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comparison servlet/src/digilib/io/DocuDirCache.java @ 290:5d0c0da080ec gen2 scaleable_1

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digilib servlet version 2 ("scaleable digilib") - first stab at using thread pools to limit resource use - using Dug Leas util.concurrent - doesn't mix with tomcat :-(
author robcast
date Thu, 21 Oct 2004 20:53:37 +0200
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289:9f7b864f955f 290:5d0c0da080ec
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.Iterator;
28 import java.util.LinkedList;
29 import java.util.List;
30 import java.util.Map;
31
32 import org.apache.log4j.Logger;
33
34 import digilib.servlet.DigilibConfiguration;
35
36 /**
37 * @author casties
38 */
39 public class DocuDirCache {
40
41 /** general logger for this class */
42 Logger logger = Logger.getLogger(this.getClass());
43
44 /** HashMap of directories */
45 Map map = null;
46
47 /** names of base directories */
48 String[] baseDirNames = null;
49
50 /** array of allowed file classes (image/text) */
51 private int[] fileClasses = null;
52
53 /** number of files in the whole cache (approximate) */
54 long numFiles = 0;
55
56 /** number of cache hits */
57 long hits = 0;
58
59 /** number of cache misses */
60 long misses = 0;
61
62 /** use safe (but slow) indexing */
63 boolean safeDirIndex = false;
64
65 /** the root directory element */
66 public static Directory ROOT = null;
67
68 /**
69 * Constructor with array of base directory names and file classes.
70 *
71 * @param bd
72 * base directory names
73 */
74 public DocuDirCache(String[] bd, int[] fileClasses,
75 DigilibConfiguration dlConfig) {
76 baseDirNames = bd;
77 map = new HashMap();
78 this.fileClasses = fileClasses;
79 safeDirIndex = dlConfig.getAsBoolean("safe-dir-index");
80 }
81
82 /**
83 * Constructor with array of base directory names.
84 *
85 * @param bd
86 * base directory names
87 */
88 public DocuDirCache(String[] bd) {
89 baseDirNames = bd;
90 map = new HashMap();
91 // default file class is CLASS_IMAGE
92 fileClasses = new int[1];
93 fileClasses[0] = FileOps.CLASS_IMAGE;
94 }
95
96 /**
97 * The number of directories in the cache.
98 *
99 * @return
100 */
101 public int size() {
102 return (map != null) ? map.size() : 0;
103 }
104
105 /**
106 * Add a DocuDirectory to the cache.
107 *
108 * @param newdir
109 */
110 public void put(DocuDirectory newdir) {
111 String s = newdir.getDirName();
112 if (map.containsKey(s)) {
113 logger.warn("Duplicate key in DocuDirCache.put -- ignoring!");
114 } else {
115 map.put(s, newdir);
116 numFiles += newdir.size();
117 }
118 }
119
120 /**
121 * Add a directory to the cache and check its parents.
122 *
123 * @param newDir
124 */
125 public synchronized void putDir(DocuDirectory newDir) {
126 put(newDir);
127 String parent = FileOps.parent(newDir.getDirName());
128 if (parent != "") {
129 // check the parent in the cache
130 DocuDirectory pd = (DocuDirectory) map.get(parent);
131 if (pd == null) {
132 // the parent is unknown
133 pd = new DocuDirectory(parent, this);
134 putDir(pd);
135 }
136 newDir.setParent(pd);
137 }
138 }
139
140 /**
141 * Get a list with all children of a directory.
142 *
143 * Returns a List of DocuDirectory's. Returns an empty List if the directory
144 * has no children. If recurse is false then only direct children are
145 * returned.
146 *
147 * @param dirname
148 * @param recurse
149 * find all children and their children.
150 * @return
151 */
152 public List getChildren(String dirname, boolean recurse) {
153 List l = new LinkedList();
154 for (Iterator i = map.keySet().iterator(); i.hasNext();) {
155 String n = (String) i.next();
156 DocuDirectory dd = (DocuDirectory) map.get(n);
157 if (recurse) {
158 if (dd.getDirName().startsWith(dirname)) {
159 l.add(dd);
160 }
161 } else {
162 if (FileOps.parent(dd.getDirName()).equals(dirname)) {
163 l.add(dd);
164 }
165 }
166 }
167 return l;
168 }
169
170 /**
171 * Returns the DocuDirent with the pathname <code>fn</code> and the index
172 * <code>in</code> and the class <code>fc</code>.
173 *
174 * If <code>fn</code> is a file then the corresponding DocuDirent is
175 * returned and the index is ignored.
176 *
177 * @param fn
178 * digilib pathname
179 * @param in
180 * file index
181 * @param fc
182 * file class
183 * @return
184 */
185 public DocuDirent getFile(String fn, int in, int fc) {
186 DocuDirectory dd;
187 // file number is 1-based, vector index is 0-based
188 int n = in - 1;
189 // first, assume fn is a directory and look in the cache
190 dd = (DocuDirectory) map.get(fn);
191 if (dd == null) {
192 // cache miss
193 misses++;
194 /*
195 * see if fn is a directory
196 */
197 File f = new File(baseDirNames[0], fn);
198 if (f.isDirectory()) {
199 dd = new DocuDirectory(fn, this);
200 if (dd.isValid()) {
201 // add to the cache
202 putDir(dd);
203 }
204 } else {
205 /*
206 * maybe it's a file
207 */
208 // get the parent directory string (like we store it in the
209 // cache)
210 String d = FileOps.parent(fn);
211 // try it in the cache
212 dd = (DocuDirectory) map.get(d);
213 if (dd == null) {
214 // try to read from disk
215 dd = new DocuDirectory(d, this);
216 if (dd.isValid()) {
217 // add to the cache
218 putDir(dd);
219 } else {
220 // invalid path
221 return null;
222 }
223 } else {
224 // it was not a real cache miss
225 misses--;
226 }
227 // get the file's index
228 n = dd.indexOf(f.getName(), fc);
229 }
230 } else {
231 // cache hit
232 hits++;
233 }
234 dd.refresh();
235 if (dd.isValid()) {
236 try {
237 return dd.get(n, fc);
238 } catch (IndexOutOfBoundsException e) {
239 }
240 }
241 return null;
242 }
243
244 /**
245 * Returns the DocuDirectory indicated by the pathname <code>fn</code>.
246 *
247 * If <code>fn</code> is a file then its parent directory is returned.
248 *
249 * @param fn
250 * digilib pathname
251 * @return
252 */
253 public DocuDirectory getDirectory(String fn) {
254 DocuDirectory dd;
255 // first, assume fn is a directory and look in the cache
256 dd = (DocuDirectory) map.get(fn);
257 if (dd == null) {
258 // cache miss
259 misses++;
260 // see if it's a directory
261 File f = new File(baseDirNames[0], fn);
262 if (f.isDirectory()) {
263 dd = new DocuDirectory(fn, this);
264 if (dd.isValid()) {
265 // add to the cache
266 putDir(dd);
267 }
268 } else {
269 // maybe it's a file
270 if (f.canRead()) {
271 // try the parent directory in the cache
272 dd = (DocuDirectory) map.get(f.getParent());
273 if (dd == null) {
274 // try to read from disk
275 dd = new DocuDirectory(f.getParent(), this);
276 if (dd.isValid()) {
277 // add to the cache
278 putDir(dd);
279 } else {
280 // invalid path
281 return null;
282 }
283 } else {
284 // not a real cache miss then
285 misses--;
286 }
287 } else {
288 // it's not even a file :-(
289 return null;
290 }
291 }
292 } else {
293 // cache hit
294 hits++;
295 }
296 dd.refresh();
297 if (dd.isValid()) {
298 return dd;
299 }
300 return null;
301 }
302
303 /**
304 * @return String[]
305 */
306 public String[] getBaseDirNames() {
307 return baseDirNames;
308 }
309
310 /**
311 * @return long
312 */
313 public long getNumFiles() {
314 return numFiles;
315 }
316
317 /**
318 * Sets the baseDirNames.
319 *
320 * @param baseDirNames
321 * The baseDirNames to set
322 */
323 public void setBaseDirNames(String[] baseDirNames) {
324 this.baseDirNames = baseDirNames;
325 }
326
327 /**
328 * @return long
329 */
330 public long getHits() {
331 return hits;
332 }
333
334 /**
335 * @return long
336 */
337 public long getMisses() {
338 return misses;
339 }
340
341 /**
342 * @return
343 */
344 public int[] getFileClasses() {
345 return fileClasses;
346 }
347
348 /**
349 * @param fileClasses
350 */
351 public void setFileClasses(int[] fileClasses) {
352 this.fileClasses = fileClasses;
353 }
354
355 }