package org.apache.lucene.index;
/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import org.apache.lucene.document.Document;
import org.apache.lucene.document.FieldSelector;
import org.apache.lucene.search.Similarity;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.FSDirectory;
import org.apache.lucene.store.IndexInput;
import org.apache.lucene.store.Lock;
import org.apache.lucene.store.LockObtainFailedException;
import org.apache.lucene.store.AlreadyClosedException;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Arrays;
import java.util.Collection;
/** IndexReader is an abstract class, providing an interface for accessing an
index. Search of an index is done entirely through this abstract interface,
so that any subclass which implements it is searchable.
<p> Concrete subclasses of IndexReader are usually constructed with a call to
one of the static <code>open()</code> methods, e.g. {@link #open(String)}.
<p> For efficiency, in this API documents are often referred to via
<i>document numbers</i>, non-negative integers which each name a unique
document in the index. These document numbers are ephemeral--they may change
as documents are added to and deleted from an index. Clients should thus not
rely on a given document having the same number between sessions.
<p> An IndexReader can be opened on a directory for which an IndexWriter is
opened already, but it cannot be used to delete documents from the index then.
@author Doug Cutting
@version $Id: IndexReader.java 543620 2007-06-01 21:18:56Z dnaber $
*/
public abstract class IndexReader {
public static final class FieldOption {
private String option;
private FieldOption() { }
private FieldOption(String option) {
this.option = option;
}
public String toString() {
return this.option;
}
// all fields
public static final FieldOption ALL = new FieldOption ("ALL");
// all indexed fields
public static final FieldOption INDEXED = new FieldOption ("INDEXED");
// all fields that store payloads
public static final FieldOption STORES_PAYLOADS = new FieldOption ("STORES_PAYLOADS");
// all fields which are not indexed
public static final FieldOption UNINDEXED = new FieldOption ("UNINDEXED");
// all fields which are indexed with termvectors enables
public static final FieldOption INDEXED_WITH_TERMVECTOR = new FieldOption ("INDEXED_WITH_TERMVECTOR");
// all fields which are indexed but don't have termvectors enabled
public static final FieldOption INDEXED_NO_TERMVECTOR = new FieldOption ("INDEXED_NO_TERMVECTOR");
// all fields where termvectors are enabled. Please note that only standard termvector fields are returned
public static final FieldOption TERMVECTOR = new FieldOption ("TERMVECTOR");
// all field with termvectors wiht positions enabled
public static final FieldOption TERMVECTOR_WITH_POSITION = new FieldOption ("TERMVECTOR_WITH_POSITION");
// all fields where termvectors with offset position are set
public static final FieldOption TERMVECTOR_WITH_OFFSET = new FieldOption ("TERMVECTOR_WITH_OFFSET");
// all fields where termvectors with offset and position values set
public static final FieldOption TERMVECTOR_WITH_POSITION_OFFSET = new FieldOption ("TERMVECTOR_WITH_POSITION_OFFSET");
}
/**
* Constructor used if IndexReader is not owner of its directory.
* This is used for IndexReaders that are used within other IndexReaders that take care or locking directories.
*
* @param directory Directory where IndexReader files reside.
*/
protected IndexReader(Directory directory) {
this.directory = directory;
}
/**
* Constructor used if IndexReader is owner of its directory.
* If IndexReader is owner of its directory, it locks its directory in case of write operations.
*
* @param directory Directory where IndexReader files reside.
* @param segmentInfos Used for write-l
* @param closeDirectory
*/
IndexReader(Directory directory, SegmentInfos segmentInfos, boolean closeDirectory) {
init(directory, segmentInfos, closeDirectory, true);
}
void init(Directory directory, SegmentInfos segmentInfos, boolean closeDirectory, boolean directoryOwner) {
this.directory = directory;
this.segmentInfos = segmentInfos;
this.directoryOwner = directoryOwner;
this.closeDirectory = closeDirectory;
}
private Directory directory;
private boolean directoryOwner;
private boolean closeDirectory;
private IndexDeletionPolicy deletionPolicy;
private boolean closed;
/**
* @throws AlreadyClosedException if this IndexReader is closed
*/
protected final void ensureOpen() throws AlreadyClosedException {
if (closed) {
throw new AlreadyClosedException("this IndexReader is closed");
}
}
private SegmentInfos segmentInfos;
private Lock writeLock;
private boolean stale;
private boolean hasChanges;
/** Used by commit() to record pre-commit state in case
* rollback is necessary */
private boolean rollbackHasChanges;
private SegmentInfos rollbackSegmentInfos;
/** Returns an IndexReader reading the index in an FSDirectory in the named
path.
* @throws CorruptIndexException if the index is corrupt
* @throws IOException if there is a low-level IO error
* @param path the path to the index directory */
public static IndexReader open(String path) throws CorruptIndexException, IOException {
return open(FSDirectory.getDirectory(path), true, null);
}
/** Returns an IndexReader reading the index in an FSDirectory in the named
* path.
* @param path the path to the index directory
* @throws CorruptIndexException if the index is corrupt
* @throws IOException if there is a low-level IO error
*/
public static IndexReader open(File path) throws CorruptIndexException, IOException {
return open(FSDirectory.getDirectory(path), true, null);
}
/** Returns an IndexReader reading the index in the given Directory.
* @param directory the index directory
* @throws CorruptIndexException if the index is corrupt
* @throws IOException if there is a low-level IO error
*/
public static IndexReader open(final Directory directory) throws CorruptIndexException, IOException {
return open(directory, false, null);
}
/** Expert: returns an IndexReader reading the index in the given
* Directory, with a custom {@link IndexDeletionPolicy}.
* @param directory the index directory
* @param deletionPolicy a custom deletion policy (only used
* if you use this reader to perform deletes or to set
* norms); see {@link IndexWriter} for details.
* @throws CorruptIndexException if the index is corrupt
* @throws IOException if there is a low-level IO error
*/
public static IndexReader open(final Directory directory, IndexDeletionPolicy deletionPolicy) throws CorruptIndexException, IOException {
return open(directory, false, deletionPolicy);
}
private static IndexReader open(final Directory directory, final boolean closeDirectory, final IndexDeletionPolicy deletionPolicy) throws CorruptIndexException, IOException {
return (IndexReader) new SegmentInfos.FindSegmentsFile(directory) {
protected Object doBody(String segmentFileName) throws CorruptIndexException, IOException {
SegmentInfos infos = new SegmentInfos();
infos.read(directory, segmentFileName);
IndexReader reader;
if (infos.size() == 1) { // index is optimized
reader = SegmentReader.get(infos, infos.info(0), closeDirectory);
} else {
// To reduce the chance of hitting FileNotFound
// (and having to retry), we open segments in
// reverse because IndexWriter merges & deletes
// the newest segments first.
IndexReader[] readers = new IndexReader[infos.size()];
for (int i = infos.size()-1; i >= 0; i--) {
try {
readers[i] = SegmentReader.get(infos.info(i));
} catch (IOException e) {
// Close all readers we had opened:
for(i++;i<infos.size();i++) {
readers[i].close();
}
throw e;
}
}
reader = new MultiReader(directory, infos, closeDirectory, readers);
}
reader.deletionPolicy = deletionPolicy;
return reader;
}
}.run();
}
/** Returns the directory this index resides in.
*/
public Directory directory() {
ensureOpen();
return directory;
}
/**
* Returns the time the index in the named directory was last modified.
* Do not use this to check whether the reader is still up-to-date, use
* {@link #isCurrent()} instead.
* @throws CorruptIndexException if the index is corrupt
* @throws IOException if there is a low-level IO error
*/
public static long lastModified(String directory) throws CorruptIndexException, IOException {
return lastModified(new File(directory));
}
/**
* Returns the time the index in the named directory was last modified.
* Do not use this to check whether the reader is still up-to-date, use
* {@link #isCurrent()} instead.
* @throws CorruptIndexException if the index is corrupt
* @throws IOException if there is a low-level IO error
*/
public static long lastModified(File fileDirectory) throws CorruptIndexException, IOException {
return ((Long) new SegmentInfos.FindSegmentsFile(fileDirectory) {
public Object doBody(String segmentFileName) {
return new Long(FSDirectory.fileModified(fileDirectory, segmentFileName));
}
}.run()).longValue();
}
/**
* Returns the time the index in the named directory was last modified.
* Do not use this to check whether the reader is still up-to-date, use
* {@link #isCurrent()} instead.
* @throws CorruptIndexException if the index is corrupt
* @throws IOException if there is a low-level IO error
*/
public static long lastModified(final Directory directory2) throws CorruptIndexException, IOException {
return ((Long) new SegmentInfos.FindSegmentsFile(directory2) {
public Object doBody(String segmentFileName) throws IOException {
return new Long(directory2.fileModified(segmentFileName));
}
}.run()).longValue();
}
/**
* Reads version number from segments files. The version number is
* initialized with a timestamp and then increased by one for each change of
* the index.
*
* @param directory where the index resides.
* @return version number.
* @throws CorruptIndexException if the index is corrupt
* @throws IOException if there is a low-level IO error
*/
public static long getCurrentVersion(String directory) throws CorruptIndexException, IOException {
return getCurrentVersion(new File(directory));
}
/**
* Reads version number from segments files. The version number is
* initialized with a timestamp and then increased by one for each change of
* the index.
*
* @param directory where the index resides.
* @return version number.
* @throws CorruptIndexException if the index is corrupt
* @throws IOException if there is a low-level IO error
*/
public static long getCurrentVersion(File directory) throws CorruptIndexException, IOException {
Directory dir = FSDirectory.getDirectory(directory);
long version = getCurrentVersion(dir);
dir.close();
return version;
}
/**
* Reads version number from segments files. The version number is
* initialized with a timestamp and then increased by one for each change of
* the index.
*
* @param directory where the index resides.
* @return version number.
* @throws CorruptIndexException if the index is corrupt
* @throws IOException if there is a low-level IO error
*/
public static long getCurrentVersion(Directory directory) throws CorruptIndexException, IOException {
return SegmentInfos.readCurrentVersion(directory);
}
/**
* Version number when this IndexReader was opened.
*/
public long getVersion() {
ensureOpen();
return segmentInfos.getVersion();
}
/**
* Check whether this IndexReader is still using the
* current (i.e., most recently committed) version of the
* index. If a writer has committed any changes to the
* index since this reader was opened, this will return
* <code>false</code>, in which case you must open a new
* IndexReader in order to see the changes. See the
* description of the <a href="IndexWriter.html#autoCommit"><code>autoCommit</code></a>
* flag which controls when the {@link IndexWriter}
* actually commits changes to the index.
*
* @throws CorruptIndexException if the index is corrupt
* @throws IOException if there is a low-level IO error
*/
public boolean isCurrent() throws CorruptIndexException, IOException {
ensureOpen();
return SegmentInfos.readCurrentVersion(directory) == segmentInfos.getVersion();
}
/**
* Checks is the index is optimized (if it has a single segment and no deletions)
* @return <code>true</code> if the index is optimized; <code>false</code> otherwise
*/
public boolean isOptimized() {
ensureOpen();
return segmentInfos.size() == 1 && hasDeletions() == false;
}
/**
* Return an array of term frequency vectors for the specified document.
* The array contains a vector for each vectorized field in the document.
* Each vector contains terms and frequencies for all terms in a given vectorized field.
* If no such fields existed, the method returns null. The term vectors that are
* returned my either be of type TermFreqVector or of type TermPositionsVector if
* positions or offsets have been stored.
*
* @param docNumber document for which term frequency vectors are returned
* @return array of term frequency vectors. May be null if no term vectors have been
* stored for the specified document.
* @throws IOException if index cannot be accessed
* @see org.apache.lucene.document.Field.TermVector
*/
abstract public TermFreqVector[] getTermFreqVectors(int docNumber)
throws IOException;
/**
* Return a term frequency vector for the specified document and field. The
* returned vector contains terms and frequencies for the terms in
* the specified field of this document, if the field had the storeTermVector
* flag set. If termvectors had been stored with positions or offsets, a
* TermPositionsVector is returned.
*
* @param docNumber document for which the term frequency vector is returned
* @param field field for which the term frequency vector is returned.
* @return term frequency vector May be null if field does not exist in the specified
* document or term vector was not stored.
* @throws IOException if index cannot be accessed
* @see org.apache.lucene.document.Field.TermVector
*/
abstract public TermFreqVector getTermFreqVector(int docNumber, String field)
throws IOException;
/**
* Returns <code>true</code> if an index exists at the specified directory.
* If the directory does not exist or if there is no index in it.
* <code>false</code> is returned.
* @param directory the directory to check for an index
* @return <code>true</code> if an index exists; <code>false</code> otherwise
*/
public static boolean indexExists(String directory) {
return indexExists(new File(directory));
}
/**
* Returns <code>true</code> if an index exists at the specified directory.
* If the directory does not exist or if there is no index in it.
* @param directory the directory to check for an index
* @return <code>true</code> if an index exists; <code>false</code> otherwise
*/
public static boolean indexExists(File directory) {
return SegmentInfos.getCurrentSegmentGeneration(directory.list()) != -1;
}
/**
* Returns <code>true</code> if an index exists at the specified directory.
* If the directory does not exist or if there is no index in it.
* @param directory the directory to check for an index
* @return <code>true</code> if an index exists; <code>false</code> otherwise
* @throws IOException if there is a problem with accessing the index
*/
public static boolean indexExists(Directory directory) throws IOException {
return SegmentInfos.getCurrentSegmentGeneration(directory) != -1;
}
/** Returns the number of documents in this index. */
public abstract int numDocs();
/** Returns one greater than the largest possible document number.
* This may be used to, e.g., determine how big to allocate an array which
* will have an element for every document number in an index.
*/
public abstract int maxDoc();
/** Returns the stored fields of the <code>n</code><sup>th</sup>
<code>Document</code> in this index.
* @throws CorruptIndexException if the index is corrupt
* @throws IOException if there is a low-level IO error
*/
public Document document(int n) throws CorruptIndexException, IOException {
ensureOpen();
return document(n, null);
}
/**
* Get the {@link org.apache.lucene.document.Document} at the <code>n</code><sup>th</sup> position. The {@link org.apache.lucene.document.FieldSelector}
* may be used to determine what {@link org.apache.lucene.document.Field}s to load and how they should be loaded.
*
* <b>NOTE:</b> If this Reader (more specifically, the underlying <code>FieldsReader</code>) is closed before the lazy {@link org.apache.lucene.document.Field} is
* loaded an exception may be thrown. If you want the value of a lazy {@link org.apache.lucene.document.Field} to be available after closing you must
* explicitly load it or fetch the Document again with a new loader.
*
*
* @param n Get the document at the <code>n</code><sup>th</sup> position
* @param fieldSelector The {@link org.apache.lucene.document.FieldSelector} to use to determine what Fields should be loaded on the Document. May be null, in which case all Fields will be loaded.
* @return The stored fields of the {@link org.apache.lucene.document.Document} at the nth position
* @throws CorruptIndexException if the index is corrupt
* @throws IOException if there is a low-level IO error
*
* @see org.apache.lucene.document.Fieldable
* @see org.apache.lucene.document.FieldSelector
* @see org.apache.lucene.document.SetBasedFieldSelector
* @see org.apache.lucene.document.LoadFirstFieldSelector
*/
//When we convert to JDK 1.5 make this Set<String>
public abstract Document document(int n, FieldSelector fieldSelector) throws CorruptIndexException, IOException;
/** Returns true if document <i>n</i> has been deleted */
public abstract boolean isDeleted(int n);
/** Returns true if any documents have been deleted */
public abstract boolean hasDeletions();
/** Returns true if there are norms stored for this field. */
public boolean hasNorms(String field) throws IOException {
// backward compatible implementation.
// SegmentReader has an efficient implementation.
ensureOpen();
return norms(field) != null;
}
/** Returns the byte-encoded normalization factor for the named field of
* every document. This is used by the search code to score documents.
*
* @see org.apache.lucene.document.Field#setBoost(float)
*/
public abstract byte[] norms(String field) throws IOException;
/** Reads the byte-encoded normalization factor for the named field of every
* document. This is used by the search code to score documents.
*
* @see org.apache.lucene.document.Field#setBoost(float)
*/
public abstract void norms(String field, byte[] bytes, int offset)
throws IOException;
/** Expert: Resets the normalization factor for the named field of the named
* document. The norm represents the product of the field's {@link
* org.apache.lucene.document.Fieldable#setBoost(float) boost} and its {@link Similarity#lengthNorm(String,
* int) length normalization}. Thus, to preserve the length normalization
* values when resetting this, one should base the new value upon the old.
*
* @see #norms(String)
* @see Similarity#decodeNorm(byte)
* @throws StaleReaderException if the index has changed
* since this reader was opened
* @throws CorruptIndexException if the index is corrupt
* @throws LockObtainFailedException if another writer
* has this index open (<code>write.lock</code> could not
* be obtained)
* @throws IOException if there is a low-level IO error
*/
public final synchronized void setNorm(int doc, String field, byte value)
throws StaleReaderException, CorruptIndexException, LockObtainFailedException, IOException {
ensureOpen();
if(directoryOwner)
acquireWriteLock();
hasChanges = true;
doSetNorm(doc, field, value);
}
/** Implements setNorm in subclass.*/
protected abstract void doSetNorm(int doc, String field, byte value)
throws CorruptIndexException, IOException;
/** Expert: Resets the normalization factor for the named field of the named
* document.
*
* @see #norms(String)
* @see Similarity#decodeNorm(byte)
*
* @throws StaleReaderException if the index has changed
* since this reader was opened
* @throws CorruptIndexException if the index is corrupt
* @throws LockObtainFailedException if another writer
* has this index open (<code>write.lock</code> could not
* be obtained)
* @throws IOException if there is a low-level IO error
*/
public void setNorm(int doc, String field, float value)
throws StaleReaderException, CorruptIndexException, LockObtainFailedException, IOException {
ensureOpen();
setNorm(doc, field, Similarity.encodeNorm(value));
}
/** Returns an enumeration of all the terms in the index. The
* enumeration is ordered by Term.compareTo(). Each term is greater
* than all that precede it in the enumeration. Note that after
* calling terms(), {@link TermEnum#next()} must be called
* on the resulting enumeration before calling other methods such as
* {@link TermEnum#term()}.
* @throws IOException if there is a low-level IO error
*/
public abstract TermEnum terms() throws IOException;
/** Returns an enumeration of all terms starting at a given term. If
* the given term does not exist, the enumeration is positioned at the
* first term greater than the supplied therm. The enumeration is
* ordered by Term.compareTo(). Each term is greater than all that
* precede it in the enumeration.
* @throws IOException if there is a low-level IO error
*/
public abstract TermEnum terms(Term t) throws IOException;
/** Returns the number of documents containing the term <code>t</code>.
* @throws IOException if there is a low-level IO error
*/
public abstract int docFreq(Term t) throws IOException;
/** Returns an enumeration of all the documents which contain
* <code>term</code>. For each document, the document number, the frequency of
* the term in that document is also provided, for use in search scoring.
* Thus, this method implements the mapping:
* <p><ul>
* Term => <docNum, freq><sup>*</sup>
* </ul>
* <p>The enumeration is ordered by document number. Each document number
* is greater than all that precede it in the enumeration.
* @throws IOException if there is a low-level IO error
*/
public TermDocs termDocs(Term term) throws IOException {
ensureOpen();
TermDocs termDocs = termDocs();
termDocs.seek(term);
return termDocs;
}
/** Returns an unpositioned {@link TermDocs} enumerator.
* @throws IOException if there is a low-level IO error
*/
public abstract TermDocs termDocs() throws IOException;
/** Returns an enumeration of all the documents which contain
* <code>term</code>. For each document, in addition to the document number
* and frequency of the term in that document, a list of all of the ordinal
* positions of the term in the document is available. Thus, this method
* implements the mapping:
*
* <p><ul>
* Term => <docNum, freq,
* <pos<sub>1</sub>, pos<sub>2</sub>, ...
* pos<sub>freq-1</sub>>
* ><sup>*</sup>
* </ul>
* <p> This positional information faciliates phrase and proximity searching.
* <p>The enumeration is ordered by document number. Each document number is
* greater than all that precede it in the enumeration.
* @throws IOException if there is a low-level IO error
*/
public TermPositions termPositions(Term term) throws IOException {
ensureOpen();
TermPositions termPositions = termPositions();
termPositions.seek(term);
return termPositions;
}
/** Returns an unpositioned {@link TermPositions} enumerator.
* @throws IOException if there is a low-level IO error
*/
public abstract TermPositions termPositions() throws IOException;
/**
* Tries to acquire the WriteLock on this directory.
* this method is only valid if this IndexReader is directory owner.
*
* @throws StaleReaderException if the index has changed
* since this reader was opened
* @throws CorruptIndexException if the index is corrupt
* @throws LockObtainFailedException if another writer
* has this index open (<code>write.lock</code> could not
* be obtained)
* @throws IOException if there is a low-level IO error
*/
private void acquireWriteLock() throws StaleReaderException, CorruptIndexException, LockObtainFailedException, IOException {
ensureOpen();
if (stale)
throw new StaleReaderException("IndexReader out of date and no longer valid for delete, undelete, or setNorm operations");
if (writeLock == null) {
Lock writeLock = directory.makeLock(IndexWriter.WRITE_LOCK_NAME);
if (!writeLock.obtain(IndexWriter.WRITE_LOCK_TIMEOUT)) // obtain write lock
throw new LockObtainFailedException("Index locked for write: " + writeLock);
this.writeLock = writeLock;
// we have to check whether index has changed since this reader was opened.
// if so, this reader is no longer valid for deletion
if (SegmentInfos.readCurrentVersion(directory) > segmentInfos.getVersion()) {
stale = true;
this.writeLock.release();
this.writeLock = null;
throw new StaleReaderException("IndexReader out of date and no longer valid for delete, undelete, or setNorm operations");
}
}
}
/** Deletes the document numbered <code>docNum</code>. Once a document is
* deleted it will not appear in TermDocs or TermPostitions enumerations.
* Attempts to read its field with the {@link #document}
* method will result in an error. The presence of this document may still be
* reflected in the {@link #docFreq} statistic, though
* this will be corrected eventually as the index is further modified.
*
* @throws StaleReaderException if the index has changed
* since this reader was opened
* @throws CorruptIndexException if the index is corrupt
* @throws LockObtainFailedException if another writer
* has this index open (<code>write.lock</code> could not
* be obtained)
* @throws IOException if there is a low-level IO error
*/
public final synchronized void deleteDocument(int docNum) throws StaleReaderException, CorruptIndexException, LockObtainFailedException, IOException {
ensureOpen();
if(directoryOwner)
acquireWriteLock();
hasChanges = true;
doDelete(docNum);
}
/** Implements deletion of the document numbered <code>docNum</code>.
* Applications should call {@link #deleteDocument(int)} or {@link #deleteDocuments(Term)}.
*/
protected abstract void doDelete(int docNum) throws CorruptIndexException, IOException;
/** Deletes all documents that have a given <code>term</code> indexed.
* This is useful if one uses a document field to hold a unique ID string for
* the document. Then to delete such a document, one merely constructs a
* term with the appropriate field and the unique ID string as its text and
* passes it to this method.
* See {@link #deleteDocument(int)} for information about when this deletion will
* become effective.
*
* @return the number of documents deleted
* @throws StaleReaderException if the index has changed
* since this reader was opened
* @throws CorruptIndexException if the index is corrupt
* @throws LockObtainFailedException if another writer
* has this index open (<code>write.lock</code> could not
* be obtained)
* @throws IOException if there is a low-level IO error
*/
public final int deleteDocuments(Term term) throws StaleReaderException, CorruptIndexException, LockObtainFailedException, IOException {
ensureOpen();
TermDocs docs = termDocs(term);
if (docs == null) return 0;
int n = 0;
try {
while (docs.next()) {
deleteDocument(docs.doc());
n++;
}
} finally {
docs.close();
}
return n;
}
/** Undeletes all documents currently marked as deleted in this index.
*
* @throws StaleReaderException if the index has changed
* since this reader was opened
* @throws LockObtainFailedException if another writer
* has this index open (<code>write.lock</code> could not
* be obtained)
* @throws CorruptIndexException if the index is corrupt
* @throws IOException if there is a low-level IO error
*/
public final synchronized void undeleteAll() throws StaleReaderException, CorruptIndexException, LockObtainFailedException, IOException {
ensureOpen();
if(directoryOwner)
acquireWriteLock();
hasChanges = true;
doUndeleteAll();
}
/** Implements actual undeleteAll() in subclass. */
protected abstract void doUndeleteAll() throws CorruptIndexException, IOException;
/**
* Should internally checkpoint state that will change
* during commit so that we can rollback if necessary.
*/
void startCommit() {
if (directoryOwner) {
rollbackSegmentInfos = (SegmentInfos) segmentInfos.clone();
}
rollbackHasChanges = hasChanges;
}
/**
* Rolls back state to just before the commit (this is
* called by commit() if there is some exception while
* committing).
*/
void rollbackCommit() {
if (directoryOwner) {
for(int i=0;i<segmentInfos.size();i++) {
// Rollback each segmentInfo. Because the
// SegmentReader holds a reference to the
// SegmentInfo we can't [easily] just replace
// segmentInfos, so we reset it in place instead:
segmentInfos.info(i).reset(rollbackSegmentInfos.info(i));
}
rollbackSegmentInfos = null;
}
hasChanges = rollbackHasChanges;
}
/**
* Commit changes resulting from delete, undeleteAll, or
* setNorm operations
*
* If an exception is hit, then either no changes or all
* changes will have been committed to the index
* (transactional semantics).
* @throws IOException if there is a low-level IO error
*/
protected final synchronized void commit() throws IOException {
if(hasChanges){
if(directoryOwner){
// Default deleter (for backwards compatibility) is
// KeepOnlyLastCommitDeleter:
IndexFileDeleter deleter = new IndexFileDeleter(directory,
deletionPolicy == null ? new KeepOnlyLastCommitDeletionPolicy() : deletionPolicy,
segmentInfos, null);
// Checkpoint the state we are about to change, in
// case we have to roll back:
startCommit();
boolean success = false;
try {
doCommit();
segmentInfos.write(directory);
success = true;
} finally {
if (!success) {
// Rollback changes that were made to
// SegmentInfos but failed to get [fully]
// committed. This way this reader instance
// remains consistent (matched to what's
// actually in the index):
rollbackCommit();
// Recompute deletable files & remove them (so
// partially written .del files, etc, are
// removed):
deleter.refresh();
}
}
// Have the deleter remove any now unreferenced
// files due to this commit:
deleter.checkpoint(segmentInfos, true);
if (writeLock != null) {
writeLock.release(); // release write lock
writeLock = null;
}
}
else
doCommit();
}
hasChanges = false;
}
/** Implements commit. */
protected abstract void doCommit() throws IOException;
/**
* Closes files associated with this index.
* Also saves any new deletions to disk.
* No other methods should be called after this has been called.
* @throws IOException if there is a low-level IO error
*/
public final synchronized void close() throws IOException {
if (!closed) {
commit();
doClose();
if (directoryOwner)
closed = true;
if(closeDirectory)
directory.close();
}
}
/** Implements close. */
protected abstract void doClose() throws IOException;
/** Release the write lock, if needed. */
protected void finalize() throws Throwable {
try {
if (writeLock != null) {
writeLock.release(); // release write lock
writeLock = null;
}
} finally {
super.finalize();
}
}
/**
* Get a list of unique field names that exist in this index and have the specified
* field option information.
* @param fldOption specifies which field option should be available for the returned fields
* @return Collection of Strings indicating the names of the fields.
* @see IndexReader.FieldOption
*/
public abstract Collection getFieldNames(FieldOption fldOption);
/**
* Returns <code>true</code> iff the index in the named directory is
* currently locked.
* @param directory the directory to check for a lock
* @throws IOException if there is a low-level IO error
*/
public static boolean isLocked(Directory directory) throws IOException {
return
directory.makeLock(IndexWriter.WRITE_LOCK_NAME).isLocked();
}
/**
* Returns <code>true</code> iff the index in the named directory is
* currently locked.
* @param directory the directory to check for a lock
* @throws IOException if there is a low-level IO error
*/
public static boolean isLocked(String directory) throws IOException {
Directory dir = FSDirectory.getDirectory(directory);
boolean result = isLocked(dir);
dir.close();
return result;
}
/**
* Forcibly unlocks the index in the named directory.
* <P>
* Caution: this should only be used by failure recovery code,
* when it is known that no other process nor thread is in fact
* currently accessing this index.
*/
public static void unlock(Directory directory) throws IOException {
directory.makeLock(IndexWriter.WRITE_LOCK_NAME).release();
}
/**
* Prints the filename and size of each file within a given compound file.
* Add the -extract flag to extract files to the current working directory.
* In order to make the extracted version of the index work, you have to copy
* the segments file from the compound index into the directory where the extracted files are stored.
* @param args Usage: org.apache.lucene.index.IndexReader [-extract] <cfsfile>
*/
public static void main(String [] args) {
String filename = null;
boolean extract = false;
for (int i = 0; i < args.length; ++i) {
if (args[i].equals("-extract")) {
extract = true;
} else if (filename == null) {
filename = args[i];
}
}
if (filename == null) {
System.out.println("Usage: org.apache.lucene.index.IndexReader [-extract] <cfsfile>");
return;
}
Directory dir = null;
CompoundFileReader cfr = null;
try {
File file = new File(filename);
String dirname = file.getAbsoluteFile().getParent();
filename = file.getName();
dir = FSDirectory.getDirectory(dirname);
cfr = new CompoundFileReader(dir, filename);
String [] files = cfr.list();
Arrays.sort(files); // sort the array of filename so that the output is more readable
for (int i = 0; i < files.length; ++i) {
long len = cfr.fileLength(files[i]);
if (extract) {
System.out.println("extract " + files[i] + " with " + len + " bytes to local directory...");
IndexInput ii = cfr.openInput(files[i]);
FileOutputStream f = new FileOutputStream(files[i]);
// read and write with a small buffer, which is more effectiv than reading byte by byte
byte[] buffer = new byte[1024];
int chunk = buffer.length;
while(len > 0) {
final int bufLen = (int) Math.min(chunk, len);
ii.readBytes(buffer, 0, bufLen);
f.write(buffer, 0, bufLen);
len -= bufLen;
}
f.close();
ii.close();
}
else
System.out.println(files[i] + ": " + len + " bytes");
}
} catch (IOException ioe) {
ioe.printStackTrace();
}
finally {
try {
if (dir != null)
dir.close();
if (cfr != null)
cfr.close();
}
catch (IOException ioe) {
ioe.printStackTrace();
}
}
}
}
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