    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.generic;
    018
    019import java.io.DataOutputStream;
    020import java.io.IOException;
    021
    022import org.apache.bcel.Const;
    023import org.apache.bcel.ExceptionConst;
    024import org.apache.bcel.classfile.ConstantInvokeDynamic;
    025import org.apache.bcel.classfile.ConstantNameAndType;
    026import org.apache.bcel.classfile.ConstantPool;
    027import org.apache.bcel.util.ByteSequence;
    028
    029/**
    030 * Class for INVOKEDYNAMIC. Not an instance of InvokeInstruction, since that class expects to be able to get the class
    031 * of the method. Ignores the bootstrap mechanism entirely.
    032 *
    033 * @see <a href="https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-6.html#jvms-6.5.invokedynamic"> The
    034 *      invokedynamic instruction in The Java Virtual Machine Specification</a>
    035 * @since 6.0
    036 */
    037public class INVOKEDYNAMIC extends InvokeInstruction {
    038
    039    /**
    040     * Empty constructor needed for Instruction.readInstruction. Not to be used otherwise.
    041     */
    042    INVOKEDYNAMIC() {
    043    }
    044
    045    public INVOKEDYNAMIC(final int index) {
    046        super(Const.INVOKEDYNAMIC, index);
    047    }
    048
    049    /**
    050     * Call corresponding visitor method(s). The order is: Call visitor methods of implemented interfaces first, then call
    051     * methods according to the class hierarchy in descending order, i.e., the most specific visitXXX() call comes last.
    052     *
    053     * @param v Visitor object
    054     */
    055    @Override
    056    public void accept(final Visitor v) {
    057        v.visitExceptionThrower(this);
    058        v.visitTypedInstruction(this);
    059        v.visitStackConsumer(this);
    060        v.visitStackProducer(this);
    061        v.visitLoadClass(this);
    062        v.visitCPInstruction(this);
    063        v.visitFieldOrMethod(this);
    064        v.visitInvokeInstruction(this);
    065        v.visitINVOKEDYNAMIC(this);
    066    }
    067
    068    /**
    069     * Dump instruction as byte code to stream out.
    070     *
    071     * @param out Output stream
    072     */
    073    @Override
    074    public void dump(final DataOutputStream out) throws IOException {
    075        out.writeByte(super.getOpcode());
    076        out.writeShort(super.getIndex());
    077        out.writeByte(0);
    078        out.writeByte(0);
    079    }
    080
    081    /**
    082     * Override the parent method because our class name is held elsewhere.
    083     *
    084     * Note: Contrary to this method's name it does not return the class name of the invoke target; rather it returns the
    085     * name of the method that will be used to invoke the Lambda method generated by this invoke dynamic instruction.
    086     */
    087    @Override
    088    public String getClassName(final ConstantPoolGen cpg) {
    089        final ConstantPool cp = cpg.getConstantPool();
    090        final ConstantInvokeDynamic cid = cp.getConstant(super.getIndex(), Const.CONSTANT_InvokeDynamic, ConstantInvokeDynamic.class);
    091        return cp.getConstant(cid.getNameAndTypeIndex(), ConstantNameAndType.class).getName(cp);
    092    }
    093
    094    @Override
    095    public Class<?>[] getExceptions() {
    096        return ExceptionConst.createExceptions(ExceptionConst.EXCS.EXCS_INTERFACE_METHOD_RESOLUTION, ExceptionConst.UNSATISFIED_LINK_ERROR,
    097            ExceptionConst.ABSTRACT_METHOD_ERROR, ExceptionConst.ILLEGAL_ACCESS_ERROR, ExceptionConst.INCOMPATIBLE_CLASS_CHANGE_ERROR);
    098    }
    099
    100    /**
    101     * Since InvokeDynamic doesn't refer to a reference type, just return java.lang.Object, as that is the only type we can
    102     * say for sure the reference will be.
    103     *
    104     * @param cpg the ConstantPoolGen used to create the instruction
    105     * @return an ObjectType for java.lang.Object
    106     * @since 6.1
    107     */
    108    @Override
    109    public ReferenceType getReferenceType(final ConstantPoolGen cpg) {
    110        return new ObjectType(Object.class.getName());
    111    }
    112
    113    /**
    114     * Read needed data (i.e., index) from file.
    115     */
    116    @Override
    117    protected void initFromFile(final ByteSequence bytes, final boolean wide) throws IOException {
    118        super.initFromFile(bytes, wide);
    119        super.setLength(5);
    120        bytes.readByte(); // Skip 0 byte
    121        bytes.readByte(); // Skip 0 byte
    122    }
    123
    124}