    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;
    024import java.util.Iterator;
    025import java.util.stream.Stream;
    026
    027import org.apache.bcel.Const;
    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_INNER_CLASSE_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    public InnerClasses(final InnerClasses c) {
    049        this(c.getNameIndex(), c.getLength(), c.getInnerClasses(), c.getConstantPool());
    050    }
    051
    052    /**
    053     * Construct object from input stream.
    054     *
    055     * @param name_index Index in constant pool to CONSTANT_Utf8
    056     * @param length Content length in bytes
    057     * @param input Input stream
    058     * @param constant_pool Array of constants
    059     * @throws IOException if an I/O error occurs.
    060     */
    061    InnerClasses(final int name_index, final int length, final DataInput input, final ConstantPool constant_pool) throws IOException {
    062        this(name_index, length, (InnerClass[]) null, constant_pool);
    063        final int number_of_classes = input.readUnsignedShort();
    064        innerClasses = new InnerClass[number_of_classes];
    065        for (int i = 0; i < number_of_classes; i++) {
    066            innerClasses[i] = new InnerClass(input);
    067        }
    068    }
    069
    070    /**
    071     * @param name_index Index in constant pool to CONSTANT_Utf8
    072     * @param length Content length in bytes
    073     * @param innerClasses array of inner classes attributes
    074     * @param constant_pool Array of constants
    075     */
    076    public InnerClasses(final int name_index, final int length, final InnerClass[] innerClasses, final ConstantPool constant_pool) {
    077        super(Const.ATTR_INNER_CLASSES, name_index, length, constant_pool);
    078        this.innerClasses = innerClasses != null ? innerClasses : EMPTY_INNER_CLASSE_ARRAY;
    079    }
    080
    081    /**
    082     * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class.
    083     * I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
    084     *
    085     * @param v Visitor object
    086     */
    087    @Override
    088    public void accept(final Visitor v) {
    089        v.visitInnerClasses(this);
    090    }
    091
    092    /**
    093     * @return deep copy of this attribute
    094     */
    095    @Override
    096    public Attribute copy(final ConstantPool constantPool) {
    097        // TODO this could be recoded to use a lower level constructor after creating a copy of the inner classes
    098        final InnerClasses c = (InnerClasses) clone();
    099        c.innerClasses = new InnerClass[innerClasses.length];
    100        Arrays.setAll(c.innerClasses, i -> innerClasses[i].copy());
    101        c.setConstantPool(constantPool);
    102        return c;
    103    }
    104
    105    /**
    106     * Dump source file attribute to file stream in binary format.
    107     *
    108     * @param file Output file stream
    109     * @throws IOException if an I/O error occurs.
    110     */
    111    @Override
    112    public void dump(final DataOutputStream file) throws IOException {
    113        super.dump(file);
    114        file.writeShort(innerClasses.length);
    115        for (final InnerClass inner_class : innerClasses) {
    116            inner_class.dump(file);
    117        }
    118    }
    119
    120    /**
    121     * @return array of inner class "records"
    122     */
    123    public InnerClass[] getInnerClasses() {
    124        return innerClasses;
    125    }
    126
    127    @Override
    128    public Iterator<InnerClass> iterator() {
    129        return Stream.of(innerClasses).iterator();
    130    }
    131
    132    /**
    133     * @param innerClasses the array of inner classes
    134     */
    135    public void setInnerClasses(final InnerClass[] innerClasses) {
    136        this.innerClasses = innerClasses != null ? innerClasses : EMPTY_INNER_CLASSE_ARRAY;
    137    }
    138
    139    /**
    140     * @return String representation.
    141     */
    142    @Override
    143    public String toString() {
    144        final StringBuilder buf = new StringBuilder();
    145        buf.append("InnerClasses(");
    146        buf.append(innerClasses.length);
    147        buf.append("):\n");
    148        for (final InnerClass inner_class : innerClasses) {
    149            buf.append(inner_class.toString(super.getConstantPool())).append("\n");
    150        }
    151        return buf.substring(0, buf.length() - 1); // remove the last newline
    152    }
    153}