001 /* 002 $Id: AbstractReaderSource.java,v 1.1 2004/04/19 07:29:44 cpoirier Exp $ 003 004 Copyright 2003 (C) James Strachan and Bob Mcwhirter. All Rights Reserved. 005 006 Redistribution and use of this software and associated documentation 007 ("Software"), with or without modification, are permitted provided 008 that the following conditions are met: 009 010 1. Redistributions of source code must retain copyright 011 statements and notices. Redistributions must also contain a 012 copy of this document. 013 014 2. Redistributions in binary form must reproduce the 015 above copyright notice, this list of conditions and the 016 following disclaimer in the documentation and/or other 017 materials provided with the distribution. 018 019 3. The name "groovy" must not be used to endorse or promote 020 products derived from this Software without prior written 021 permission of The Codehaus. For written permission, 022 please contact info@codehaus.org. 023 024 4. Products derived from this Software may not be called "groovy" 025 nor may "groovy" appear in their names without prior written 026 permission of The Codehaus. "groovy" is a registered 027 trademark of The Codehaus. 028 029 5. Due credit should be given to The Codehaus - 030 http://groovy.codehaus.org/ 031 032 THIS SOFTWARE IS PROVIDED BY THE CODEHAUS AND CONTRIBUTORS 033 ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT 034 NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND 035 FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL 036 THE CODEHAUS OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 037 INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 038 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 039 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 040 HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 041 STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 042 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 043 OF THE POSSIBILITY OF SUCH DAMAGE. 044 045 */ 046 047 package org.codehaus.groovy.control.io; 048 049 import java.io.BufferedReader; 050 import java.io.IOException; 051 052 import org.codehaus.groovy.control.CompilerConfiguration; 053 import org.codehaus.groovy.control.Janitor; 054 055 056 /** 057 * For ReaderSources that can choose a parent class, a base that 058 * provides common functionality. 059 * 060 * @author <a href="mailto:cpoirier@dreaming.org">Chris Poirier</a> 061 * 062 * @version $Id: AbstractReaderSource.java,v 1.1 2004/04/19 07:29:44 cpoirier Exp $ 063 */ 064 065 public abstract class AbstractReaderSource implements ReaderSource 066 { 067 protected CompilerConfiguration configuration; // Configuration data 068 069 070 /** 071 * Standard construction stuff. 072 */ 073 074 public AbstractReaderSource( CompilerConfiguration configuration ) 075 { 076 this.configuration = configuration; 077 } 078 079 080 /** 081 * Returns true if the source can be restarted (ie. if getReader() 082 * will return non-null on subsequent calls. 083 */ 084 085 public boolean canReopenSource() 086 { 087 return true; 088 } 089 090 091 092 //--------------------------------------------------------------------------- 093 // LINE SUPPLY 094 095 096 private BufferedReader lineSource = null; // If set, a reader on the current source file 097 private String line = null; // The last line read from the current source file 098 private int number = 0; // The last line number read 099 100 101 /** 102 * Returns a line from the source, or null, if unavailable. If 103 * you supply a Janitor, resources will be cached. 104 */ 105 106 public String getLine( int lineNumber, Janitor janitor ) 107 { 108 // 109 // If the source is already open and is passed the line we 110 // want, close it. 111 112 if( lineSource != null && number > lineNumber ) 113 { 114 cleanup(); 115 } 116 117 118 // 119 // If the line source is closed, try to open it. 120 121 if( lineSource == null ) 122 { 123 try { lineSource = new BufferedReader( getReader() ); } catch( Exception e ) {} 124 number = 0; 125 } 126 127 128 // 129 // Read until the appropriate line number. 130 131 if( lineSource != null ) 132 { 133 while( number < lineNumber ) 134 { 135 try 136 { 137 line = lineSource.readLine(); 138 number++; 139 } 140 catch( IOException e ) 141 { 142 cleanup(); 143 } 144 } 145 146 if( janitor == null ) 147 { 148 cleanup(); 149 } 150 else 151 { 152 janitor.register( this ); 153 } 154 } 155 156 return line; 157 } 158 159 160 161 /** 162 * Cleans up any cached resources used by getLine(). 163 */ 164 165 public void cleanup() 166 { 167 if( lineSource != null ) 168 { 169 try { lineSource.close(); } catch( Exception e ) {} 170 } 171 172 lineSource = null; 173 line = null; 174 number = 0; 175 } 176 177 }