    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 dataInput 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 dataInput, final ConstantPool constantPool) throws IOException {
    051        this(nameIndex, length, (int[]) null, constantPool);
    052        packageIndexTable = ClassParser.readU2U2Table(dataInput);
    053    }
    054
    055    /**
    056     * @param nameIndex Index in constant pool.
    057     * @param length Content length in bytes.
    058     * @param packageIndexTable Table of indices in constant pool.
    059     * @param constantPool Array of constants.
    060     */
    061    public ModulePackages(final int nameIndex, final int length, final int[] packageIndexTable, final ConstantPool constantPool) {
    062        super(Const.ATTR_MODULE_PACKAGES, nameIndex, length, constantPool);
    063        this.packageIndexTable = ArrayUtils.nullToEmpty(packageIndexTable);
    064        Args.requireU2(this.packageIndexTable.length, "packageIndexTable.length");
    065    }
    066
    067    /**
    068     * Initialize from another object. Note that both objects use the same references (shallow copy). Use copy() for a
    069     * physical copy.
    070     *
    071     * @param c Source to copy.
    072     */
    073    public ModulePackages(final ModulePackages c) {
    074        this(c.getNameIndex(), c.getLength(), c.getPackageIndexTable(), c.getConstantPool());
    075    }
    076
    077    /**
    078     * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class.
    079     * I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
    080     *
    081     * @param v Visitor object.
    082     */
    083    @Override
    084    public void accept(final Visitor v) {
    085        v.visitModulePackages(this);
    086    }
    087
    088    /**
    089     * @return deep copy of this attribute.
    090     */
    091    @Override
    092    public Attribute copy(final ConstantPool constantPool) {
    093        final ModulePackages c = (ModulePackages) clone();
    094        if (packageIndexTable != null) {
    095            c.packageIndexTable = packageIndexTable.clone();
    096        }
    097        c.setConstantPool(constantPool);
    098        return c;
    099    }
    100
    101    /**
    102     * Dumps ModulePackages attribute to file stream in binary format.
    103     *
    104     * @param file Output file stream.
    105     * @throws IOException if an I/O error occurs.
    106     */
    107    @Override
    108    public void dump(final DataOutputStream file) throws IOException {
    109        super.dump(file);
    110        file.writeShort(packageIndexTable.length);
    111        for (final int index : packageIndexTable) {
    112            file.writeShort(index);
    113        }
    114    }
    115
    116    /**
    117     * @return Length of package table.
    118     */
    119    public int getNumberOfPackages() {
    120        return packageIndexTable == null ? 0 : packageIndexTable.length;
    121    }
    122
    123    /**
    124     * @return array of indices into constant pool of package names.
    125     */
    126    public int[] getPackageIndexTable() {
    127        return packageIndexTable;
    128    }
    129
    130    /**
    131     * @return string array of package names.
    132     */
    133    public String[] getPackageNames() {
    134        final String[] names = new String[packageIndexTable.length];
    135        Arrays.setAll(names, i -> Utility.pathToPackage(super.getConstantPool().getConstantString(packageIndexTable[i], Const.CONSTANT_Package)));
    136        return names;
    137    }
    138
    139    /**
    140     * @param packageIndexTable the list of package indexes Also redefines number_of_packages according to table length.
    141     */
    142    public void setPackageIndexTable(final int[] packageIndexTable) {
    143        this.packageIndexTable = ArrayUtils.nullToEmpty(packageIndexTable);
    144    }
    145
    146    /**
    147     * @return String representation, that is, a list of packages.
    148     */
    149    @Override
    150    public String toString() {
    151        final StringBuilder buf = new StringBuilder();
    152        buf.append("ModulePackages(");
    153        buf.append(packageIndexTable.length);
    154        buf.append("):\n");
    155        for (final int index : packageIndexTable) {
    156            final String packageName = super.getConstantPool().getConstantString(index, Const.CONSTANT_Package);
    157            buf.append("  ").append(Utility.compactClassName(packageName, false)).append("\n");
    158        }
    159        return buf.substring(0, buf.length() - 1); // remove the last newline
    160    }
    161}