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} 027 * and represents a reference to a dynamically computed constant. 028 * 029 * @see Constant 030 * @see <a href="https://bugs.openjdk.java.net/secure/attachment/74618/constant-dynamic.html"> 031 * Change request for JEP 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 /** 045 * Initialize instance from file data. 046 * 047 * @param file Input stream 048 * @throws IOException 049 */ 050 ConstantDynamic(final DataInput file) throws IOException { 051 this(file.readShort(), file.readShort()); 052 } 053 054 055 public ConstantDynamic(final int bootstrap_method_attr_index, final int name_and_type_index) { 056 super(Const.CONSTANT_Dynamic, bootstrap_method_attr_index, name_and_type_index); 057 } 058 059 060 /** 061 * Called by objects that are traversing the nodes of the tree implicitly 062 * defined by the contents of a Java class. I.e., the hierarchy of methods, 063 * fields, attributes, etc. spawns a tree of objects. 064 * 065 * @param v Visitor object 066 */ 067 @Override 068 public void accept( final Visitor v ) { 069 v.visitConstantDynamic(this); 070 } 071 072 /** 073 * @return Reference (index) to bootstrap method this constant refers to. 074 * 075 * Note that this method is a functional duplicate of getClassIndex 076 * for use by ConstantInvokeDynamic. 077 * @since 6.0 078 */ 079 public int getBootstrapMethodAttrIndex() { 080 return super.getClassIndex(); // AKA bootstrap_method_attr_index 081 } 082 083 /** 084 * @return String representation 085 */ 086 @Override 087 public String toString() { 088 return super.toString().replace("class_index", "bootstrap_method_attr_index"); 089 } 090}