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.classfile; 019 020import java.io.DataInput; 021import java.io.DataOutputStream; 022import java.io.IOException; 023 024/** 025 * This class represents a (PC offset, line number) pair, i.e., a line number in the source that corresponds to a 026 * relative address in the byte code. This is used for debugging purposes. 027 * 028 * @see LineNumberTable 029 */ 030public final class LineNumber implements Cloneable, Node { 031 032 /** Program Counter (PC) corresponds to line */ 033 private short startPc; 034 035 /** number in source file */ 036 private short lineNumber; 037 038 /** 039 * Construct object from file stream. 040 * 041 * @param file Input stream 042 * @throws IOException if an I/O Exception occurs in readUnsignedShort 043 */ 044 LineNumber(final DataInput file) throws IOException { 045 this(file.readUnsignedShort(), file.readUnsignedShort()); 046 } 047 048 /** 049 * @param startPc Program Counter (PC) corresponds to 050 * @param lineNumber line number in source file 051 */ 052 public LineNumber(final int startPc, final int lineNumber) { 053 this.startPc = (short) startPc; 054 this.lineNumber = (short) lineNumber; 055 } 056 057 /** 058 * Initialize from another object. 059 * 060 * @param c the object to copy 061 */ 062 public LineNumber(final LineNumber c) { 063 this(c.getStartPC(), c.getLineNumber()); 064 } 065 066 /** 067 * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class. 068 * I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects. 069 * 070 * @param v Visitor object 071 */ 072 @Override 073 public void accept(final Visitor v) { 074 v.visitLineNumber(this); 075 } 076 077 /** 078 * @return deep copy of this object 079 */ 080 public LineNumber copy() { 081 try { 082 return (LineNumber) clone(); 083 } catch (final CloneNotSupportedException e) { 084 // TODO should this throw? 085 } 086 return null; 087 } 088 089 /** 090 * Dump line number/pc pair to file stream in binary format. 091 * 092 * @param file Output file stream 093 * @throws IOException if an I/O Exception occurs in writeShort 094 */ 095 public void dump(final DataOutputStream file) throws IOException { 096 file.writeShort(startPc); 097 file.writeShort(lineNumber); 098 } 099 100 /** 101 * @return Corresponding source line 102 */ 103 public int getLineNumber() { 104 return lineNumber & 0xffff; 105 } 106 107 /** 108 * @return PC in code 109 */ 110 public int getStartPC() { 111 return startPc & 0xffff; 112 } 113 114 /** 115 * @param lineNumber the source line number 116 */ 117 public void setLineNumber(final int lineNumber) { 118 this.lineNumber = (short) lineNumber; 119 } 120 121 /** 122 * @param startPc the pc for this line number 123 */ 124 public void setStartPC(final int startPc) { 125 this.startPc = (short) startPc; 126 } 127 128 /** 129 * @return String representation 130 */ 131 @Override 132 public String toString() { 133 return "LineNumber(" + getStartPC() + ", " + getLineNumber() + ")"; 134 } 135}