1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 * 17 */ 18 package org.apache.bcel.generic; 19 20 import java.io.DataOutputStream; 21 import java.io.IOException; 22 23 import org.apache.bcel.Const; 24 import org.apache.bcel.ExceptionConst; 25 import org.apache.bcel.classfile.ConstantPool; 26 import org.apache.bcel.util.ByteSequence; 27 28 /** 29 * INVOKEINTERFACE - Invoke interface method 30 * <PRE>Stack: ..., objectref, [arg1, [arg2 ...]] -> ...</PRE> 31 * 32 * @version $Id$ 33 * @see 34 * <a href="http://docs.oracle.com/javase/specs/jvms/se8/html/jvms-6.html#jvms-6.5.invokeinterface"> 35 * The invokeinterface instruction in The Java Virtual Machine Specification</a> 36 */ 37 public final class INVOKEINTERFACE extends InvokeInstruction { 38 39 private int nargs; // Number of arguments on stack (number of stack slots), called "count" in vmspec2 40 41 42 /** 43 * Empty constructor needed for Instruction.readInstruction. 44 * Not to be used otherwise. 45 */ INVOKEINTERFACE()46 INVOKEINTERFACE() { 47 } 48 49 INVOKEINTERFACE(final int index, final int nargs)50 public INVOKEINTERFACE(final int index, final int nargs) { 51 super(Const.INVOKEINTERFACE, index); 52 super.setLength(5); 53 if (nargs < 1) { 54 throw new ClassGenException("Number of arguments must be > 0 " + nargs); 55 } 56 this.nargs = nargs; 57 } 58 59 60 /** 61 * Dump instruction as byte code to stream out. 62 * @param out Output stream 63 */ 64 @Override dump( final DataOutputStream out )65 public void dump( final DataOutputStream out ) throws IOException { 66 out.writeByte(super.getOpcode()); 67 out.writeShort(super.getIndex()); 68 out.writeByte(nargs); 69 out.writeByte(0); 70 } 71 72 73 /** 74 * The <B>count</B> argument according to the Java Language Specification, 75 * Second Edition. 76 */ getCount()77 public int getCount() { 78 return nargs; 79 } 80 81 82 /** 83 * Read needed data (i.e., index) from file. 84 */ 85 @Override initFromFile( final ByteSequence bytes, final boolean wide )86 protected void initFromFile( final ByteSequence bytes, final boolean wide ) throws IOException { 87 super.initFromFile(bytes, wide); 88 super.setLength(5); 89 nargs = bytes.readUnsignedByte(); 90 bytes.readByte(); // Skip 0 byte 91 } 92 93 94 /** 95 * @return mnemonic for instruction with symbolic references resolved 96 */ 97 @Override toString( final ConstantPool cp )98 public String toString( final ConstantPool cp ) { 99 return super.toString(cp) + " " + nargs; 100 } 101 102 103 @Override consumeStack( final ConstantPoolGen cpg )104 public int consumeStack( final ConstantPoolGen cpg ) { // nargs is given in byte-code 105 return nargs; // nargs includes this reference 106 } 107 108 109 @Override getExceptions()110 public Class<?>[] getExceptions() { 111 return ExceptionConst.createExceptions(ExceptionConst.EXCS.EXCS_INTERFACE_METHOD_RESOLUTION, 112 ExceptionConst.UNSATISFIED_LINK_ERROR, 113 ExceptionConst.ABSTRACT_METHOD_ERROR, 114 ExceptionConst.ILLEGAL_ACCESS_ERROR, 115 ExceptionConst.INCOMPATIBLE_CLASS_CHANGE_ERROR); 116 } 117 118 119 /** 120 * Call corresponding visitor method(s). The order is: 121 * Call visitor methods of implemented interfaces first, then 122 * call methods according to the class hierarchy in descending order, 123 * i.e., the most specific visitXXX() call comes last. 124 * 125 * @param v Visitor object 126 */ 127 @Override accept( final Visitor v )128 public void accept( final Visitor v ) { 129 v.visitExceptionThrower(this); 130 v.visitTypedInstruction(this); 131 v.visitStackConsumer(this); 132 v.visitStackProducer(this); 133 v.visitLoadClass(this); 134 v.visitCPInstruction(this); 135 v.visitFieldOrMethod(this); 136 v.visitInvokeInstruction(this); 137 v.visitINVOKEINTERFACE(this); 138 } 139 } 140