    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one
    003 * or more contributor license agreements.  See the NOTICE file
    004 * distributed with this work for additional information
    005 * regarding copyright ownership.  The ASF licenses this file
    006 * to you under the Apache License, Version 2.0 (the
    007 * "License"); you may not use this file except in compliance
    008 * with the License.  You may obtain a copy of the License at
    009 *
    010 *   https://www.apache.org/licenses/LICENSE-2.0
    011 *
    012 * Unless required by applicable law or agreed to in writing,
    013 * software distributed under the License is distributed on an
    014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    015 * KIND, either express or implied.  See the License for the
    016 * specific language governing permissions and limitations
    017 * under the License.
    018 */
    019
    020package org.apache.bcel.classfile;
    021
    022import java.io.DataInput;
    023import java.io.DataOutputStream;
    024import java.io.IOException;
    025import java.util.Arrays;
    026
    027import org.apache.bcel.Const;
    028import org.apache.bcel.util.Args;
    029import org.apache.commons.lang3.ArrayUtils;
    030
    031/**
    032 * This class is derived from <em>Attribute</em> and represents the list of packages that are exported or opened by the
    033 * Module attribute. There may be at most one ModulePackages attribute in a ClassFile structure.
    034 *
    035 * @see Attribute
    036 */
    037public final class ModulePackages extends Attribute {
    038
    039    private int[] packageIndexTable;
    040
    041    /**
    042     * Constructs object from input stream.
    043     *
    044     * @param nameIndex Index in constant pool
    045     * @param length Content length in bytes
    046     * @param input Input stream
    047     * @param constantPool Array of constants
    048     * @throws IOException if an I/O error occurs.
    049     */
    050    ModulePackages(final int nameIndex, final int length, final DataInput input, final ConstantPool constantPool) throws IOException {
    051        this(nameIndex, length, (int[]) null, constantPool);
    052        final int packageCount = input.readUnsignedShort();
    053        packageIndexTable = new int[packageCount];
    054        for (int i = 0; i < packageCount; i++) {
    055            packageIndexTable[i] = input.readUnsignedShort();
    056        }
    057    }
    058
    059    /**
    060     * @param nameIndex Index in constant pool
    061     * @param length Content length in bytes
    062     * @param packageIndexTable Table of indices in constant pool
    063     * @param constantPool Array of constants
    064     */
    065    public ModulePackages(final int nameIndex, final int length, final int[] packageIndexTable, final ConstantPool constantPool) {
    066        super(Const.ATTR_MODULE_PACKAGES, nameIndex, length, constantPool);
    067        this.packageIndexTable = ArrayUtils.nullToEmpty(packageIndexTable);
    068        Args.requireU2(this.packageIndexTable.length, "packageIndexTable.length");
    069    }
    070
    071    /**
    072     * Initialize from another object. Note that both objects use the same references (shallow copy). Use copy() for a
    073     * physical copy.
    074     *
    075     * @param c Source to copy.
    076     */
    077    public ModulePackages(final ModulePackages c) {
    078        this(c.getNameIndex(), c.getLength(), c.getPackageIndexTable(), c.getConstantPool());
    079    }
    080
    081    /**
    082     * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class.
    083     * I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
    084     *
    085     * @param v Visitor object
    086     */
    087    @Override
    088    public void accept(final Visitor v) {
    089        v.visitModulePackages(this);
    090    }
    091
    092    /**
    093     * @return deep copy of this attribute
    094     */
    095    @Override
    096    public Attribute copy(final ConstantPool constantPool) {
    097        final ModulePackages c = (ModulePackages) clone();
    098        if (packageIndexTable != null) {
    099            c.packageIndexTable = packageIndexTable.clone();
    100        }
    101        c.setConstantPool(constantPool);
    102        return c;
    103    }
    104
    105    /**
    106     * Dump ModulePackages attribute to file stream in binary format.
    107     *
    108     * @param file Output file stream
    109     * @throws IOException if an I/O error occurs.
    110     */
    111    @Override
    112    public void dump(final DataOutputStream file) throws IOException {
    113        super.dump(file);
    114        file.writeShort(packageIndexTable.length);
    115        for (final int index : packageIndexTable) {
    116            file.writeShort(index);
    117        }
    118    }
    119
    120    /**
    121     * @return Length of package table.
    122     */
    123    public int getNumberOfPackages() {
    124        return packageIndexTable == null ? 0 : packageIndexTable.length;
    125    }
    126
    127    /**
    128     * @return array of indices into constant pool of package names.
    129     */
    130    public int[] getPackageIndexTable() {
    131        return packageIndexTable;
    132    }
    133
    134    /**
    135     * @return string array of package names
    136     */
    137    public String[] getPackageNames() {
    138        final String[] names = new String[packageIndexTable.length];
    139        Arrays.setAll(names, i -> Utility.pathToPackage(super.getConstantPool().getConstantString(packageIndexTable[i], Const.CONSTANT_Package)));
    140        return names;
    141    }
    142
    143    /**
    144     * @param packageIndexTable the list of package indexes Also redefines number_of_packages according to table length.
    145     */
    146    public void setPackageIndexTable(final int[] packageIndexTable) {
    147        this.packageIndexTable = ArrayUtils.nullToEmpty(packageIndexTable);
    148    }
    149
    150    /**
    151     * @return String representation, i.e., a list of packages.
    152     */
    153    @Override
    154    public String toString() {
    155        final StringBuilder buf = new StringBuilder();
    156        buf.append("ModulePackages(");
    157        buf.append(packageIndexTable.length);
    158        buf.append("):\n");
    159        for (final int index : packageIndexTable) {
    160            final String packageName = super.getConstantPool().getConstantString(index, Const.CONSTANT_Package);
    161            buf.append("  ").append(Utility.compactClassName(packageName, false)).append("\n");
    162        }
    163        return buf.substring(0, buf.length() - 1); // remove the last newline
    164    }
    165}