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.IOException;
23
24 import org.apache.bcel.Const;
25
26 /**
27 * This class is derived from the abstract {@link Constant} and represents a reference to a dynamically computed
28 * constant.
29 *
30 * @see Constant
31 * @see <a href="https://bugs.openjdk.java.net/secure/attachment/74618/constant-dynamic.html"> Change request for JEP
32 * 309</a>
33 * @since 6.3
34 */
35 public final class ConstantDynamic extends ConstantCP {
36
37 /**
38 * Initialize from another object.
39 *
40 * @param c Source to copy.
41 */
42 public ConstantDynamic(final ConstantDynamic c) {
43 this(c.getBootstrapMethodAttrIndex(), c.getNameAndTypeIndex());
44 }
45
46 /**
47 * Initialize instance from file data.
48 *
49 * @param file Input stream
50 * @throws IOException if an I/O error occurs.
51 */
52 ConstantDynamic(final DataInput file) throws IOException {
53 this(file.readShort(), file.readShort());
54 }
55
56 public ConstantDynamic(final int bootstrapMethodAttrIndex, final int nameAndTypeIndex) {
57 super(Const.CONSTANT_Dynamic, bootstrapMethodAttrIndex, nameAndTypeIndex);
58 }
59
60 /**
61 * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class. I.e.,
62 * the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
63 *
64 * @param v Visitor object
65 */
66 @Override
67 public void accept(final Visitor v) {
68 v.visitConstantDynamic(this);
69 }
70
71 /**
72 * @return Reference (index) to bootstrap method this constant refers to.
73 *
74 * Note that this method is a functional duplicate of getClassIndex for use by ConstantInvokeDynamic.
75 * @since 6.0
76 */
77 public int getBootstrapMethodAttrIndex() {
78 return super.getClassIndex(); // AKA bootstrap_method_attr_index
79 }
80
81 /**
82 * @return String representation
83 */
84 @Override
85 public String toString() {
86 return super.toString().replace("class_index", "bootstrap_method_attr_index");
87 }
88 }