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