com.berico.clavin.resolver.impl.lucene.LuceneComponentsFactory.java Source code

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Here is the source code for com.berico.clavin.resolver.impl.lucene.LuceneComponentsFactory.java

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package com.berico.clavin.resolver.impl.lucene;

import java.io.File;
import java.io.IOException;

import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.SearcherManager;
import org.apache.lucene.spatial.SpatialStrategy;
import org.apache.lucene.spatial.prefix.RecursivePrefixTreeStrategy;
import org.apache.lucene.spatial.prefix.tree.GeohashPrefixTree;
import org.apache.lucene.store.FSDirectory;
import org.apache.lucene.util.Version;

import com.spatial4j.core.context.SpatialContext;

/*#####################################################################
 * 
 * CLAVIN (Cartographic Location And Vicinity INdexer)
 * ---------------------------------------------------
 * 
 * Copyright (C) 2012-2013 Berico Technologies
 * http://clavin.bericotechnologies.com
 * 
 * ====================================================================
 * 
 * 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.
 * 
 * ====================================================================
 * 
 * LuceneComponentsFactory.java
 * 
 *###################################################################*/

/**
 * Factory for instantiating all of the Lucene components necessary to perform
 * text-based and geospatial searches in CLAVIN.
 */
public class LuceneComponentsFactory {

    SearcherManager searcherManager;
    SpatialContext spatialContext;
    SpatialStrategy spatialStrategy;
    FSDirectory index;
    IndexSearcher indexSearcher;
    Analyzer indexAnalyzer;
    File indexDir;
    IndexWriter indexWriter;

    /**
     * Instantiate with a handle to the local Lucene index.
     * YOU MUST CALL INITIALIZE WHEN YOU ARE DONE!!!!
     * 
     * @param indexDirectory Directory of the Lucene index.
     */
    public LuceneComponentsFactory(String indexDirectory) {

        this.indexDir = new File(indexDirectory);
    }

    /**
     * Initialize the common stuff used by both the IndexWriter and 
     * Searcher.
     * @throws IOException
     */
    protected void initializeCommon() throws IOException {

        // load the Lucene index directory from disk
        index = FSDirectory.open(indexDir);

        // index employs simple lower-casing & tokenizing on whitespace
        indexAnalyzer = new WhitespaceLowerCaseAnalyzer();

        // Retrieve the spatial context implementation from Spatial4j,
        // which will be used by Lucene to do it's Geo thing.
        spatialContext = SpatialContext.GEO;

        // Instantiate the spatial search strategy.
        spatialStrategy = new RecursivePrefixTreeStrategy(new GeohashPrefixTree(spatialContext, 11),
                FieldConstants.GEOMETRY);
    }

    /**
     * Initialize the IndexWriter (and other components).
     * @return This object (it's needlessly fluent!).
     * @throws IOException
     */
    public LuceneComponentsFactory initializeWriter() throws IOException {

        initializeCommon();

        // instantiate the index writer
        indexWriter = new IndexWriter(index, new IndexWriterConfig(Version.LUCENE_43, indexAnalyzer));

        return this;
    }

    /**
     * Initialize the SearcherManager (and other components).
     * @return This object (it's needlessly fluent!).
     * @throws IOException 
     */
    public LuceneComponentsFactory initializeSearcher() throws IOException {

        initializeCommon();

        // instantiate an index searcher
        indexSearcher = new IndexSearcher(DirectoryReader.open(index));

        // override default TF/IDF score to ignore multiple appearances
        indexSearcher.setSimilarity(new BinarySimilarity());

        // Instantiate the searcher manager.
        searcherManager = new SearcherManager(index, null);

        // Do it.
        return this;
    }

    /**
     * Retrieve the essential Lucene components needed to perform a faceted search.
     * @return  A wrapper class with all the necessary Lucene constructs.
     */
    public LuceneComponents getComponents() {

        return new LuceneComponents(searcherManager, spatialStrategy, spatialContext, indexAnalyzer);
    }

    /**
     * Get the SearcherManager.
     * @return SearcherManager.
     */
    public SearcherManager getSearcherManager() {
        return searcherManager;
    }

    /**
     * Get the Spatial4j Context.
     * @return Spatial4j Context.
     */
    public SpatialContext getSpatialContext() {
        return spatialContext;
    }

    /**
     * Get the Spatial4j SpatialStrategy.
     * @return SpatialStrategy.
     */
    public SpatialStrategy getSpatialStrategy() {
        return spatialStrategy;
    }

    /**
     * Get the Lucene File System directory.
     * @return FS Directory.
     */
    public FSDirectory getIndex() {
        return index;
    }

    /**
     * Get the IndexSearcher.
     * @return IndexSearcher.
     */
    public IndexSearcher getIndexSearcher() {
        return indexSearcher;
    }

    /**
     * Get the Lucene Index Analyzer.
     * @return Index Analyzer.
     */
    public Analyzer getIndexAnalyzer() {
        return indexAnalyzer;
    }

    /**
     * Get the Index Directory.
     * @return File representing the index directory.
     */
    public File getIndexDir() {
        return indexDir;
    }

    /**
     * Get the Index Writer.
     * @return Index Writer.
     */
    public IndexWriter getIndexWriter() {
        return indexWriter;
    }
}