ca.gnewton.lusql.core.IndexTermFreqCache.java Source code

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Here is the source code for ca.gnewton.lusql.core.IndexTermFreqCache.java

Source

package ca.gnewton.lusql.core;

import java.util.*;
import java.io.*;
import org.apache.lucene.index.*;

import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.*;
import org.apache.lucene.store.*;

/**
 * Cache for Lucene Index Term Frequency
 *
 *
 * Created: Wed Aug 13 12:04:19 2008
 * Copyright 2008 National Research Council
 * License: GNU Apache v2 http://www.apache.org/licenses/LICENSE-2.0.txtk
 *
 * @author <a href="mailto:glen.newton@gmail.com">Glen Newton</a>CISTI Research, National Research Council
 * @version 0.9
 */
public class IndexTermFreqCache {

    /**
     * Describe reader here.
     */
    private IndexReader reader;

    /**
     * Describe fieldName here.
     */
    private String fieldName;

    /**
     * Describe preload here.
     */
    private boolean preload = false;

    Map<String, Integer> cache = null;

    public IndexTermFreqCache(final IndexReader newReader, final String newFieldName, int initSize,
            boolean newPreload) throws IOException {
        setPreload(newPreload);
        setReader(newReader);
        setFieldName(newFieldName);
        cache = new HashMap<String, Integer>(initSize);
        if (preload) {
            TermEnum te = reader.terms();
            while (te.next()) {
                Term term = te.term();
                /*
                System.out.println(te.term().field()
                         + ": "
                         + te.term().text()
                         + ": "
                         + reader.docFreq(term));
                */
                if (term.field().equals(fieldName)) {
                    cache.put(te.term().text(), new Integer(reader.docFreq(term)));

                }
            }
        }
    }

    public int count() {
        return cache.size();
    }

    public int docFreq(final String termString) throws IOException {
        if (preload || cache.containsKey(termString))
            return cache.get(termString);
        else {
            Term tmpTerm = new Term(fieldName, termString);
            int freq = reader.docFreq(tmpTerm);
            cache.put(termString, new Integer(freq));
            return freq;
        }
    }

    /**
     * Get the <code>Reader</code> value.
     *
     * @return an <code>IndexReader</code> value
     */
    public final IndexReader getReader() {
        return reader;
    }

    /**
     * Set the <code>Reader</code> value.
     *
     * @param newReader The new Reader value.
     */
    public final void setReader(final IndexReader newReader) {
        this.reader = newReader;
    }

    /**
     * Get the <code>FieldName</code> value.
     *
     * @return a <code>String</code> value
     */
    public final String getFieldName() {
        return fieldName;
    }

    /**
     * Set the <code>FieldName</code> value.
     *
     * @param newFieldName The new FieldName value.
     */
    public final void setFieldName(final String newFieldName) {
        this.fieldName = newFieldName;
    }

    /**
     * Describe <code>main</code> method here.
     *
     * @param args a <code>String</code> value
     */
    public static final void main(final String[] args) {
        String dir = "itfcTestIndex";
        String cachedField = "title";
        try {
            IndexWriterConfig config = new IndexWriterConfig(LuSql.luceneVersion,
                    new StandardAnalyzer(LuSql.luceneVersion)).setOpenMode(IndexWriterConfig.OpenMode.CREATE);

            IndexWriter writer = new IndexWriter(FSDirectory.open(new File(dir)), config);

            // Doc #1
            Document doc1 = new Document();
            Field title1 = new org.apache.lucene.document.Field(cachedField, "The Rain in Spain is plain",
                    Field.Store.NO, Field.Index.ANALYZED, Field.TermVector.YES);
            doc1.add(title1);
            org.apache.lucene.document.Field ab1 = new org.apache.lucene.document.Field("ab",
                    "This is the test abstract", Field.Store.NO, Field.Index.ANALYZED, Field.TermVector.YES);
            doc1.add(ab1);
            writer.addDocument(doc1);

            // Doc #2
            Document doc2 = new Document();
            Field title2 = new org.apache.lucene.document.Field(cachedField, "This is the test plain title",
                    Field.Store.NO, Field.Index.ANALYZED, Field.TermVector.YES);
            doc2.add(title2);
            org.apache.lucene.document.Field ab2 = new org.apache.lucene.document.Field("ab",
                    "This is the test abstract", Field.Store.NO, Field.Index.ANALYZED, Field.TermVector.YES);
            doc2.add(ab2);
            writer.addDocument(doc2);

            writer.close();

            IndexReader reader = IndexReader.open(FSDirectory.open(new File(dir)));
            IndexTermFreqCache cache = new IndexTermFreqCache(reader, cachedField, 100, true);
            System.err.println(cache);
        } catch (Throwable t) {
            t.printStackTrace();
        }

    }

    public String toString() {
        StringBuffer sb = new StringBuffer();
        Iterator<String> it = cache.keySet().iterator();
        while (it.hasNext()) {
            String key = it.next();
            sb.append("\n" + getFieldName() + ":\t" + cache.get(key) + ":\t" + key);
        }
        return sb.toString();
    }

    /**
     * Get the <code>Preload</code> value.
     *
     * @return a <code>boolean</code> value
     */
    public final boolean isPreload() {
        return preload;
    }

    /**
     * Set the <code>Preload</code> value.
     *
     * @param newPreload The new Preload value.
     */
    public final void setPreload(final boolean newPreload) {
        this.preload = newPreload;
    }
} ///////