001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 * 017 */ 018package org.apache.bcel.classfile; 019 020import java.io.DataInput; 021import java.io.IOException; 022 023import org.apache.bcel.Const; 024 025/** 026 * This class is derived from the abstract {@link Constant} and represents a reference to a dynamically computed 027 * constant. 028 * 029 * @see Constant 030 * @see <a href="https://bugs.openjdk.java.net/secure/attachment/74618/constant-dynamic.html"> Change request for JEP 031 * 309</a> 032 * @since 6.3 033 */ 034public final class ConstantDynamic extends ConstantCP { 035 036 /** 037 * Initialize from another object. 038 */ 039 public ConstantDynamic(final ConstantDynamic c) { 040 this(c.getBootstrapMethodAttrIndex(), c.getNameAndTypeIndex()); 041 } 042 043 /** 044 * Initialize instance from file data. 045 * 046 * @param file Input stream 047 * @throws IOException if an I/O error occurs. 048 */ 049 ConstantDynamic(final DataInput file) throws IOException { 050 this(file.readShort(), file.readShort()); 051 } 052 053 public ConstantDynamic(final int bootstrapMethodAttrIndex, final int nameAndTypeIndex) { 054 super(Const.CONSTANT_Dynamic, bootstrapMethodAttrIndex, nameAndTypeIndex); 055 } 056 057 /** 058 * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class. I.e., 059 * the hierarchy of methods, fields, attributes, etc. spawns a tree of objects. 060 * 061 * @param v Visitor object 062 */ 063 @Override 064 public void accept(final Visitor v) { 065 v.visitConstantDynamic(this); 066 } 067 068 /** 069 * @return Reference (index) to bootstrap method this constant refers to. 070 * 071 * Note that this method is a functional duplicate of getClassIndex for use by ConstantInvokeDynamic. 072 * @since 6.0 073 */ 074 public int getBootstrapMethodAttrIndex() { 075 return super.getClassIndex(); // AKA bootstrap_method_attr_index 076 } 077 078 /** 079 * @return String representation 080 */ 081 @Override 082 public String toString() { 083 return super.toString().replace("class_index", "bootstrap_method_attr_index"); 084 } 085}