Source Code Cross Referenced for FSDirectory.java in  » Net » lucene-connector » org » apache » lucene » store » Java Source Code / Java DocumentationJava Source Code and Java Documentation

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Java Source Code / Java Documentation » Net » lucene connector » org.apache.lucene.store 
Source Cross Referenced  Class Diagram Java Document (Java Doc) 


001:        package org.apache.lucene.store;
002:
003:        /**
004:         * Licensed to the Apache Software Foundation (ASF) under one or more
005:         * contributor license agreements.  See the NOTICE file distributed with
006:         * this work for additional information regarding copyright ownership.
007:         * The ASF licenses this file to You under the Apache License, Version 2.0
008:         * (the "License"); you may not use this file except in compliance with
009:         * the License.  You may obtain a copy of the License at
010:         *
011:         *     http://www.apache.org/licenses/LICENSE-2.0
012:         *
013:         * Unless required by applicable law or agreed to in writing, software
014:         * distributed under the License is distributed on an "AS IS" BASIS,
015:         * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
016:         * See the License for the specific language governing permissions and
017:         * limitations under the License.
018:         */
019:
020:        import java.io.File;
021:        import java.io.FileInputStream;
022:        import java.io.FileOutputStream;
023:        import java.io.IOException;
024:        import java.io.RandomAccessFile;
025:        import java.security.MessageDigest;
026:        import java.security.NoSuchAlgorithmException;
027:        import java.util.Hashtable;
028:
029:        import org.apache.lucene.index.IndexFileNameFilter;
030:
031:        // Used only for WRITE_LOCK_NAME in deprecated create=true case:
032:        import org.apache.lucene.index.IndexWriter;
033:
034:        /**
035:         * Straightforward implementation of {@link Directory} as a directory of files.
036:         * Locking implementation is by default the {@link SimpleFSLockFactory}, but
037:         * can be changed either by passing in a {@link LockFactory} instance to
038:         * <code>getDirectory</code>, or specifying the LockFactory class by setting
039:         * <code>org.apache.lucene.store.FSDirectoryLockFactoryClass</code> Java system
040:         * property, or by calling {@link #setLockFactory} after creating
041:         * the Directory.
042:
043:         * <p>Directories are cached, so that, for a given canonical
044:         * path, the same FSDirectory instance will always be
045:         * returned by <code>getDirectory</code>.  This permits
046:         * synchronization on directories.</p>
047:         *
048:         * @see Directory
049:         * @author Doug Cutting
050:         */
051:        public class FSDirectory extends Directory {
052:
053:            /** This cache of directories ensures that there is a unique Directory
054:             * instance per path, so that synchronization on the Directory can be used to
055:             * synchronize access between readers and writers.  We use
056:             * refcounts to ensure when the last use of an FSDirectory
057:             * instance for a given canonical path is closed, we remove the
058:             * instance from the cache.  See LUCENE-776
059:             * for some relevant discussion.
060:             */
061:            private static final Hashtable DIRECTORIES = new Hashtable();
062:
063:            private static boolean disableLocks = false;
064:
065:            // TODO: should this move up to the Directory base class?  Also: should we
066:            // make a per-instance (in addition to the static "default") version?
067:
068:            /**
069:             * Set whether Lucene's use of lock files is disabled. By default, 
070:             * lock files are enabled. They should only be disabled if the index
071:             * is on a read-only medium like a CD-ROM.
072:             */
073:            public static void setDisableLocks(boolean doDisableLocks) {
074:                FSDirectory.disableLocks = doDisableLocks;
075:            }
076:
077:            /**
078:             * Returns whether Lucene's use of lock files is disabled.
079:             * @return true if locks are disabled, false if locks are enabled.
080:             */
081:            public static boolean getDisableLocks() {
082:                return FSDirectory.disableLocks;
083:            }
084:
085:            /**
086:             * Directory specified by <code>org.apache.lucene.lockDir</code>
087:             * or <code>java.io.tmpdir</code> system property.
088:
089:             * @deprecated As of 2.1, <code>LOCK_DIR</code> is unused
090:             * because the write.lock is now stored by default in the
091:             * index directory.  If you really want to store locks
092:             * elsewhere you can create your own {@link
093:             * SimpleFSLockFactory} (or {@link NativeFSLockFactory},
094:             * etc.) passing in your preferred lock directory.  Then,
095:             * pass this <code>LockFactory</code> instance to one of
096:             * the <code>getDirectory</code> methods that take a
097:             * <code>lockFactory</code> (for example, {@link #getDirectory(String, LockFactory)}).
098:             */
099:            public static final String LOCK_DIR = System.getProperty(
100:                    "org.apache.lucene.lockDir", System
101:                            .getProperty("java.io.tmpdir"));
102:
103:            /** The default class which implements filesystem-based directories. */
104:            private static Class IMPL;
105:            static {
106:                try {
107:                    String name = System.getProperty(
108:                            "org.apache.lucene.FSDirectory.class",
109:                            FSDirectory.class.getName());
110:                    IMPL = Class.forName(name);
111:                } catch (ClassNotFoundException e) {
112:                    throw new RuntimeException(
113:                            "cannot load FSDirectory class: " + e.toString(), e);
114:                } catch (SecurityException se) {
115:                    try {
116:                        IMPL = Class.forName(FSDirectory.class.getName());
117:                    } catch (ClassNotFoundException e) {
118:                        throw new RuntimeException(
119:                                "cannot load default FSDirectory class: "
120:                                        + e.toString(), e);
121:                    }
122:                }
123:            }
124:
125:            private static MessageDigest DIGESTER;
126:
127:            static {
128:                try {
129:                    DIGESTER = MessageDigest.getInstance("MD5");
130:                } catch (NoSuchAlgorithmException e) {
131:                    throw new RuntimeException(e.toString(), e);
132:                }
133:            }
134:
135:            /** A buffer optionally used in renameTo method */
136:            private byte[] buffer = null;
137:
138:            /** Returns the directory instance for the named location.
139:             * @param path the path to the directory.
140:             * @return the FSDirectory for the named file.  */
141:            public static FSDirectory getDirectory(String path)
142:                    throws IOException {
143:                return getDirectory(new File(path), null);
144:            }
145:
146:            /** Returns the directory instance for the named location.
147:             * @param path the path to the directory.
148:             * @param lockFactory instance of {@link LockFactory} providing the
149:             *        locking implementation.
150:             * @return the FSDirectory for the named file.  */
151:            public static FSDirectory getDirectory(String path,
152:                    LockFactory lockFactory) throws IOException {
153:                return getDirectory(new File(path), lockFactory);
154:            }
155:
156:            /** Returns the directory instance for the named location.
157:             * @param file the path to the directory.
158:             * @return the FSDirectory for the named file.  */
159:            public static FSDirectory getDirectory(File file)
160:                    throws IOException {
161:                return getDirectory(file, null);
162:            }
163:
164:            /** Returns the directory instance for the named location.
165:             * @param file the path to the directory.
166:             * @param lockFactory instance of {@link LockFactory} providing the
167:             *        locking implementation.
168:             * @return the FSDirectory for the named file.  */
169:            public static FSDirectory getDirectory(File file,
170:                    LockFactory lockFactory) throws IOException {
171:                file = new File(file.getCanonicalPath());
172:
173:                if (file.exists() && !file.isDirectory())
174:                    throw new IOException(file + " not a directory");
175:
176:                if (!file.exists())
177:                    if (!file.mkdirs())
178:                        throw new IOException("Cannot create directory: "
179:                                + file);
180:
181:                FSDirectory dir;
182:                synchronized (DIRECTORIES) {
183:                    dir = (FSDirectory) DIRECTORIES.get(file);
184:                    if (dir == null) {
185:                        try {
186:                            dir = (FSDirectory) IMPL.newInstance();
187:                        } catch (Exception e) {
188:                            throw new RuntimeException(
189:                                    "cannot load FSDirectory class: "
190:                                            + e.toString(), e);
191:                        }
192:                        dir.init(file, lockFactory);
193:                        DIRECTORIES.put(file, dir);
194:                    } else {
195:                        // Catch the case where a Directory is pulled from the cache, but has a
196:                        // different LockFactory instance.
197:                        if (lockFactory != null
198:                                && lockFactory != dir.getLockFactory()) {
199:                            throw new IOException(
200:                                    "Directory was previously created with a different LockFactory instance; please pass null as the lockFactory instance and use setLockFactory to change it");
201:                        }
202:                    }
203:                }
204:                synchronized (dir) {
205:                    dir.refCount++;
206:                }
207:                return dir;
208:            }
209:
210:            /** Returns the directory instance for the named location.
211:             *
212:             * @deprecated Use IndexWriter's create flag, instead, to
213:             * create a new index.
214:             *
215:             * @param path the path to the directory.
216:             * @param create if true, create, or erase any existing contents.
217:             * @return the FSDirectory for the named file.  */
218:            public static FSDirectory getDirectory(String path, boolean create)
219:                    throws IOException {
220:                return getDirectory(new File(path), create);
221:            }
222:
223:            /** Returns the directory instance for the named location.
224:             *
225:             * @deprecated Use IndexWriter's create flag, instead, to
226:             * create a new index.
227:             *
228:             * @param file the path to the directory.
229:             * @param create if true, create, or erase any existing contents.
230:             * @return the FSDirectory for the named file.  */
231:            public static FSDirectory getDirectory(File file, boolean create)
232:                    throws IOException {
233:                FSDirectory dir = getDirectory(file, null);
234:
235:                // This is now deprecated (creation should only be done
236:                // by IndexWriter):
237:                if (create) {
238:                    dir.create();
239:                }
240:
241:                return dir;
242:            }
243:
244:            private void create() throws IOException {
245:                if (directory.exists()) {
246:                    String[] files = directory.list(IndexFileNameFilter
247:                            .getFilter()); // clear old files
248:                    if (files == null)
249:                        throw new IOException("cannot read directory "
250:                                + directory.getAbsolutePath()
251:                                + ": list() returned null");
252:                    for (int i = 0; i < files.length; i++) {
253:                        File file = new File(directory, files[i]);
254:                        if (!file.delete())
255:                            throw new IOException("Cannot delete " + file);
256:                    }
257:                }
258:                lockFactory.clearLock(IndexWriter.WRITE_LOCK_NAME);
259:            }
260:
261:            private File directory = null;
262:            private int refCount;
263:
264:            protected FSDirectory() {
265:            }; // permit subclassing
266:
267:            private void init(File path, LockFactory lockFactory)
268:                    throws IOException {
269:
270:                // Set up lockFactory with cascaded defaults: if an instance was passed in,
271:                // use that; else if locks are disabled, use NoLockFactory; else if the
272:                // system property org.apache.lucene.store.FSDirectoryLockFactoryClass is set,
273:                // instantiate that; else, use SimpleFSLockFactory:
274:
275:                directory = path;
276:
277:                boolean doClearLockID = false;
278:
279:                if (lockFactory == null) {
280:
281:                    if (disableLocks) {
282:                        // Locks are disabled:
283:                        lockFactory = NoLockFactory.getNoLockFactory();
284:                    } else {
285:                        String lockClassName = System
286:                                .getProperty("org.apache.lucene.store.FSDirectoryLockFactoryClass");
287:
288:                        if (lockClassName != null && !lockClassName.equals("")) {
289:                            Class c;
290:
291:                            try {
292:                                c = Class.forName(lockClassName);
293:                            } catch (ClassNotFoundException e) {
294:                                throw new IOException(
295:                                        "unable to find LockClass "
296:                                                + lockClassName);
297:                            }
298:
299:                            try {
300:                                lockFactory = (LockFactory) c.newInstance();
301:                            } catch (IllegalAccessException e) {
302:                                throw new IOException(
303:                                        "IllegalAccessException when instantiating LockClass "
304:                                                + lockClassName);
305:                            } catch (InstantiationException e) {
306:                                throw new IOException(
307:                                        "InstantiationException when instantiating LockClass "
308:                                                + lockClassName);
309:                            } catch (ClassCastException e) {
310:                                throw new IOException(
311:                                        "unable to cast LockClass "
312:                                                + lockClassName
313:                                                + " instance to a LockFactory");
314:                            }
315:
316:                            if (lockFactory instanceof  NativeFSLockFactory) {
317:                                ((NativeFSLockFactory) lockFactory)
318:                                        .setLockDir(path);
319:                            } else if (lockFactory instanceof  SimpleFSLockFactory) {
320:                                ((SimpleFSLockFactory) lockFactory)
321:                                        .setLockDir(path);
322:                            }
323:                        } else {
324:                            // Our default lock is SimpleFSLockFactory;
325:                            // default lockDir is our index directory:
326:                            lockFactory = new SimpleFSLockFactory(path);
327:                            doClearLockID = true;
328:                        }
329:                    }
330:                }
331:
332:                setLockFactory(lockFactory);
333:
334:                if (doClearLockID) {
335:                    // Clear the prefix because write.lock will be
336:                    // stored in our directory:
337:                    lockFactory.setLockPrefix(null);
338:                }
339:            }
340:
341:            /** Returns an array of strings, one for each Lucene index file in the directory. */
342:            public String[] list() {
343:                return directory.list(IndexFileNameFilter.getFilter());
344:            }
345:
346:            /** Returns true iff a file with the given name exists. */
347:            public boolean fileExists(String name) {
348:                File file = new File(directory, name);
349:                return file.exists();
350:            }
351:
352:            /** Returns the time the named file was last modified. */
353:            public long fileModified(String name) {
354:                File file = new File(directory, name);
355:                return file.lastModified();
356:            }
357:
358:            /** Returns the time the named file was last modified. */
359:            public static long fileModified(File directory, String name) {
360:                File file = new File(directory, name);
361:                return file.lastModified();
362:            }
363:
364:            /** Set the modified time of an existing file to now. */
365:            public void touchFile(String name) {
366:                File file = new File(directory, name);
367:                file.setLastModified(System.currentTimeMillis());
368:            }
369:
370:            /** Returns the length in bytes of a file in the directory. */
371:            public long fileLength(String name) {
372:                File file = new File(directory, name);
373:                return file.length();
374:            }
375:
376:            /** Removes an existing file in the directory. */
377:            public void deleteFile(String name) throws IOException {
378:                File file = new File(directory, name);
379:                if (!file.delete())
380:                    throw new IOException("Cannot delete " + file);
381:            }
382:
383:            /** Renames an existing file in the directory. 
384:             * Warning: This is not atomic.
385:             * @deprecated 
386:             */
387:            public synchronized void renameFile(String from, String to)
388:                    throws IOException {
389:                File old = new File(directory, from);
390:                File nu = new File(directory, to);
391:
392:                /* This is not atomic.  If the program crashes between the call to
393:                   delete() and the call to renameTo() then we're screwed, but I've
394:                   been unable to figure out how else to do this... */
395:
396:                if (nu.exists())
397:                    if (!nu.delete())
398:                        throw new IOException("Cannot delete " + nu);
399:
400:                // Rename the old file to the new one. Unfortunately, the renameTo()
401:                // method does not work reliably under some JVMs.  Therefore, if the
402:                // rename fails, we manually rename by copying the old file to the new one
403:                if (!old.renameTo(nu)) {
404:                    java.io.InputStream in = null;
405:                    java.io.OutputStream out = null;
406:                    try {
407:                        in = new FileInputStream(old);
408:                        out = new FileOutputStream(nu);
409:                        // see if the buffer needs to be initialized. Initialization is
410:                        // only done on-demand since many VM's will never run into the renameTo
411:                        // bug and hence shouldn't waste 1K of mem for no reason.
412:                        if (buffer == null) {
413:                            buffer = new byte[1024];
414:                        }
415:                        int len;
416:                        while ((len = in.read(buffer)) >= 0) {
417:                            out.write(buffer, 0, len);
418:                        }
419:
420:                        // delete the old file.
421:                        old.delete();
422:                    } catch (IOException ioe) {
423:                        IOException newExc = new IOException("Cannot rename "
424:                                + old + " to " + nu);
425:                        newExc.initCause(ioe);
426:                        throw newExc;
427:                    } finally {
428:                        try {
429:                            if (in != null) {
430:                                try {
431:                                    in.close();
432:                                } catch (IOException e) {
433:                                    throw new RuntimeException(
434:                                            "Cannot close input stream: "
435:                                                    + e.toString(), e);
436:                                }
437:                            }
438:                        } finally {
439:                            if (out != null) {
440:                                try {
441:                                    out.close();
442:                                } catch (IOException e) {
443:                                    throw new RuntimeException(
444:                                            "Cannot close output stream: "
445:                                                    + e.toString(), e);
446:                                }
447:                            }
448:                        }
449:                    }
450:                }
451:            }
452:
453:            /** Creates a new, empty file in the directory with the given name.
454:                Returns a stream writing this file. */
455:            public IndexOutput createOutput(String name) throws IOException {
456:
457:                File file = new File(directory, name);
458:                if (file.exists() && !file.delete()) // delete existing, if any
459:                    throw new IOException("Cannot overwrite: " + file);
460:
461:                return new FSIndexOutput(file);
462:            }
463:
464:            // Inherit javadoc
465:            public IndexInput openInput(String name) throws IOException {
466:                return new FSIndexInput(new File(directory, name));
467:            }
468:
469:            // Inherit javadoc
470:            public IndexInput openInput(String name, int bufferSize)
471:                    throws IOException {
472:                return new FSIndexInput(new File(directory, name), bufferSize);
473:            }
474:
475:            /**
476:             * So we can do some byte-to-hexchar conversion below
477:             */
478:            private static final char[] HEX_DIGITS = { '0', '1', '2', '3', '4',
479:                    '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
480:
481:            public String getLockID() {
482:                String dirName; // name to be hashed
483:                try {
484:                    dirName = directory.getCanonicalPath();
485:                } catch (IOException e) {
486:                    throw new RuntimeException(e.toString(), e);
487:                }
488:
489:                byte digest[];
490:                synchronized (DIGESTER) {
491:                    digest = DIGESTER.digest(dirName.getBytes());
492:                }
493:                StringBuffer buf = new StringBuffer();
494:                buf.append("lucene-");
495:                for (int i = 0; i < digest.length; i++) {
496:                    int b = digest[i];
497:                    buf.append(HEX_DIGITS[(b >> 4) & 0xf]);
498:                    buf.append(HEX_DIGITS[b & 0xf]);
499:                }
500:
501:                return buf.toString();
502:            }
503:
504:            /** Closes the store to future operations. */
505:            public synchronized void close() {
506:                if (--refCount <= 0) {
507:                    synchronized (DIRECTORIES) {
508:                        DIRECTORIES.remove(directory);
509:                    }
510:                }
511:            }
512:
513:            public File getFile() {
514:                return directory;
515:            }
516:
517:            /** For debug output. */
518:            public String toString() {
519:                return this .getClass().getName() + "@" + directory;
520:            }
521:
522:            protected static class FSIndexInput extends BufferedIndexInput {
523:
524:                private static class Descriptor extends RandomAccessFile {
525:                    // remember if the file is open, so that we don't try to close it
526:                    // more than once
527:                    private boolean isOpen;
528:                    long position;
529:                    final long length;
530:
531:                    public Descriptor(File file, String mode)
532:                            throws IOException {
533:                        super (file, mode);
534:                        isOpen = true;
535:                        length = length();
536:                    }
537:
538:                    public void close() throws IOException {
539:                        if (isOpen) {
540:                            isOpen = false;
541:                            super .close();
542:                        }
543:                    }
544:
545:                    protected void finalize() throws Throwable {
546:                        try {
547:                            close();
548:                        } finally {
549:                            super .finalize();
550:                        }
551:                    }
552:                }
553:
554:                private final Descriptor file;
555:                boolean isClone;
556:
557:                public FSIndexInput(File path) throws IOException {
558:                    this (path, BufferedIndexInput.BUFFER_SIZE);
559:                }
560:
561:                public FSIndexInput(File path, int bufferSize)
562:                        throws IOException {
563:                    super (bufferSize);
564:                    file = new Descriptor(path, "r");
565:                }
566:
567:                /** IndexInput methods */
568:                protected void readInternal(byte[] b, int offset, int len)
569:                        throws IOException {
570:                    synchronized (file) {
571:                        long position = getFilePointer();
572:                        if (position != file.position) {
573:                            file.seek(position);
574:                            file.position = position;
575:                        }
576:                        int total = 0;
577:                        do {
578:                            int i = file.read(b, offset + total, len - total);
579:                            if (i == -1)
580:                                throw new IOException("read past EOF");
581:                            file.position += i;
582:                            total += i;
583:                        } while (total < len);
584:                    }
585:                }
586:
587:                public void close() throws IOException {
588:                    // only close the file if this is not a clone
589:                    if (!isClone)
590:                        file.close();
591:                }
592:
593:                protected void seekInternal(long position) {
594:                }
595:
596:                public long length() {
597:                    return file.length;
598:                }
599:
600:                public Object clone() {
601:                    FSIndexInput clone = (FSIndexInput) super .clone();
602:                    clone.isClone = true;
603:                    return clone;
604:                }
605:
606:                /** Method used for testing. Returns true if the underlying
607:                 *  file descriptor is valid.
608:                 */
609:                boolean isFDValid() throws IOException {
610:                    return file.getFD().valid();
611:                }
612:            }
613:
614:            protected static class FSIndexOutput extends BufferedIndexOutput {
615:                RandomAccessFile file = null;
616:
617:                // remember if the file is open, so that we don't try to close it
618:                // more than once
619:                private boolean isOpen;
620:
621:                public FSIndexOutput(File path) throws IOException {
622:                    file = new RandomAccessFile(path, "rw");
623:                    isOpen = true;
624:                }
625:
626:                /** output methods: */
627:                public void flushBuffer(byte[] b, int offset, int size)
628:                        throws IOException {
629:                    file.write(b, offset, size);
630:                }
631:
632:                public void close() throws IOException {
633:                    // only close the file if it has not been closed yet
634:                    if (isOpen) {
635:                        super .close();
636:                        file.close();
637:                        isOpen = false;
638:                    }
639:                }
640:
641:                /** Random-access methods */
642:                public void seek(long pos) throws IOException {
643:                    super .seek(pos);
644:                    file.seek(pos);
645:                }
646:
647:                public long length() throws IOException {
648:                    return file.length();
649:                }
650:
651:            }
652:        }
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