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 */
017package org.apache.bcel.classfile;
018
019import java.io.DataInput;
020import java.io.DataOutputStream;
021import java.io.IOException;
022import java.util.Arrays;
023import java.util.Iterator;
024import java.util.stream.Stream;
025
026import org.apache.bcel.Const;
027import org.apache.bcel.util.Args;
028
029/**
030 * This class is derived from <em>Attribute</em> and denotes that this class is an Inner class of another. to the source
031 * file of this class. It is instantiated from the <em>Attribute.readAttribute()</em> method.
032 *
033 * @see Attribute
034 */
035public final class InnerClasses extends Attribute implements Iterable<InnerClass> {
036
037    /**
038     * Empty array.
039     */
040    private static final InnerClass[] EMPTY_ARRAY = {};
041
042    private InnerClass[] innerClasses;
043
044    /**
045     * Initialize from another object. Note that both objects use the same references (shallow copy). Use clone() for a
046     * physical copy.
047     *
048     * @param c Source to copy.
049     */
050    public InnerClasses(final InnerClasses c) {
051        this(c.getNameIndex(), c.getLength(), c.getInnerClasses(), c.getConstantPool());
052    }
053
054    /**
055     * Constructs object from input stream.
056     *
057     * @param nameIndex Index in constant pool to CONSTANT_Utf8
058     * @param length Content length in bytes
059     * @param input Input stream
060     * @param constantPool Array of constants
061     * @throws IOException if an I/O error occurs.
062     */
063    InnerClasses(final int nameIndex, final int length, final DataInput input, final ConstantPool constantPool) throws IOException {
064        this(nameIndex, length, (InnerClass[]) null, constantPool);
065        final int classCount = input.readUnsignedShort();
066        innerClasses = new InnerClass[classCount];
067        for (int i = 0; i < classCount; i++) {
068            innerClasses[i] = new InnerClass(input);
069        }
070    }
071
072    /**
073     * @param nameIndex Index in constant pool to CONSTANT_Utf8
074     * @param length Content length in bytes
075     * @param innerClasses array of inner classes attributes
076     * @param constantPool Array of constants
077     */
078    public InnerClasses(final int nameIndex, final int length, final InnerClass[] innerClasses, final ConstantPool constantPool) {
079        super(Const.ATTR_INNER_CLASSES, nameIndex, length, constantPool);
080        this.innerClasses = innerClasses != null ? innerClasses : EMPTY_ARRAY;
081        Args.requireU2(this.innerClasses.length, "innerClasses.length");
082    }
083
084    /**
085     * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class.
086     * I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
087     *
088     * @param v Visitor object
089     */
090    @Override
091    public void accept(final Visitor v) {
092        v.visitInnerClasses(this);
093    }
094
095    /**
096     * @return deep copy of this attribute
097     */
098    @Override
099    public Attribute copy(final ConstantPool constantPool) {
100        // TODO this could be recoded to use a lower level constructor after creating a copy of the inner classes
101        final InnerClasses c = (InnerClasses) clone();
102        c.innerClasses = new InnerClass[innerClasses.length];
103        Arrays.setAll(c.innerClasses, i -> innerClasses[i].copy());
104        c.setConstantPool(constantPool);
105        return c;
106    }
107
108    /**
109     * Dump source file attribute to file stream in binary format.
110     *
111     * @param file Output file stream
112     * @throws IOException if an I/O error occurs.
113     */
114    @Override
115    public void dump(final DataOutputStream file) throws IOException {
116        super.dump(file);
117        file.writeShort(innerClasses.length);
118        for (final InnerClass innerClass : innerClasses) {
119            innerClass.dump(file);
120        }
121    }
122
123    /**
124     * @return array of inner class "records"
125     */
126    public InnerClass[] getInnerClasses() {
127        return innerClasses;
128    }
129
130    @Override
131    public Iterator<InnerClass> iterator() {
132        return Stream.of(innerClasses).iterator();
133    }
134
135    /**
136     * @param innerClasses the array of inner classes
137     */
138    public void setInnerClasses(final InnerClass[] innerClasses) {
139        this.innerClasses = innerClasses != null ? innerClasses : EMPTY_ARRAY;
140    }
141
142    /**
143     * @return String representation.
144     */
145    @Override
146    public String toString() {
147        final StringBuilder buf = new StringBuilder();
148        buf.append("InnerClasses(");
149        buf.append(innerClasses.length);
150        buf.append("):\n");
151        for (final InnerClass innerClass : innerClasses) {
152            buf.append(innerClass.toString(super.getConstantPool())).append("\n");
153        }
154        return buf.substring(0, buf.length() - 1); // remove the last newline
155    }
156}