src/main/java/org/apache/bcel/classfile/ConstantDynamic.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.bcel.classfile;

import java.io.DataInput;
import java.io.IOException;

import org.apache.bcel.Const;

/**
 * This class is derived from the abstract {@link Constant} and represents a reference to a dynamically computed
 * constant.
 *
 * @see Constant
 * @see <a href="https://bugs.openjdk.java.net/secure/attachment/74618/constant-dynamic.html"> Change request for JEP
 *      309</a>
 * @since 6.3
 */
public final class ConstantDynamic extends ConstantCP {

    /**
     * Initialize from another object.
     *
     * @param c Source to copy.
     */
    public ConstantDynamic(final ConstantDynamic c) {
        this(c.getBootstrapMethodAttrIndex(), c.getNameAndTypeIndex());
    }

    /**
     * Initialize instance from file data.
     *
     * @param file Input stream.
     * @throws IOException if an I/O error occurs.
     */
    ConstantDynamic(final DataInput file) throws IOException {
        this(file.readShort(), file.readShort());
    }

    /**
     * Constructs a ConstantDynamic.
     *
     * @param bootstrapMethodAttrIndex Index to the bootstrap method.
     * @param nameAndTypeIndex Index to the name and type.
     */
    public ConstantDynamic(final int bootstrapMethodAttrIndex, final int nameAndTypeIndex) {
        super(Const.CONSTANT_Dynamic, bootstrapMethodAttrIndex, nameAndTypeIndex);
    }

    /**
     * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class. I.e.,
     * the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
     *
     * @param v Visitor object.
     */
    @Override
    public void accept(final Visitor v) {
        v.visitConstantDynamic(this);
    }

    /**
     * Gets the reference (index) to bootstrap method this constant refers to.
     *
     * @return Reference (index) to bootstrap method this constant refers to.
     *
     *         Note that this method is a functional duplicate of getClassIndex for use by ConstantInvokeDynamic.
     * @since 6.0
     */
    public int getBootstrapMethodAttrIndex() {
        return super.getClassIndex(); // AKA bootstrap_method_attr_index
    }

    /**
     * @return String representation.
     */
    @Override
    public String toString() {
        return super.toString().replace("class_index", "bootstrap_method_attr_index");
    }
}