     * Dump ModulePackages attribute to file stream in binary format.
    105     *
    106     * @param file Output file stream
    107     * @throws IOException if an I/O error occurs.
    108     */
    109    @Override
    110    public void dump(final DataOutputStream file) throws IOException {
    111        super.dump(file);
    112        file.writeShort(packageIndexTable.length);
    113        for (final int index : packageIndexTable) {
    114            file.writeShort(index);
    115        }
    116    }
    117
    118    /**
    119     * @return Length of package table.
    120     */
    121    public int getNumberOfPackages() {
    122        return packageIndexTable == null ? 0 : packageIndexTable.length;
    123    }
    124
    125    /**
    126     * @return array of indices into constant pool of package names.
    127     */
    128    public int[] getPackageIndexTable() {
    129        return packageIndexTable;
    130    }
    131
    132    /**
    133     * @return string array of package names
    134     */
    135    public String[] getPackageNames() {
    136        final String[] names = new String[packageIndexTable.length];
    137        Arrays.setAll(names, i -> Utility.pathToPackage(super.getConstantPool().getConstantString(packageIndexTable[i], Const.CONSTANT_Package)));
    138        return names;
    139    }
    140
    141    /**
    142     * @param packageIndexTable the list of package indexes Also redefines number_of_packages according to table length.
    143     */
    144    public void setPackageIndexTable(final int[] packageIndexTable) {
    145        this.packageIndexTable = ArrayUtils.nullToEmpty(packageIndexTable);
    146    }
    147
    148    /**
    149     * @return String representation, i.e., a list of packages.
    150     */
    151    @Override
    152    public String toString() {
    153        final StringBuilder buf = new StringBuilder();
    154        buf.append("ModulePackages(");
    155        buf.append(packageIndexTable.length);
    156        buf.append("):\n");
    157        for (final int index : packageIndexTable) {
    158            final String packageName = super.getConstantPool().getConstantString(index, Const.CONSTANT_Package);
    159            buf.append("  ").append(Utility.compactClassName(packageName, false)).append("\n");
    160        }
    161        return buf.substring(0, buf.length() - 1); // remove the last newline
    162    }
    163}