1 /*
2 $Id: AbstractReaderSource.java,v 1.1 2004/04/19 07:29:44 cpoirier Exp $
3
4 Copyright 2003 (C) James Strachan and Bob Mcwhirter. All Rights Reserved.
5
6 Redistribution and use of this software and associated documentation
7 ("Software"), with or without modification, are permitted provided
8 that the following conditions are met:
9
10 1. Redistributions of source code must retain copyright
11 statements and notices. Redistributions must also contain a
12 copy of this document.
13
14 2. Redistributions in binary form must reproduce the
15 above copyright notice, this list of conditions and the
16 following disclaimer in the documentation and/or other
17 materials provided with the distribution.
18
19 3. The name "groovy" must not be used to endorse or promote
20 products derived from this Software without prior written
21 permission of The Codehaus. For written permission,
22 please contact info@codehaus.org.
23
24 4. Products derived from this Software may not be called "groovy"
25 nor may "groovy" appear in their names without prior written
26 permission of The Codehaus. "groovy" is a registered
27 trademark of The Codehaus.
28
29 5. Due credit should be given to The Codehaus -
30 http://groovy.codehaus.org/
31
32 THIS SOFTWARE IS PROVIDED BY THE CODEHAUS AND CONTRIBUTORS
33 ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
34 NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
35 FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
36 THE CODEHAUS OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
37 INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
38 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
39 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
40 HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
41 STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
42 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
43 OF THE POSSIBILITY OF SUCH DAMAGE.
44
45 */
46
47 package org.codehaus.groovy.control.io;
48
49 import java.io.BufferedReader;
50 import java.io.IOException;
51
52 import org.codehaus.groovy.control.CompilerConfiguration;
53 import org.codehaus.groovy.control.Janitor;
54
55
56 /***
57 * For ReaderSources that can choose a parent class, a base that
58 * provides common functionality.
59 *
60 * @author <a href="mailto:cpoirier@dreaming.org">Chris Poirier</a>
61 *
62 * @version $Id: AbstractReaderSource.java,v 1.1 2004/04/19 07:29:44 cpoirier Exp $
63 */
64
65 public abstract class AbstractReaderSource implements ReaderSource
66 {
67 protected CompilerConfiguration configuration; // Configuration data
68
69
70 /***
71 * Standard construction stuff.
72 */
73
74 public AbstractReaderSource( CompilerConfiguration configuration )
75 {
76 this.configuration = configuration;
77 }
78
79
80 /***
81 * Returns true if the source can be restarted (ie. if getReader()
82 * will return non-null on subsequent calls.
83 */
84
85 public boolean canReopenSource()
86 {
87 return true;
88 }
89
90
91
92 //---------------------------------------------------------------------------
93 // LINE SUPPLY
94
95
96 private BufferedReader lineSource = null; // If set, a reader on the current source file
97 private String line = null; // The last line read from the current source file
98 private int number = 0; // The last line number read
99
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 }