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 nameIndex Index in constant pool
042     * @param length Content length in bytes
043     * @param input Input stream
044     * @param constantPool Array of constants
045     * @throws IOException if an I/O error occurs.
046     */
047    ModulePackages(final int nameIndex, final int length, final DataInput input, final ConstantPool constantPool) throws IOException {
048        this(nameIndex, length, (int[]) null, constantPool);
049        final int packageCount = input.readUnsignedShort();
050        packageIndexTable = new int[packageCount];
051        for (int i = 0; i < packageCount; 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 = packageIndexTable.clone();
094        }
095        c.setConstantPool(constantPool);
096        return c;
097    }
098
099    /**
100     * Dump ModulePackages attribute to file stream in binary format.
101     *
102     * @param file Output file stream
103     * @throws IOException if an I/O error occurs.
104     */
105    @Override
106    public void dump(final DataOutputStream file) throws IOException {
107        super.dump(file);
108        file.writeShort(packageIndexTable.length);
109        for (final int index : packageIndexTable) {
110            file.writeShort(index);
111        }
112    }
113
114    /**
115     * @return Length of package table.
116     */
117    public int getNumberOfPackages() {
118        return packageIndexTable == null ? 0 : packageIndexTable.length;
119    }
120
121    /**
122     * @return array of indices into constant pool of package names.
123     */
124    public int[] getPackageIndexTable() {
125        return packageIndexTable;
126    }
127
128    /**
129     * @return string array of package names
130     */
131    public String[] getPackageNames() {
132        final String[] names = new String[packageIndexTable.length];
133        Arrays.setAll(names, i -> Utility.pathToPackage(super.getConstantPool().getConstantString(packageIndexTable[i], Const.CONSTANT_Package)));
134        return names;
135    }
136
137    /**
138     * @param packageIndexTable the list of package indexes Also redefines number_of_packages according to table length.
139     */
140    public void setPackageIndexTable(final int[] packageIndexTable) {
141        this.packageIndexTable = packageIndexTable != null ? packageIndexTable : ArrayUtils.EMPTY_INT_ARRAY;
142    }
143
144    /**
145     * @return String representation, i.e., a list of packages.
146     */
147    @Override
148    public String toString() {
149        final StringBuilder buf = new StringBuilder();
150        buf.append("ModulePackages(");
151        buf.append(packageIndexTable.length);
152        buf.append("):\n");
153        for (final int index : packageIndexTable) {
154            final String packageName = super.getConstantPool().getConstantString(index, Const.CONSTANT_Package);
155            buf.append("  ").append(Utility.compactClassName(packageName, false)).append("\n");
156        }
157        return buf.substring(0, buf.length() - 1); // remove the last newline
158    }
159}