package org.apache.lucene.index;
/**
* Copyright 2005 The Apache Software Foundation
*
* Licensed 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 java.io.File;
import java.io.IOException;
import java.io.PrintStream;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.FSDirectory;
/**
* A class to modify an index, i.e. to delete and add documents. This
* class hides {@link IndexReader} and {@link IndexWriter} so that you
* do not need to care about implementation details such as that adding
* documents is done via IndexWriter and deletion is done via IndexReader.
*
* <p>Note that you cannot create more than one <code>IndexModifier</code> object
* on the same directory at the same time.
*
* <p>Example usage:
*
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<code>
<font color="#ffffff"> </font><font color="#000000">Analyzer analyzer = </font><font color="#7f0055"><b>new </b></font><font color="#000000">StandardAnalyzer</font><font color="#000000">()</font><font color="#000000">;</font><br/>
<font color="#ffffff"> </font><font color="#3f7f5f">// create an index in /tmp/index, overwriting an existing one:</font><br/>
<font color="#ffffff"> </font><font color="#000000">IndexModifier indexModifier = </font><font color="#7f0055"><b>new </b></font><font color="#000000">IndexModifier</font><font color="#000000">(</font><font color="#2a00ff">"/tmp/index"</font><font color="#000000">, analyzer, </font><font color="#7f0055"><b>true</b></font><font color="#000000">)</font><font color="#000000">;</font><br/>
<font color="#ffffff"> </font><font color="#000000">Document doc = </font><font color="#7f0055"><b>new </b></font><font color="#000000">Document</font><font color="#000000">()</font><font color="#000000">;</font><br/>
<font color="#ffffff"> </font><font color="#000000">doc.add</font><font color="#000000">(</font><font color="#7f0055"><b>new </b></font><font color="#000000">Field</font><font color="#000000">(</font><font color="#2a00ff">"id"</font><font color="#000000">, </font><font color="#2a00ff">"1"</font><font color="#000000">, Field.Store.YES, Field.Index.UN_TOKENIZED</font><font color="#000000">))</font><font color="#000000">;</font><br/>
<font color="#ffffff"> </font><font color="#000000">doc.add</font><font color="#000000">(</font><font color="#7f0055"><b>new </b></font><font color="#000000">Field</font><font color="#000000">(</font><font color="#2a00ff">"body"</font><font color="#000000">, </font><font color="#2a00ff">"a simple test"</font><font color="#000000">, Field.Store.YES, Field.Index.TOKENIZED</font><font color="#000000">))</font><font color="#000000">;</font><br/>
<font color="#ffffff"> </font><font color="#000000">indexModifier.addDocument</font><font color="#000000">(</font><font color="#000000">doc</font><font color="#000000">)</font><font color="#000000">;</font><br/>
<font color="#ffffff"> </font><font color="#7f0055"><b>int </b></font><font color="#000000">deleted = indexModifier.delete</font><font color="#000000">(</font><font color="#7f0055"><b>new </b></font><font color="#000000">Term</font><font color="#000000">(</font><font color="#2a00ff">"id"</font><font color="#000000">, </font><font color="#2a00ff">"1"</font><font color="#000000">))</font><font color="#000000">;</font><br/>
<font color="#ffffff"> </font><font color="#000000">System.out.println</font><font color="#000000">(</font><font color="#2a00ff">"Deleted " </font><font color="#000000">+ deleted + </font><font color="#2a00ff">" document"</font><font color="#000000">)</font><font color="#000000">;</font><br/>
<font color="#ffffff"> </font><font color="#000000">indexModifier.flush</font><font color="#000000">()</font><font color="#000000">;</font><br/>
<font color="#ffffff"> </font><font color="#000000">System.out.println</font><font color="#000000">(</font><font color="#000000">indexModifier.docCount</font><font color="#000000">() </font><font color="#000000">+ </font><font color="#2a00ff">" docs in index"</font><font color="#000000">)</font><font color="#000000">;</font><br/>
<font color="#ffffff"> </font><font color="#000000">indexModifier.close</font><font color="#000000">()</font><font color="#000000">;</font></code>
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*
* <p>Not all methods of IndexReader and IndexWriter are offered by this
* class. If you need access to additional methods, either use those classes
* directly or implement your own class that extends <code>IndexModifier</code>.
*
* <p>Although an instance of this class can be used from more than one
* thread, you will not get the best performance. You might want to use
* IndexReader and IndexWriter directly for that (but you will need to
* care about synchronization yourself then).
*
* <p>While you can freely mix calls to add() and delete() using this class,
* you should batch you calls for best performance. For example, if you
* want to update 20 documents, you should first delete all those documents,
* then add all the new documents.
*
* @author Daniel Naber
*/
public class IndexModifier {
protected IndexWriter indexWriter = null;
protected IndexReader indexReader = null;
protected Directory directory = null;
protected Analyzer analyzer = null;
protected boolean open = false;
// Lucene defaults:
protected PrintStream infoStream = null;
protected boolean useCompoundFile = true;
protected int maxBufferedDocs = IndexWriter.DEFAULT_MAX_BUFFERED_DOCS;
protected int maxFieldLength = IndexWriter.DEFAULT_MAX_FIELD_LENGTH;
protected int mergeFactor = IndexWriter.DEFAULT_MERGE_FACTOR;
/**
* Open an index with write access.
*
* @param directory the index directory
* @param analyzer the analyzer to use for adding new documents
* @param create <code>true</code> to create the index or overwrite the existing one;
* <code>false</code> to append to the existing index
*/
public IndexModifier(Directory directory, Analyzer analyzer, boolean create) throws IOException {
init(directory, analyzer, create);
}
/**
* Open an index with write access.
*
* @param dirName the index directory
* @param analyzer the analyzer to use for adding new documents
* @param create <code>true</code> to create the index or overwrite the existing one;
* <code>false</code> to append to the existing index
*/
public IndexModifier(String dirName, Analyzer analyzer, boolean create) throws IOException {
Directory dir = FSDirectory.getDirectory(dirName, create);
init(dir, analyzer, create);
}
/**
* Open an index with write access.
*
* @param file the index directory
* @param analyzer the analyzer to use for adding new documents
* @param create <code>true</code> to create the index or overwrite the existing one;
* <code>false</code> to append to the existing index
*/
public IndexModifier(File file, Analyzer analyzer, boolean create) throws IOException {
Directory dir = FSDirectory.getDirectory(file, create);
init(dir, analyzer, create);
}
/**
* Initialize an IndexWriter.
* @throws IOException
*/
protected void init(Directory directory, Analyzer analyzer, boolean create) throws IOException {
this.directory = directory;
synchronized(this.directory) {
this.analyzer = analyzer;
indexWriter = new IndexWriter(directory, analyzer, create);
open = true;
}
}
/**
* Throw an IllegalStateException if the index is closed.
* @throws IllegalStateException
*/
protected void assureOpen() {
if (!open) {
throw new IllegalStateException("Index is closed");
}
}
/**
* Close the IndexReader and open an IndexWriter.
* @throws IOException
*/
protected void createIndexWriter() throws IOException {
if (indexWriter == null) {
if (indexReader != null) {
indexReader.close();
indexReader = null;
}
indexWriter = new IndexWriter(directory, analyzer, false);
indexWriter.setInfoStream(infoStream);
indexWriter.setUseCompoundFile(useCompoundFile);
indexWriter.setMaxBufferedDocs(maxBufferedDocs);
indexWriter.setMaxFieldLength(maxFieldLength);
indexWriter.setMergeFactor(mergeFactor);
}
}
/**
* Close the IndexWriter and open an IndexReader.
* @throws IOException
*/
protected void createIndexReader() throws IOException {
if (indexReader == null) {
if (indexWriter != null) {
indexWriter.close();
indexWriter = null;
}
indexReader = IndexReader.open(directory);
}
}
/**
* Make sure all changes are written to disk.
* @throws IOException
*/
public void flush() throws IOException {
synchronized(directory) {
assureOpen();
if (indexWriter != null) {
indexWriter.close();
indexWriter = null;
createIndexWriter();
} else {
indexReader.close();
indexReader = null;
createIndexReader();
}
}
}
/**
* Adds a document to this index, using the provided analyzer instead of the
* one specific in the constructor. If the document contains more than
* {@link #setMaxFieldLength(int)} terms for a given field, the remainder are
* discarded.
* @see IndexWriter#addDocument(Document, Analyzer)
* @throws IllegalStateException if the index is closed
*/
public void addDocument(Document doc, Analyzer docAnalyzer) throws IOException {
synchronized(directory) {
assureOpen();
createIndexWriter();
if (docAnalyzer != null)
indexWriter.addDocument(doc, docAnalyzer);
else
indexWriter.addDocument(doc);
}
}
/**
* Adds a document to this index. If the document contains more than
* {@link #setMaxFieldLength(int)} terms for a given field, the remainder are
* discarded.
* @see IndexWriter#addDocument(Document)
* @throws IllegalStateException if the index is closed
*/
public void addDocument(Document doc) throws IOException {
addDocument(doc, null);
}
/**
* Deletes all documents containing <code>term</code>.
* 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. Returns the number of documents deleted.
* @return the number of documents deleted
* @see IndexReader#deleteDocuments(Term)
* @throws IllegalStateException if the index is closed
*/
public int deleteDocuments(Term term) throws IOException {
synchronized(directory) {
assureOpen();
createIndexReader();
return indexReader.deleteDocuments(term);
}
}
/**
* Deletes all documents containing <code>term</code>.
* 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. Returns the number of documents deleted.
* @return the number of documents deleted
* @see IndexReader#deleteDocuments(Term)
* @throws IllegalStateException if the index is closed
* @deprecated Use {@link #deleteDocuments(Term)} instead.
*/
public int delete(Term term) throws IOException {
return deleteDocuments(term);
}
/**
* Deletes the document numbered <code>docNum</code>.
* @see IndexReader#deleteDocument(int)
* @throws IllegalStateException if the index is closed
*/
public void deleteDocument(int docNum) throws IOException {
synchronized(directory) {
assureOpen();
createIndexReader();
indexReader.deleteDocument(docNum);
}
}
/**
* Deletes the document numbered <code>docNum</code>.
* @see IndexReader#deleteDocument(int)
* @throws IllegalStateException if the index is closed
* @deprecated Use {@link #deleteDocument(int)} instead.
*/
public void delete(int docNum) throws IOException {
deleteDocument(docNum);
}
/**
* Returns the number of documents currently in this index.
* @see IndexWriter#docCount()
* @see IndexReader#numDocs()
* @throws IllegalStateException if the index is closed
*/
public int docCount() {
synchronized(directory) {
assureOpen();
if (indexWriter != null) {
return indexWriter.docCount();
} else {
return indexReader.numDocs();
}
}
}
/**
* Merges all segments together into a single segment, optimizing an index
* for search.
* @see IndexWriter#optimize()
* @throws IllegalStateException if the index is closed
*/
public void optimize() throws IOException {
synchronized(directory) {
assureOpen();
createIndexWriter();
indexWriter.optimize();
}
}
/**
* If non-null, information about merges and a message when
* {@link #getMaxFieldLength()} is reached will be printed to this.
* <p>Example: <tt>index.setInfoStream(System.err);</tt>
* @see IndexWriter#setInfoStream(PrintStream)
* @throws IllegalStateException if the index is closed
*/
public void setInfoStream(PrintStream infoStream) {
synchronized(directory) {
assureOpen();
if (indexWriter != null) {
indexWriter.setInfoStream(infoStream);
}
this.infoStream = infoStream;
}
}
/**
* @throws IOException
* @see IndexModifier#setInfoStream(PrintStream)
*/
public PrintStream getInfoStream() throws IOException {
synchronized(directory) {
assureOpen();
createIndexWriter();
return indexWriter.getInfoStream();
}
}
/**
* Setting to turn on usage of a compound file. When on, multiple files
* for each segment are merged into a single file once the segment creation
* is finished. This is done regardless of what directory is in use.
* @see IndexWriter#setUseCompoundFile(boolean)
* @throws IllegalStateException if the index is closed
*/
public void setUseCompoundFile(boolean useCompoundFile) {
synchronized(directory) {
assureOpen();
if (indexWriter != null) {
indexWriter.setUseCompoundFile(useCompoundFile);
}
this.useCompoundFile = useCompoundFile;
}
}
/**
* @throws IOException
* @see IndexModifier#setUseCompoundFile(boolean)
*/
public boolean getUseCompoundFile() throws IOException {
synchronized(directory) {
assureOpen();
createIndexWriter();
return indexWriter.getUseCompoundFile();
}
}
/**
* The maximum number of terms that will be indexed for a single field in a
* document. This limits the amount of memory required for indexing, so that
* collections with very large files will not crash the indexing process by
* running out of memory.<p/>
* Note that this effectively truncates large documents, excluding from the
* index terms that occur further in the document. If you know your source
* documents are large, be sure to set this value high enough to accomodate
* the expected size. If you set it to Integer.MAX_VALUE, then the only limit
* is your memory, but you should anticipate an OutOfMemoryError.<p/>
* By default, no more than 10,000 terms will be indexed for a field.
* @see IndexWriter#setMaxFieldLength(int)
* @throws IllegalStateException if the index is closed
*/
public void setMaxFieldLength(int maxFieldLength) {
synchronized(directory) {
assureOpen();
if (indexWriter != null) {
indexWriter.setMaxFieldLength(maxFieldLength);
}
this.maxFieldLength = maxFieldLength;
}
}
/**
* @throws IOException
* @see IndexModifier#setMaxFieldLength(int)
*/
public int getMaxFieldLength() throws IOException {
synchronized(directory) {
assureOpen();
createIndexWriter();
return indexWriter.getMaxFieldLength();
}
}
/**
* The maximum number of terms that will be indexed for a single field in a
* document. This limits the amount of memory required for indexing, so that
* collections with very large files will not crash the indexing process by
* running out of memory.<p/>
* Note that this effectively truncates large documents, excluding from the
* index terms that occur further in the document. If you know your source
* documents are large, be sure to set this value high enough to accomodate
* the expected size. If you set it to Integer.MAX_VALUE, then the only limit
* is your memory, but you should anticipate an OutOfMemoryError.<p/>
* By default, no more than 10,000 terms will be indexed for a field.
* @see IndexWriter#setMaxBufferedDocs(int)
* @throws IllegalStateException if the index is closed
*/
public void setMaxBufferedDocs(int maxBufferedDocs) {
synchronized(directory) {
assureOpen();
if (indexWriter != null) {
indexWriter.setMaxBufferedDocs(maxBufferedDocs);
}
this.maxBufferedDocs = maxBufferedDocs;
}
}
/**
* @throws IOException
* @see IndexModifier#setMaxBufferedDocs(int)
*/
public int getMaxBufferedDocs() throws IOException {
synchronized(directory) {
assureOpen();
createIndexWriter();
return indexWriter.getMaxBufferedDocs();
}
}
/**
* Determines how often segment indices are merged by addDocument(). With
* smaller values, less RAM is used while indexing, and searches on
* unoptimized indices are faster, but indexing speed is slower. With larger
* values, more RAM is used during indexing, and while searches on unoptimized
* indices are slower, indexing is faster. Thus larger values (> 10) are best
* for batch index creation, and smaller values (< 10) for indices that are
* interactively maintained.
* <p>This must never be less than 2. The default value is 10.
*
* @see IndexWriter#setMergeFactor(int)
* @throws IllegalStateException if the index is closed
*/
public void setMergeFactor(int mergeFactor) {
synchronized(directory) {
assureOpen();
if (indexWriter != null) {
indexWriter.setMergeFactor(mergeFactor);
}
this.mergeFactor = mergeFactor;
}
}
/**
* @throws IOException
* @see IndexModifier#setMergeFactor(int)
*/
public int getMergeFactor() throws IOException {
synchronized(directory) {
assureOpen();
createIndexWriter();
return indexWriter.getMergeFactor();
}
}
/**
* Close this index, writing all pending changes to disk.
*
* @throws IllegalStateException if the index has been closed before already
*/
public void close() throws IOException {
synchronized(directory) {
if (!open)
throw new IllegalStateException("Index is closed already");
if (indexWriter != null) {
indexWriter.close();
indexWriter = null;
} else {
indexReader.close();
indexReader = null;
}
open = false;
}
}
public String toString() {
return "Index@" + directory;
}
/*
// used as an example in the javadoc:
public static void main(String[] args) throws IOException {
Analyzer analyzer = new StandardAnalyzer();
// create an index in /tmp/index, overwriting an existing one:
IndexModifier indexModifier = new IndexModifier("/tmp/index", analyzer, true);
Document doc = new Document();
doc.add(new Field("id", "1", Field.Store.YES, Field.Index.UN_TOKENIZED));
doc.add(new Field("body", "a simple test", Field.Store.YES, Field.Index.TOKENIZED));
indexModifier.addDocument(doc);
int deleted = indexModifier.delete(new Term("id", "1"));
System.out.println("Deleted " + deleted + " document");
indexModifier.flush();
System.out.println(indexModifier.docCount() + " docs in index");
indexModifier.close();
}*/
}
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