1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.bcel.classfile;
18
19 import java.io.DataInput;
20 import java.io.DataOutputStream;
21 import java.io.IOException;
22
23 import org.apache.bcel.Const;
24
25 /**
26 * This class is derived from the abstract {@link Constant} and represents a reference to a package.
27 *
28 * <p>
29 * Note: Early access Java 9 support- currently subject to change
30 * </p>
31 *
32 * @see Constant
33 * @since 6.1
34 */
35 public final class ConstantPackage extends Constant implements ConstantObject {
36
37 private int nameIndex;
38
39 /**
40 * Initialize from another object.
41 *
42 * @param c Source to copy.
43 */
44 public ConstantPackage(final ConstantPackage c) {
45 this(c.getNameIndex());
46 }
47
48 /**
49 * Initialize instance from file data.
50 *
51 * @param file Input stream
52 * @throws IOException if an I/O error occurs.
53 */
54 ConstantPackage(final DataInput file) throws IOException {
55 this(file.readUnsignedShort());
56 }
57
58 /**
59 * @param nameIndex Name index in constant pool. Should refer to a ConstantUtf8.
60 */
61 public ConstantPackage(final int nameIndex) {
62 super(Const.CONSTANT_Package);
63 this.nameIndex = nameIndex;
64 }
65
66 /**
67 * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class. I.e.,
68 * the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
69 *
70 * @param v Visitor object
71 */
72 @Override
73 public void accept(final Visitor v) {
74 v.visitConstantPackage(this);
75 }
76
77 /**
78 * Dump constant package to file stream in binary format.
79 *
80 * @param file Output file stream
81 * @throws IOException if an I/O error occurs.
82 */
83 @Override
84 public void dump(final DataOutputStream file) throws IOException {
85 file.writeByte(super.getTag());
86 file.writeShort(nameIndex);
87 }
88
89 /**
90 * @return dereferenced string
91 */
92 public String getBytes(final ConstantPool cp) {
93 return (String) getConstantValue(cp);
94 }
95
96 /**
97 * @return String object
98 */
99 @Override
100 public Object getConstantValue(final ConstantPool cp) {
101 return cp.getConstantUtf8(nameIndex).getBytes();
102 }
103
104 /**
105 * @return Name index in constant pool of package name.
106 */
107 public int getNameIndex() {
108 return nameIndex;
109 }
110
111 /**
112 * @param nameIndex the name index in the constant pool of this Constant Package
113 */
114 public void setNameIndex(final int nameIndex) {
115 this.nameIndex = nameIndex;
116 }
117
118 /**
119 * @return String representation.
120 */
121 @Override
122 public String toString() {
123 return super.toString() + "(nameIndex = " + nameIndex + ")";
124 }
125 }