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 */ 017package org.apache.bcel.classfile; 018 019import java.io.DataInput; 020import java.io.DataOutputStream; 021import java.io.IOException; 022 023/** 024 * This class represents a (PC offset, line number) pair, i.e., a line number in the source that corresponds to a 025 * relative address in the byte code. This is used for debugging purposes. 026 * 027 * @see LineNumberTable 028 */ 029public final class LineNumber implements Cloneable, Node { 030 031 /** Program Counter (PC) corresponds to line */ 032 private short startPc; 033 034 /** number in source file */ 035 private short lineNumber; 036 037 /** 038 * Construct object from file stream. 039 * 040 * @param file Input stream 041 * @throws IOException if an I/O Exception occurs in readUnsignedShort 042 */ 043 LineNumber(final DataInput file) throws IOException { 044 this(file.readUnsignedShort(), file.readUnsignedShort()); 045 } 046 047 /** 048 * @param startPc Program Counter (PC) corresponds to 049 * @param lineNumber line number in source file 050 */ 051 public LineNumber(final int startPc, final int lineNumber) { 052 this.startPc = (short) startPc; 053 this.lineNumber = (short) lineNumber; 054 } 055 056 /** 057 * Initialize from another object. 058 * 059 * @param c the object to copy 060 */ 061 public LineNumber(final LineNumber c) { 062 this(c.getStartPC(), c.getLineNumber()); 063 } 064 065 /** 066 * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class. 067 * I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects. 068 * 069 * @param v Visitor object 070 */ 071 @Override 072 public void accept(final Visitor v) { 073 v.visitLineNumber(this); 074 } 075 076 /** 077 * @return deep copy of this object 078 */ 079 public LineNumber copy() { 080 try { 081 return (LineNumber) clone(); 082 } catch (final CloneNotSupportedException e) { 083 // TODO should this throw? 084 } 085 return null; 086 } 087 088 /** 089 * Dump line number/pc pair to file stream in binary format. 090 * 091 * @param file Output file stream 092 * @throws IOException if an I/O Exception occurs in writeShort 093 */ 094 public void dump(final DataOutputStream file) throws IOException { 095 file.writeShort(startPc); 096 file.writeShort(lineNumber); 097 } 098 099 /** 100 * @return Corresponding source line 101 */ 102 public int getLineNumber() { 103 return lineNumber & 0xffff; 104 } 105 106 /** 107 * @return PC in code 108 */ 109 public int getStartPC() { 110 return startPc & 0xffff; 111 } 112 113 /** 114 * @param lineNumber the source line number 115 */ 116 public void setLineNumber(final int lineNumber) { 117 this.lineNumber = (short) lineNumber; 118 } 119 120 /** 121 * @param startPc the pc for this line number 122 */ 123 public void setStartPC(final int startPc) { 124 this.startPc = (short) startPc; 125 } 126 127 /** 128 * @return String representation 129 */ 130 @Override 131 public String toString() { 132 return "LineNumber(" + getStartPC() + ", " + getLineNumber() + ")"; 133 } 134}