    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 */
    017package org.apache.bcel.classfile;
    018
    019import java.io.DataInput;
    020import java.io.IOException;
    021
    022import org.apache.bcel.Const;
    023
    024/**
    025 * This class is derived from the abstract {@link Constant} and represents a reference to a dynamically computed
    026 * constant.
    027 *
    028 * @see Constant
    029 * @see <a href="https://bugs.openjdk.java.net/secure/attachment/74618/constant-dynamic.html"> Change request for JEP
    030 *      309</a>
    031 * @since 6.3
    032 */
    033public final class ConstantDynamic extends ConstantCP {
    034
    035    /**
    036     * Initialize from another object.
    037     *
    038     * @param c Source to copy.
    039     */
    040    public ConstantDynamic(final ConstantDynamic c) {
    041        this(c.getBootstrapMethodAttrIndex(), c.getNameAndTypeIndex());
    042    }
    043
    044    /**
    045     * Initialize instance from file data.
    046     *
    047     * @param file Input stream
    048     * @throws IOException if an I/O error occurs.
    049     */
    050    ConstantDynamic(final DataInput file) throws IOException {
    051        this(file.readShort(), file.readShort());
    052    }
    053
    054    public ConstantDynamic(final int bootstrapMethodAttrIndex, final int nameAndTypeIndex) {
    055        super(Const.CONSTANT_Dynamic, bootstrapMethodAttrIndex, nameAndTypeIndex);
    056    }
    057
    058    /**
    059     * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class. I.e.,
    060     * the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
    061     *
    062     * @param v Visitor object
    063     */
    064    @Override
    065    public void accept(final Visitor v) {
    066        v.visitConstantDynamic(this);
    067    }
    068
    069    /**
    070     * @return Reference (index) to bootstrap method this constant refers to.
    071     *
    072     *         Note that this method is a functional duplicate of getClassIndex for use by ConstantInvokeDynamic.
    073     * @since 6.0
    074     */
    075    public int getBootstrapMethodAttrIndex() {
    076        return super.getClassIndex(); // AKA bootstrap_method_attr_index
    077    }
    078
    079    /**
    080     * @return String representation
    081     */
    082    @Override
    083    public String toString() {
    084        return super.toString().replace("class_index", "bootstrap_method_attr_index");
    085    }
    086}