/* * 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 * * http://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.generic; import java.io.DataOutputStream; import java.io.IOException; import org.apache.bcel.Const; import org.apache.bcel.ExceptionConst; import org.apache.bcel.classfile.ConstantPool; import org.apache.bcel.util.ByteSequence; /** * INVOKEINTERFACE - Invoke interface method *
Stack: ..., objectref, [arg1, [arg2 ...]] -> ...
* * @version $Id$ * @see * * The invokeinterface instruction in The Java Virtual Machine Specification */ public final class INVOKEINTERFACE extends InvokeInstruction { private int nargs; // Number of arguments on stack (number of stack slots), called "count" in vmspec2 /** * Empty constructor needed for Instruction.readInstruction. * Not to be used otherwise. */ INVOKEINTERFACE() { } public INVOKEINTERFACE(final int index, final int nargs) { super(Const.INVOKEINTERFACE, index); super.setLength(5); if (nargs < 1) { throw new ClassGenException("Number of arguments must be > 0 " + nargs); } this.nargs = nargs; } /** * Dump instruction as byte code to stream out. * @param out Output stream */ @Override public void dump( final DataOutputStream out ) throws IOException { out.writeByte(super.getOpcode()); out.writeShort(super.getIndex()); out.writeByte(nargs); out.writeByte(0); } /** * The count argument according to the Java Language Specification, * Second Edition. */ public int getCount() { return nargs; } /** * Read needed data (i.e., index) from file. */ @Override protected void initFromFile( final ByteSequence bytes, final boolean wide ) throws IOException { super.initFromFile(bytes, wide); super.setLength(5); nargs = bytes.readUnsignedByte(); bytes.readByte(); // Skip 0 byte } /** * @return mnemonic for instruction with symbolic references resolved */ @Override public String toString( final ConstantPool cp ) { return super.toString(cp) + " " + nargs; } @Override public int consumeStack( final ConstantPoolGen cpg ) { // nargs is given in byte-code return nargs; // nargs includes this reference } @Override public Class[] getExceptions() { return ExceptionConst.createExceptions(ExceptionConst.EXCS.EXCS_INTERFACE_METHOD_RESOLUTION, ExceptionConst.UNSATISFIED_LINK_ERROR, ExceptionConst.ABSTRACT_METHOD_ERROR, ExceptionConst.ILLEGAL_ACCESS_ERROR, ExceptionConst.INCOMPATIBLE_CLASS_CHANGE_ERROR); } /** * Call corresponding visitor method(s). The order is: * Call visitor methods of implemented interfaces first, then * call methods according to the class hierarchy in descending order, * i.e., the most specific visitXXX() call comes last. * * @param v Visitor object */ @Override public void accept( final Visitor v ) { v.visitExceptionThrower(this); v.visitTypedInstruction(this); v.visitStackConsumer(this); v.visitStackProducer(this); v.visitLoadClass(this); v.visitCPInstruction(this); v.visitFieldOrMethod(this); v.visitInvokeInstruction(this); v.visitINVOKEINTERFACE(this); } }