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.IOException;
21
22 import org.apache.bcel.Const;
23
24 /**
25 * This class is derived from the abstract {@link Constant} and represents a reference to a dynamically computed
26 * constant.
27 *
28 * @see Constant
29 * @see <a href="https://bugs.openjdk.java.net/secure/attachment/74618/constant-dynamic.html"> Change request for JEP
30 * 309</a>
31 * @since 6.3
32 */
33 public final class ConstantDynamic extends ConstantCP {
34
35 /**
36 * Initialize from another object.
37 *
38 * @param c Source to copy.
39 */
40 public ConstantDynamic(final ConstantDynamic c) {
41 this(c.getBootstrapMethodAttrIndex(), c.getNameAndTypeIndex());
42 }
43
44 /**
45 * Initialize instance from file data.
46 *
47 * @param file Input stream
48 * @throws IOException if an I/O error occurs.
49 */
50 ConstantDynamic(final DataInput file) throws IOException {
51 this(file.readShort(), file.readShort());
52 }
53
54 public ConstantDynamic(final int bootstrapMethodAttrIndex, final int nameAndTypeIndex) {
55 super(Const.CONSTANT_Dynamic, bootstrapMethodAttrIndex, nameAndTypeIndex);
56 }
57
58 /**
59 * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class. I.e.,
60 * the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
61 *
62 * @param v Visitor object
63 */
64 @Override
65 public void accept(final Visitor v) {
66 v.visitConstantDynamic(this);
67 }
68
69 /**
70 * @return Reference (index) to bootstrap method this constant refers to.
71 *
72 * Note that this method is a functional duplicate of getClassIndex for use by ConstantInvokeDynamic.
73 * @since 6.0
74 */
75 public int getBootstrapMethodAttrIndex() {
76 return super.getClassIndex(); // AKA bootstrap_method_attr_index
77 }
78
79 /**
80 * @return String representation
81 */
82 @Override
83 public String toString() {
84 return super.toString().replace("class_index", "bootstrap_method_attr_index");
85 }
86 }