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