ir.project.IndexerForSNAP.java Source code

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Here is the source code for ir.project.IndexerForSNAP.java

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package ir.project;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.Iterator;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.en.EnglishAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.FieldType;
import org.apache.lucene.document.StringField;
import org.apache.lucene.document.TextField;
import org.apache.lucene.index.IndexOptions;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.RAMDirectory;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;

/**
 * Class that creates an index from JSON file.
 * @author elise
 */
public class IndexerForSNAP {

    private Directory index;

    /**
     * Default constructor.
     */
    public IndexerForSNAP() {
        this.index = new RAMDirectory();
    }

    /**
     * 
     * @return 
     */
    public Directory getIndex() {
        return this.index;
    }

    /**
     * 
     * @param filename 
     */
    public void index(String filename) {
        try {
            Analyzer analyzer = new EnglishAnalyzer(); // Use EnglishAnalyzer, so that Lucene auto stems the tokens.

            IndexWriterConfig config = new IndexWriterConfig(analyzer);
            IndexWriter w = new IndexWriter(this.index, config);

            indexFromJSON(w, filename); // Start the indexing process, the results will be in the index variable.

            w.close();

        } catch (IOException ex) {
            Logger.getLogger(IndexerForSNAP.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

    /**
     * 
     * @param w
     * @param filename 
     */
    private void indexFromJSON(IndexWriter w, String filename) {

        BufferedReader br = null;

        try {

            String sCurrentLine;

            br = new BufferedReader(new FileReader(filename));

            while ((sCurrentLine = br.readLine()) != null) {

                JSONParser parser = new JSONParser();
                JSONObject doc = (JSONObject) parser.parse(sCurrentLine);
                String text = (String) doc.get("reviewText");
                addDoc(w, text);
            }

        } catch (IOException e) {
            e.printStackTrace();
        } catch (ParseException ex) {
            Logger.getLogger(IndexerForSNAP.class.getName()).log(Level.SEVERE, null, ex);
        } finally {
            try {
                if (br != null)
                    br.close();
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }
    }

    /**
     * 
     * @param w
     * @param title
     * @param isbn
     * @param author
     * @param text
     * @throws IOException 
     */
    private void addDoc(IndexWriter w, String text) throws IOException {
        //(some of this inspired by: http://www.lucenetutorial.com/lucene-in-5-minutes.html)

        Document doc = new Document();

        FieldType type = new FieldType(); // Field for full-text or review: we want to store term vectors.

        type.setIndexOptions(IndexOptions.DOCS_AND_FREQS_AND_POSITIONS_AND_OFFSETS);
        type.setStored(true);
        type.setStoreTermVectors(true);
        type.setTokenized(true);
        type.setStoreTermVectorOffsets(true);

        Field field = new Field("text", text, type);

        doc.add(field);

        w.addDocument(doc);
    }

}