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
25 import org.apache.bcel.Const;
26
27 /**
28 * This class is derived from the abstract {@link Constant} and represents a reference to a module.
29 *
30 * <p>
31 * Note: Early access Java 9 support- currently subject to change
32 * </p>
33 *
34 * @see Constant
35 * @since 6.1
36 */
37 public final class ConstantModule extends Constant implements ConstantObject {
38
39 private int nameIndex;
40
41 /**
42 * Initialize from another object.
43 *
44 * @param c Source to copy.
45 */
46 public ConstantModule(final ConstantModule c) {
47 this(c.getNameIndex());
48 }
49
50 /**
51 * Initialize instance from file data.
52 *
53 * @param file Input stream.
54 * @throws IOException if an I/O error occurs.
55 */
56 ConstantModule(final DataInput file) throws IOException {
57 this(file.readUnsignedShort());
58 }
59
60 /**
61 * Constructs a ConstantModule.
62 *
63 * @param nameIndex Name index in constant pool. Should refer to a ConstantUtf8.
64 */
65 public ConstantModule(final int nameIndex) {
66 super(Const.CONSTANT_Module);
67 this.nameIndex = nameIndex;
68 }
69
70 /**
71 * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class. I.e.,
72 * the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
73 *
74 * @param v Visitor object.
75 */
76 @Override
77 public void accept(final Visitor v) {
78 v.visitConstantModule(this);
79 }
80
81 /**
82 * Dumps constant module to file stream in binary format.
83 *
84 * @param file Output file stream.
85 * @throws IOException if an I/O error occurs.
86 */
87 @Override
88 public void dump(final DataOutputStream file) throws IOException {
89 file.writeByte(super.getTag());
90 file.writeShort(nameIndex);
91 }
92
93 /**
94 * Gets the dereferenced string.
95 *
96 * @param cp the constant pool.
97 * @return dereferenced string.
98 */
99 public String getBytes(final ConstantPool cp) {
100 return (String) getConstantValue(cp);
101 }
102
103 /**
104 * Gets the String object.
105 *
106 * @param cp the constant pool.
107 * @return String object.
108 */
109 @Override
110 public Object getConstantValue(final ConstantPool cp) {
111 return cp.getConstantUtf8(nameIndex).getBytes();
112 }
113
114 /**
115 * Gets the name index in constant pool of module name.
116 *
117 * @return Name index in constant pool of module name.
118 */
119 public int getNameIndex() {
120 return nameIndex;
121 }
122
123 /**
124 * Sets the name index in the constant pool.
125 *
126 * @param nameIndex the name index in the constant pool of this Constant Module.
127 */
128 public void setNameIndex(final int nameIndex) {
129 this.nameIndex = nameIndex;
130 }
131
132 /**
133 * @return String representation.
134 */
135 @Override
136 public String toString() {
137 return super.toString() + "(nameIndex = " + nameIndex + ")";
138 }
139 }