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;
023
024import org.apache.bcel.Const;
025
026/**
027 * This class is derived from <em>Attribute</em> and represents the list of packages that are exported or opened by the Module attribute.
028 * There may be at most one ModulePackages attribute in a ClassFile structure.
029 *
030 * @see     Attribute
031 */
032public final class ModulePackages extends Attribute {
033
034    private int[] package_index_table;
035
036
037    /**
038     * Initialize from another object. Note that both objects use the same
039     * references (shallow copy). Use copy() for a physical copy.
040     */
041    public ModulePackages(final ModulePackages c) {
042        this(c.getNameIndex(), c.getLength(), c.getPackageIndexTable(), c.getConstantPool());
043    }
044
045
046    /**
047     * @param name_index Index in constant pool
048     * @param length Content length in bytes
049     * @param package_index_table Table of indices in constant pool
050     * @param constant_pool Array of constants
051     */
052    public ModulePackages(final int name_index, final int length, final int[] package_index_table,
053            final ConstantPool constant_pool) {
054        super(Const.ATTR_MODULE_PACKAGES, name_index, length, constant_pool);
055        this.package_index_table = package_index_table != null ? package_index_table : new int[0];
056    }
057
058
059    /**
060     * Construct object from input stream.
061     * @param name_index Index in constant pool
062     * @param length Content length in bytes
063     * @param input Input stream
064     * @param constant_pool Array of constants
065     * @throws IOException
066     */
067    ModulePackages(final int name_index, final int length, final DataInput input, final ConstantPool constant_pool) throws IOException {
068        this(name_index, length, (int[]) null, constant_pool);
069        final int number_of_packages = input.readUnsignedShort();
070        package_index_table = new int[number_of_packages];
071        for (int i = 0; i < number_of_packages; i++) {
072            package_index_table[i] = input.readUnsignedShort();
073        }
074    }
075
076
077    /**
078     * Called by objects that are traversing the nodes of the tree implicitely
079     * defined by the contents of a Java class. I.e., the hierarchy of methods,
080     * fields, attributes, etc. spawns a tree of objects.
081     *
082     * @param v Visitor object
083     */
084    @Override
085    public void accept( final Visitor v ) {
086        v.visitModulePackages(this);
087    }
088
089
090    /**
091     * Dump ModulePackages attribute to file stream in binary format.
092     *
093     * @param file Output file stream
094     * @throws IOException
095     */
096    @Override
097    public void dump( final DataOutputStream file ) throws IOException {
098        super.dump(file);
099        file.writeShort(package_index_table.length);
100        for (final int index : package_index_table) {
101            file.writeShort(index);
102        }
103    }
104
105
106    /**
107     * @return array of indices into constant pool of package names.
108     */
109    public int[] getPackageIndexTable() {
110        return package_index_table;
111    }
112
113
114    /**
115     * @return Length of package table.
116     */
117    public int getNumberOfPackages() {
118        return package_index_table == null ? 0 : package_index_table.length;
119    }
120
121
122    /**
123     * @return string array of package names
124     */
125    public String[] getPackageNames() {
126        final String[] names = new String[package_index_table.length];
127        for (int i = 0; i < package_index_table.length; i++) {
128            names[i] = super.getConstantPool().getConstantString(package_index_table[i],
129                    Const.CONSTANT_Package).replace('/', '.');
130        }
131        return names;
132    }
133
134
135    /**
136     * @param package_index_table the list of package indexes
137     * Also redefines number_of_packages according to table length.
138     */
139    public void setPackageIndexTable( final int[] package_index_table ) {
140        this.package_index_table = package_index_table != null ? package_index_table : new int[0];
141    }
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(package_index_table.length);
152        buf.append("):\n");
153        for (final int index : package_index_table) {
154            final String package_name = super.getConstantPool().getConstantString(index, Const.CONSTANT_Package);
155            buf.append("  ").append(Utility.compactClassName(package_name, false)).append("\n");
156        }
157        return buf.substring(0, buf.length()-1); // remove the last newline
158    }
159
160
161    /**
162     * @return deep copy of this attribute
163     */
164    @Override
165    public Attribute copy( final ConstantPool _constant_pool ) {
166        final ModulePackages c = (ModulePackages) clone();
167        if (package_index_table != null) {
168            c.package_index_table = new int[package_index_table.length];
169            System.arraycopy(package_index_table, 0, c.package_index_table, 0,
170                    package_index_table.length);
171        }
172        c.setConstantPool(_constant_pool);
173        return c;
174    }
175}