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comparison hg4j/src/main/java/org/tmatesoft/hg/util/PathPool.java @ 213:6ec4af642ba8 gradle

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Project uses Gradle for build - actual changes
author Alexander Kitaev <kitaev@gmail.com>
date Tue, 10 May 2011 10:52:53 +0200
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212:edb2e2829352 213:6ec4af642ba8
1 /*
2 * Copyright (c) 2011 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.util;
18
19 import java.lang.ref.SoftReference;
20 import java.util.WeakHashMap;
21
22
23 /**
24 * Produces path from strings and caches result for reuse
25 *
26 * @author Artem Tikhomirov
27 * @author TMate Software Ltd.
28 */
29 public class PathPool implements Path.Source {
30 private final WeakHashMap<String, SoftReference<Path>> cache;
31 private final PathRewrite pathRewrite;
32
33 public PathPool(PathRewrite rewrite) {
34 pathRewrite = rewrite;
35 cache = new WeakHashMap<String, SoftReference<Path>>();
36 }
37
38 public Path path(String p) {
39 p = pathRewrite.rewrite(p);
40 return get(p, true);
41 }
42
43 // pipes path object through cache to reuse instance, if possible
44 public Path path(Path p) {
45 String s = pathRewrite.rewrite(p.toString());
46 Path cached = get(s, false);
47 if (cached == null) {
48 cache.put(s, new SoftReference<Path>(cached = p));
49 }
50 return cached;
51 }
52
53 // XXX what would be parent of an empty path?
54 // Path shall have similar functionality
55 public Path parent(Path path) {
56 if (path.length() == 0) {
57 throw new IllegalArgumentException();
58 }
59 for (int i = path.length() - 2 /*if path represents a dir, trailing char is slash, skip*/; i >= 0; i--) {
60 if (path.charAt(i) == '/') {
61 return get(path.subSequence(0, i+1).toString(), true);
62 }
63 }
64 return get("", true);
65 }
66
67 private Path get(String p, boolean create) {
68 SoftReference<Path> sr = cache.get(p);
69 Path path = sr == null ? null : sr.get();
70 if (path == null) {
71 if (create) {
72 path = Path.create(p);
73 cache.put(p, new SoftReference<Path>(path));
74 } else if (sr != null) {
75 // cached path no longer used, clear cache entry - do not wait for RefQueue to step in
76 cache.remove(p);
77 }
78 }
79 return path;
80 }
81 }