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 * 017 */ 018package org.apache.bcel.generic; 019 020import java.io.DataOutputStream; 021import java.io.IOException; 022 023import org.apache.bcel.Const; 024import org.apache.bcel.ExceptionConst; 025import org.apache.bcel.classfile.ConstantPool; 026import org.apache.bcel.util.ByteSequence; 027 028/** 029 * INVOKEINTERFACE - Invoke interface method 030 * 031 * <PRE> 032 * Stack: ..., objectref, [arg1, [arg2 ...]] -> ... 033 * </PRE> 034 * 035 * @see <a href="https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-6.html#jvms-6.5.invokeinterface"> The 036 * invokeinterface instruction in The Java Virtual Machine Specification</a> 037 */ 038public final class INVOKEINTERFACE extends InvokeInstruction { 039 040 private int nargs; // Number of arguments on stack (number of stack slots), called "count" in vmspec2 041 042 /** 043 * Empty constructor needed for Instruction.readInstruction. Not to be used otherwise. 044 */ 045 INVOKEINTERFACE() { 046 } 047 048 public INVOKEINTERFACE(final int index, final int nargs) { 049 super(Const.INVOKEINTERFACE, index); 050 super.setLength(5); 051 if (nargs < 1) { 052 throw new ClassGenException("Number of arguments must be > 0 " + nargs); 053 } 054 this.nargs = nargs; 055 } 056 057 /** 058 * Call corresponding visitor method(s). The order is: Call visitor methods of implemented interfaces first, then call 059 * methods according to the class hierarchy in descending order, i.e., the most specific visitXXX() call comes last. 060 * 061 * @param v Visitor object 062 */ 063 @Override 064 public void accept(final Visitor v) { 065 v.visitExceptionThrower(this); 066 v.visitTypedInstruction(this); 067 v.visitStackConsumer(this); 068 v.visitStackProducer(this); 069 v.visitLoadClass(this); 070 v.visitCPInstruction(this); 071 v.visitFieldOrMethod(this); 072 v.visitInvokeInstruction(this); 073 v.visitINVOKEINTERFACE(this); 074 } 075 076 @Override 077 public int consumeStack(final ConstantPoolGen cpg) { // nargs is given in byte-code 078 return nargs; // nargs includes this reference 079 } 080 081 /** 082 * Dump instruction as byte code to stream out. 083 * 084 * @param out Output stream 085 */ 086 @Override 087 public void dump(final DataOutputStream out) throws IOException { 088 out.writeByte(super.getOpcode()); 089 out.writeShort(super.getIndex()); 090 out.writeByte(nargs); 091 out.writeByte(0); 092 } 093 094 /** 095 * The <B>count</B> argument according to the Java Language Specification, Second Edition. 096 */ 097 public int getCount() { 098 return nargs; 099 } 100 101 @Override 102 public Class<?>[] getExceptions() { 103 return ExceptionConst.createExceptions(ExceptionConst.EXCS.EXCS_INTERFACE_METHOD_RESOLUTION, ExceptionConst.UNSATISFIED_LINK_ERROR, 104 ExceptionConst.ABSTRACT_METHOD_ERROR, ExceptionConst.ILLEGAL_ACCESS_ERROR, ExceptionConst.INCOMPATIBLE_CLASS_CHANGE_ERROR); 105 } 106 107 /** 108 * Read needed data (i.e., index) from file. 109 */ 110 @Override 111 protected void initFromFile(final ByteSequence bytes, final boolean wide) throws IOException { 112 super.initFromFile(bytes, wide); 113 super.setLength(5); 114 nargs = bytes.readUnsignedByte(); 115 bytes.readByte(); // Skip 0 byte 116 } 117 118 /** 119 * @return mnemonic for instruction with symbolic references resolved 120 */ 121 @Override 122 public String toString(final ConstantPool cp) { 123 return super.toString(cp) + " " + nargs; 124 } 125}