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comparison servlet/src/digilib/io/DocuDirCache.java @ 339:6d2032b6121d gen2_1

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new directory and cache work
author robcast
date Wed, 17 Nov 2004 18:17:34 +0100
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3:794a9f25f15c 339:6d2032b6121d
1 /*
2 * DocuDirCache.java
3 *
4 * Digital Image Library servlet components
5 *
6 * Copyright (C) 2003 Robert Casties (robcast@mail.berlios.de)
7 *
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License as published by the Free
10 * Software Foundation; either version 2 of the License, or (at your option)
11 * any later version.
12 *
13 * Please read license.txt for the full details. A copy of the GPL may be found
14 * at http://www.gnu.org/copyleft/lgpl.html
15 *
16 * You should have received a copy of the GNU General Public License along with
17 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
18 * Place, Suite 330, Boston, MA 02111-1307 USA
19 *
20 * Created on 03.03.2003
21 */
22
23 package digilib.io;
24
25 import java.io.File;
26 import java.util.HashMap;
27 import java.util.Map;
28
29 import org.apache.log4j.Logger;
30
31 /**
32 * Cache of digilib directories.
33 *
34 * @author casties
35 */
36 public class DocuDirCache {
37
38 /** general logger for this class */
39 protected static Logger logger = Logger.getLogger(DocuDirCache.class);
40
41 /** Map of directories */
42 Map map = null;
43
44 /** number of files in the whole cache (approximate) */
45 long numFiles = 0;
46
47 /** number of cache hits */
48 long hits = 0;
49
50 /** number of cache misses */
51 long misses = 0;
52
53 /** the root directory element */
54 public DigiDirectory rootDir = null;
55
56 /**
57 * Default constructor.
58 */
59 public DocuDirCache() {
60 map = new HashMap();
61 // add root directory
62 rootDir = new DigiDirectory(FileOps.getBaseDirs()[0], "", null);
63 map.put("", rootDir);
64 }
65
66 /**
67 * The number of directories in the cache.
68 *
69 * @return
70 */
71 public int size() {
72 return (map != null) ? map.size() : 0;
73 }
74
75 /**
76 * Add a DocuDirectory to the cache.
77 *
78 * @param newdir
79 */
80 public void put(DigiDirectory newdir) {
81 String s = newdir.getDLPath();
82 Object oldkey = map.put(s, newdir);
83 if (oldkey != null) {
84 logger.warn("Duplicate key in DocuDirCache.put -- overwritten!");
85 }
86 numFiles += newdir.getSize();
87 }
88
89 /**
90 * Add a directory to the cache and check its parents.
91 *
92 * @param newDir
93 */
94 public synchronized void putDir(DigiDirectory newDir) {
95 put(newDir);
96 }
97
98 /**
99 * Returns a DigiDirectory from the cache.
100 *
101 * @param path
102 * @return
103 */
104 public DigiDirectory get(String path) {
105 return (DigiDirectory) map.get(path);
106 }
107
108 /**
109 * Returns the DigiDirectory indicated by the pathname <code>fn</code>.
110 *
111 * If <code>fn</code> is a file then its parent directory is returned.
112 *
113 * @param fn
114 * digilib pathname
115 * @return
116 */
117 public DigiDirectory getDirectory(String pn) {
118 /*
119 * first, assume pn is a directory and look in the cache
120 */
121 DigiDirectory dd = (DigiDirectory) map.get(pn);
122 if (dd != null) {
123 // cache hit
124 hits++;
125 return dd;
126 } else {
127 /*
128 * maybe it's a file? try the parent directory
129 */
130 String dn = FileOps.dlParent(pn);
131 // try it in the cache
132 dd = (DigiDirectory) map.get(dn);
133 if (dd != null) {
134 // cache hit
135 hits++;
136 return dd;
137 } else {
138 // cache miss
139 misses++;
140 /*
141 * try to read from disk
142 */
143 File f = FileOps.getRealFile(pn);
144 /*
145 * is it a directory?
146 */
147 if (f.isDirectory()) {
148 dd = new DigiDirectory(f, pn, null);
149 // add to the cache
150 putDir(dd);
151 return dd;
152 } else {
153 /*
154 * then maybe a file? try the parent as a directory
155 */
156 File d = FileOps.getRealFile(dn);
157 if (d.isDirectory()) {
158 dd = new DigiDirectory(d, dn, null);
159 // add to the cache
160 putDir(dd);
161 return dd;
162 }
163 }
164 }
165 }
166 /*
167 * otherwise it's crap
168 */
169 return null;
170 }
171
172 /**
173 * Returns the DigiDirent with the pathname <code>fn</code> and the index
174 * <code>in</code> and the class <code>fc</code>.
175 *
176 * If <code>fn</code> is a file then the corresponding DocuDirent is
177 * returned and the index is ignored.
178 *
179 * @param pn
180 * digilib pathname
181 * @param in
182 * file index
183 * @param fc
184 * file class
185 * @return
186 */
187 public DigiDirent getFile(String pn, int in, int fc) {
188 // file number is 1-based, vector index is 0-based
189 int n = in - 1;
190 // get the (parent) directory
191 DigiDirectory dd = getDirectory(pn);
192 if (dd != null) {
193 // get the directory's name
194 String dn = dd.getDLPath();
195 if (dn.equals(pn)) {
196 // return the file at the index
197 return dd.get(n, fc);
198 } else {
199 // then the last part must be the filename
200 String fn = FileOps.dlName(pn);
201 return dd.get(fn);
202 }
203 }
204 return null;
205 }
206
207 /**
208 * @return long
209 */
210 public long getNumFiles() {
211 return numFiles;
212 }
213
214 /**
215 * @return long
216 */
217 public long getHits() {
218 return hits;
219 }
220
221 /**
222 * @return long
223 */
224 public long getMisses() {
225 return misses;
226 }
227
228 /**
229 * @return Returns the rootDir.
230 */
231 public DigiDirectory getRootDir() {
232 return rootDir;
233 }
234 /**
235 * @param rootDir The rootDir to set.
236 */
237 public void setRootDir(DigiDirectory rootDir) {
238 this.rootDir = rootDir;
239 }
240 }