servlets.TermStatsComparator.java Source code

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Here is the source code for servlets.TermStatsComparator.java

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/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package servlets;

import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.StringReader;
import java.util.Comparator;
import java.util.Properties;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.Term;
import org.apache.lucene.store.FSDirectory;
import retriever.TrecDocRetriever;
import org.apache.lucene.misc.HighFreqTerms;
import org.apache.lucene.misc.TermStats;

/**
 *
 * @author Debasis
 */
class TermStatsComparator implements Comparator<TermStats> {

    @Override
    public int compare(TermStats t, TermStats t1) {
        return new Long(t.docFreq).compareTo(new Long(t1.docFreq));
    }
}

public class TermStatsViewer extends HttpServlet {

    TrecDocRetriever retriever;

    @Override
    public void init(ServletConfig config) throws ServletException {
        String propFileName = config.getInitParameter("configFile");
        try {
            retriever = new TrecDocRetriever(propFileName);
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }

    String analyze(String query) {
        StringBuffer buff = new StringBuffer();
        try {
            Analyzer analyzer = retriever.getAnalyzer();
            TokenStream stream = analyzer.tokenStream("dummy", new StringReader(query));
            CharTermAttribute termAtt = stream.addAttribute(CharTermAttribute.class);
            stream.reset();
            while (stream.incrementToken()) {
                String term = termAtt.toString();
                buff.append(term);
                break;
            }
            stream.end();
            stream.close();
        } catch (Exception ex) {
            ex.printStackTrace();
            return query;
        }
        return buff.toString();
    }

    boolean isNumber(String str) {
        int len = str.length();
        for (int i = 0; i < len; i++) {
            if (!(str.charAt(i) >= '0' && str.charAt(i) <= '9'))
                return false;
        }
        return true;
    }

    /**
     * Processes requests for both HTTP <code>GET</code> and <code>POST</code>
     * methods.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        try (PrintWriter out = response.getWriter()) {
            /* TODO output your page here. You may use following sample code. */
            IndexReader reader = retriever.getReader();
            String term = request.getParameter("term");

            if (isNumber(term)) {
                TermStats[] termStats = null;
                try {
                    termStats = HighFreqTerms.getHighFreqTerms(reader, Integer.parseInt(term),
                            TrecDocRetriever.FIELD_ANALYZED_CONTENT, new TermStatsComparator());
                } catch (Exception ex) {
                    out.println("Error in obtaining term stats");
                }
                if (termStats == null)
                    out.println("Error in obtaining term stats");

                StringBuffer responseBuff = new StringBuffer("<table><tbody>");
                responseBuff.append("<tr>").append("<th>").append("Term").append("</th>").append("<th>")
                        .append("Doc Freq").append("</th>").append("<th>").append("Coll Freq").append("</th>")
                        .append("</tr>");

                for (TermStats ts : termStats) {
                    responseBuff.append("<tr>").append("<td>").append(ts.termtext.utf8ToString()).append("</td>")
                            .append("<td>").append(ts.docFreq).append("</td>").append("<td>")
                            .append(ts.totalTermFreq).append("</td>").append("</tr>");
                }
                responseBuff.append("</tbody></table>");
                out.println(responseBuff.toString());
            } else {
                String analyzedTerm = analyze(term);
                Term t = new Term(TrecDocRetriever.FIELD_ANALYZED_CONTENT, analyzedTerm);
                int docFreq = reader.docFreq(t);
                long collFreq = reader.totalTermFreq(t);
                out.println("Doc freq: " + docFreq + "&nbsp;&nbsp;" + "Coll Freq: " + collFreq);
            }
        }
    }

    // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
    /**
     * Handles the HTTP <code>GET</code> method.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    /**
     * Handles the HTTP <code>POST</code> method.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    /**
     * Returns a short description of the servlet.
     *
     * @return a String containing servlet description
     */
    @Override
    public String getServletInfo() {
        return "Short description";
    }// </editor-fold>

}