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comparison src/org/tmatesoft/hg/internal/LineReader.java @ 480:f3fab7a20841

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Refactor LineReader utility as stanalone class to facilitate reuse
author Artem Tikhomirov <tikhomirov.artem@gmail.com>
date Tue, 17 Jul 2012 22:14:21 +0200
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children e31e85cf4d4c
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479:59b7c817bc4d 480:f3fab7a20841
1 /*
2 * Copyright (c) 2012 TMate Software Ltd
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; version 2 of the License.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * For information on how to redistribute this software under
14 * the terms of a license other than GNU General Public License
15 * contact TMate Software at support@hg4j.com
16 */
17 package org.tmatesoft.hg.internal;
18
19 import static org.tmatesoft.hg.util.LogFacility.Severity.Warn;
20
21 import java.io.BufferedReader;
22 import java.io.File;
23 import java.io.FileReader;
24 import java.io.IOException;
25 import java.util.Collection;
26
27 import org.tmatesoft.hg.repo.HgInvalidFileException;
28 import org.tmatesoft.hg.repo.ext.MqManager;
29 import org.tmatesoft.hg.util.LogFacility;
30
31 /**
32 * Handy class to read line-based configuration files
33 *
34 * @author Artem Tikhomirov
35 * @author TMate Software Ltd.
36 */
37 public final class LineReader {
38
39 public interface LineConsumer<T> {
40 // boolean begin(File f, T paramObj) throws IOException;
41 boolean consume(String line, T paramObj) throws IOException;
42 // boolean end(File f, T paramObj) throws IOException;
43 }
44
45 public static class SimpleLineCollector implements LineReader.LineConsumer<Collection<String>> {
46
47 public boolean consume(String line, Collection<String> result) throws IOException {
48 result.add(line);
49 return true;
50 }
51 }
52
53 private final File file;
54 private final LogFacility log;
55 private boolean trimLines = true;
56 private boolean skipEmpty = true;
57 private String ignoreThatStarts = null;
58
59 public LineReader(File f, LogFacility logFacility) {
60 file = f;
61 log = logFacility;
62 }
63
64 /**
65 * default: <code>true</code>
66 * <code>false</code> to return line as is
67 */
68 public LineReader trimLines(boolean trim) {
69 trimLines = trim;
70 return this;
71 }
72
73 /**
74 * default: <code>true</code>
75 * <code>false</code> to pass empty lines to consumer
76 */
77 public LineReader skipEmpty(boolean skip) {
78 skipEmpty = skip;
79 return this;
80 }
81
82 /**
83 * default: doesn't skip any line.
84 * set e.g. to "#" or "//" to skip lines that start with such prefix
85 */
86 public LineReader ignoreLineComments(String lineStart) {
87 ignoreThatStarts = lineStart;
88 return this;
89 }
90
91 public <T> void read(LineConsumer<T> consumer, T paramObj) throws HgInvalidFileException {
92 BufferedReader statusFileReader = null;
93 try {
94 // consumer.begin(file, paramObj);
95 statusFileReader = new BufferedReader(new FileReader(file));
96 String line;
97 boolean ok = true;
98 while (ok && (line = statusFileReader.readLine()) != null) {
99 if (trimLines) {
100 line = line.trim();
101 }
102 if (ignoreThatStarts != null && line.startsWith(ignoreThatStarts)) {
103 continue;
104 }
105 if (!skipEmpty || line.length() > 0) {
106 ok = consumer.consume(line, paramObj);
107 }
108 }
109 } catch (IOException ex) {
110 throw new HgInvalidFileException(ex.getMessage(), ex, file);
111 } finally {
112 try {
113 statusFileReader.close();
114 } catch (IOException ex) {
115 log.dump(MqManager.class, Warn, ex, null);
116 }
117 // try {
118 // consumer.end(file, paramObj);
119 // } catch (IOException ex) {
120 // log.warn(MqManager.class, ex, null);
121 // }
122 }
123 }
124 }