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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *   https://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing,
13   * software distributed under the License is distributed on an
14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   * KIND, either express or implied.  See the License for the
16   * specific language governing permissions and limitations
17   * under the License.
18   */
19  package org.apache.bcel.classfile;
20  
21  import java.io.DataInput;
22  import java.io.DataOutputStream;
23  import java.io.IOException;
24  import java.util.Arrays;
25  import java.util.Iterator;
26  import java.util.stream.Stream;
27  
28  import org.apache.bcel.Const;
29  import org.apache.bcel.util.Args;
30  
31  /**
32   * This class is derived from <em>Attribute</em> and denotes that this class is an Inner class of another. to the source
33   * file of this class. It is instantiated from the <em>Attribute.readAttribute()</em> method.
34   *
35   * @see Attribute
36   */
37  public final class InnerClasses extends Attribute implements Iterable<InnerClass> {
38  
39      /**
40       * Empty array.
41       */
42      private static final InnerClass[] EMPTY_ARRAY = {};
43  
44      private InnerClass[] innerClasses;
45  
46      /**
47       * Initialize from another object. Note that both objects use the same references (shallow copy). Use clone() for a
48       * physical copy.
49       *
50       * @param c Source to copy.
51       */
52      public InnerClasses(final InnerClasses c) {
53          this(c.getNameIndex(), c.getLength(), c.getInnerClasses(), c.getConstantPool());
54      }
55  
56      /**
57       * Constructs object from input stream.
58       *
59       * @param nameIndex Index in constant pool to CONSTANT_Utf8
60       * @param length Content length in bytes
61       * @param input Input stream
62       * @param constantPool Array of constants
63       * @throws IOException if an I/O error occurs.
64       */
65      InnerClasses(final int nameIndex, final int length, final DataInput input, final ConstantPool constantPool) throws IOException {
66          this(nameIndex, length, (InnerClass[]) null, constantPool);
67          final int classCount = input.readUnsignedShort();
68          innerClasses = new InnerClass[classCount];
69          for (int i = 0; i < classCount; i++) {
70              innerClasses[i] = new InnerClass(input);
71          }
72      }
73  
74      /**
75       * @param nameIndex Index in constant pool to CONSTANT_Utf8
76       * @param length Content length in bytes
77       * @param innerClasses array of inner classes attributes
78       * @param constantPool Array of constants
79       */
80      public InnerClasses(final int nameIndex, final int length, final InnerClass[] innerClasses, final ConstantPool constantPool) {
81          super(Const.ATTR_INNER_CLASSES, nameIndex, length, constantPool);
82          this.innerClasses = innerClasses != null ? innerClasses : EMPTY_ARRAY;
83          Args.requireU2(this.innerClasses.length, "innerClasses.length");
84      }
85  
86      /**
87       * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class.
88       * I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
89       *
90       * @param v Visitor object
91       */
92      @Override
93      public void accept(final Visitor v) {
94          v.visitInnerClasses(this);
95      }
96  
97      /**
98       * @return deep copy of this attribute
99       */
100     @Override
101     public Attribute copy(final ConstantPool constantPool) {
102         // TODO this could be recoded to use a lower level constructor after creating a copy of the inner classes
103         final InnerClasses c = (InnerClasses) clone();
104         c.innerClasses = new InnerClass[innerClasses.length];
105         Arrays.setAll(c.innerClasses, i -> innerClasses[i].copy());
106         c.setConstantPool(constantPool);
107         return c;
108     }
109 
110     /**
111      * Dump source file attribute to file stream in binary format.
112      *
113      * @param file Output file stream
114      * @throws IOException if an I/O error occurs.
115      */
116     @Override
117     public void dump(final DataOutputStream file) throws IOException {
118         super.dump(file);
119         file.writeShort(innerClasses.length);
120         for (final InnerClass innerClass : innerClasses) {
121             innerClass.dump(file);
122         }
123     }
124 
125     /**
126      * @return array of inner class "records"
127      */
128     public InnerClass[] getInnerClasses() {
129         return innerClasses;
130     }
131 
132     @Override
133     public Iterator<InnerClass> iterator() {
134         return Stream.of(innerClasses).iterator();
135     }
136 
137     /**
138      * @param innerClasses the array of inner classes
139      */
140     public void setInnerClasses(final InnerClass[] innerClasses) {
141         this.innerClasses = innerClasses != null ? innerClasses : EMPTY_ARRAY;
142     }
143 
144     /**
145      * @return String representation.
146      */
147     @Override
148     public String toString() {
149         final StringBuilder buf = new StringBuilder();
150         buf.append("InnerClasses(");
151         buf.append(innerClasses.length);
152         buf.append("):\n");
153         for (final InnerClass innerClass : innerClasses) {
154             buf.append(innerClass.toString(super.getConstantPool())).append("\n");
155         }
156         return buf.substring(0, buf.length() - 1); // remove the last newline
157     }
158 }