    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one
    003 * or more contributor license agreements.  See the NOTICE file
    004 * distributed with this work for additional information
    005 * regarding copyright ownership.  The ASF licenses this file
    006 * to you under the Apache License, Version 2.0 (the
    007 * "License"); you may not use this file except in compliance
    008 * with the License.  You may obtain a copy of the License at
    009 *
    010 *   https://www.apache.org/licenses/LICENSE-2.0
    011 *
    012 * Unless required by applicable law or agreed to in writing,
    013 * software distributed under the License is distributed on an
    014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    015 * KIND, either express or implied.  See the License for the
    016 * specific language governing permissions and limitations
    017 * under the License.
    018 */
    019package org.apache.bcel.generic;
    020
    021import java.io.DataOutputStream;
    022import java.io.IOException;
    023
    024import org.apache.bcel.Const;
    025import org.apache.bcel.ExceptionConst;
    026import org.apache.bcel.classfile.ConstantInvokeDynamic;
    027import org.apache.bcel.classfile.ConstantNameAndType;
    028import org.apache.bcel.classfile.ConstantPool;
    029import org.apache.bcel.util.ByteSequence;
    030
    031/**
    032 * Class for INVOKEDYNAMIC. Not an instance of InvokeInstruction, since that class expects to be able to get the class
    033 * of the method. Ignores the bootstrap mechanism entirely.
    034 *
    035 * @see <a href="https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-6.html#jvms-6.5.invokedynamic"> The
    036 *      invokedynamic instruction in The Java Virtual Machine Specification</a>
    037 * @since 6.0
    038 */
    039public class INVOKEDYNAMIC extends InvokeInstruction {
    040
    041    /**
    042     * Empty constructor needed for Instruction.readInstruction. Not to be used otherwise.
    043     */
    044    INVOKEDYNAMIC() {
    045    }
    046
    047    public INVOKEDYNAMIC(final int index) {
    048        super(Const.INVOKEDYNAMIC, index);
    049    }
    050
    051    /**
    052     * Call corresponding visitor method(s). The order is: Call visitor methods of implemented interfaces first, then call
    053     * methods according to the class hierarchy in descending order, that is, the most specific visitXXX() call comes last.
    054     *
    055     * @param v Visitor object.
    056     */
    057    @Override
    058    public void accept(final Visitor v) {
    059        v.visitExceptionThrower(this);
    060        v.visitTypedInstruction(this);
    061        v.visitStackConsumer(this);
    062        v.visitStackProducer(this);
    063        v.visitLoadClass(this);
    064        v.visitCPInstruction(this);
    065        v.visitFieldOrMethod(this);
    066        v.visitInvokeInstruction(this);
    067        v.visitINVOKEDYNAMIC(this);
    068    }
    069
    070    /**
    071     * Dumps instruction as byte code to stream out.
    072     *
    073     * @param out Output stream.
    074     */
    075    @Override
    076    public void dump(final DataOutputStream out) throws IOException {
    077        out.writeByte(super.getOpcode());
    078        out.writeShort(super.getIndex());
    079        out.writeByte(0);
    080        out.writeByte(0);
    081    }
    082
    083    /**
    084     * Override the parent method because our class name is held elsewhere.
    085     *
    086     * Note: Contrary to this method's name it does not return the class name of the invoke target; rather it returns the
    087     * name of the method that will be used to invoke the Lambda method generated by this invoke dynamic instruction.
    088     */
    089    @Override
    090    public String getClassName(final ConstantPoolGen cpg) {
    091        final ConstantPool cp = cpg.getConstantPool();
    092        final ConstantInvokeDynamic cid = cp.getConstant(super.getIndex(), Const.CONSTANT_InvokeDynamic, ConstantInvokeDynamic.class);
    093        return cp.getConstant(cid.getNameAndTypeIndex(), ConstantNameAndType.class).getName(cp);
    094    }
    095
    096    @Override
    097    public Class<?>[] getExceptions() {
    098        return ExceptionConst.createExceptions(ExceptionConst.EXCS.EXCS_INTERFACE_METHOD_RESOLUTION, ExceptionConst.UNSATISFIED_LINK_ERROR,
    099            ExceptionConst.ABSTRACT_METHOD_ERROR, ExceptionConst.ILLEGAL_ACCESS_ERROR, ExceptionConst.INCOMPATIBLE_CLASS_CHANGE_ERROR);
    100    }
    101
    102    /**
    103     * Since InvokeDynamic doesn't refer to a reference type, just return {@link Object}, as that is the only type we can
    104     * say for sure the reference will be.
    105     *
    106     * @param cpg the ConstantPoolGen used to create the instruction.
    107     * @return an ObjectType for {@link Object}.
    108     * @since 6.1
    109     */
    110    @Override
    111    public ReferenceType getReferenceType(final ConstantPoolGen cpg) {
    112        return new ObjectType(Object.class.getName());
    113    }
    114
    115    /**
    116     * Reads needed data (that is, index) from file.
    117     */
    118    @Override
    119    protected void initFromFile(final ByteSequence bytes, final boolean wide) throws IOException {
    120        super.initFromFile(bytes, wide);
    121        super.setLength(5);
    122        bytes.readByte(); // Skip 0 byte
    123        bytes.readByte(); // Skip 0 byte
    124    }
    125
    126}