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; 022 023/** 024 * JSR - Jump to subroutine 025 * 026 */ 027public class JSR extends JsrInstruction implements VariableLengthInstruction { 028 029 /** 030 * Empty constructor needed for Instruction.readInstruction. 031 * Not to be used otherwise. 032 */ 033 JSR() { 034 } 035 036 037 public JSR(final InstructionHandle target) { 038 super(org.apache.bcel.Const.JSR, target); 039 } 040 041 042 /** 043 * Dump instruction as byte code to stream out. 044 * @param out Output stream 045 */ 046 @Override 047 public void dump( final DataOutputStream out ) throws IOException { 048 super.setIndex(getTargetOffset()); 049 if (super.getOpcode() == org.apache.bcel.Const.JSR) { 050 super.dump(out); 051 } else { // JSR_W 052 super.setIndex(getTargetOffset()); 053 out.writeByte(super.getOpcode()); 054 out.writeInt(super.getIndex()); 055 } 056 } 057 058 059 @Override 060 protected int updatePosition( final int offset, final int max_offset ) { 061 final int i = getTargetOffset(); // Depending on old position value 062 setPosition(getPosition() + offset); // Position may be shifted by preceding expansions 063 if (Math.abs(i) >= (Short.MAX_VALUE - max_offset)) { // to large for short (estimate) 064 super.setOpcode(org.apache.bcel.Const.JSR_W); 065 final short old_length = (short) super.getLength(); 066 super.setLength(5); 067 return super.getLength() - old_length; 068 } 069 return 0; 070 } 071 072 073 /** 074 * Call corresponding visitor method(s). The order is: 075 * Call visitor methods of implemented interfaces first, then 076 * call methods according to the class hierarchy in descending order, 077 * i.e., the most specific visitXXX() call comes last. 078 * 079 * @param v Visitor object 080 */ 081 @Override 082 public void accept( final Visitor v ) { 083 v.visitStackProducer(this); 084 v.visitVariableLengthInstruction(this); 085 v.visitBranchInstruction(this); 086 v.visitJsrInstruction(this); 087 v.visitJSR(this); 088 } 089}