1 /* LineReadingIterator
2 *
3 * $Id: LineReadingIterator.java 4650 2006-09-25 18:09:42Z paul_jack $
4 *
5 * Created on Jul 27, 2004
6 *
7 * Copyright (C) 2004 Internet Archive.
8 *
9 * This file is part of the Heritrix web crawler (crawler.archive.org).
10 *
11 * Heritrix is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU Lesser Public License as published by
13 * the Free Software Foundation; either version 2.1 of the License, or
14 * any later version.
15 *
16 * Heritrix is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU Lesser Public License for more details.
20 *
21 * You should have received a copy of the GNU Lesser Public License
22 * along with Heritrix; if not, write to the Free Software
23 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24 */
25 package org.archive.util.iterator;
26
27 import java.io.BufferedReader;
28 import java.io.IOException;
29 import java.util.logging.Logger;
30
31 /***
32 * Utility class providing an Iterator interface over line-oriented
33 * text input, as a thin wrapper over a BufferedReader.
34 *
35 * @author gojomo
36 */
37 public class LineReadingIterator extends LookaheadIterator<String> {
38 private static final Logger logger =
39 Logger.getLogger(LineReadingIterator.class.getName());
40
41 protected BufferedReader reader = null;
42
43 public LineReadingIterator(BufferedReader r) {
44 reader = r;
45 }
46
47 /***
48 * Loads next line into lookahead spot
49 *
50 * @return whether any item was loaded into next field
51 */
52 protected boolean lookahead() {
53 try {
54 next = this.reader.readLine();
55 if(next == null) {
56 // TODO: make this close-on-exhaust optional?
57 reader.close();
58 }
59 return (next!=null);
60 } catch (IOException e) {
61 logger.warning(e.toString());
62 return false;
63 }
64 }
65 }