indexbuilder.java

一个功能较为完善的论坛

/*
 * XP Forum
 *
 * Copyright (c) 2002-2003 RedSoft Group.  All rights reserved.
 *
 */
package org.redsoft.forum.search;

import java.util.Collection;
import java.util.Iterator;
import java.sql.SQLException;
import java.io.IOException;

import org.apache.lucene.document.Document;
import org.apache.lucene.analysis.cn.ChineseAnalyzer;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.document.Field;

import org.redsoft.forum.ForumConstants;
import org.redsoft.forum.web.Thread;
import org.redsoft.forum.dao.DAOFactory;
import org.redsoft.forum.dao.ThreadDAO;
import org.redsoft.forum.fixture.MysqlFixture;

/**
 * Build index for all threads in db
 * If index is not built before, get all threads in db and build the index
 * If index has been built, append newly posted threads to index
 *
 * @author cinc
 * @version $Id: IndexBuilder.java,v 1.3 2003/08/01 02:56:28 cinc Exp $
 */

public class IndexBuilder{
    /**
     * Index directory
     */
    private String indexDir;

    /**
     * Constructor
     *
     * @param   indexDir    the index directory
     */
    public IndexBuilder( String indexDir ){
        System.out.println ("IndexBuilder Initialzed ok.");
        this.indexDir = indexDir;
    }

    /**
     * Check if index is built before
     */
    private boolean isIndexExist(){
        return IndexReader.indexExists( indexDir );
    }

    /**
     * Adding Thread to index
     * @throws IOException
     */
    public synchronized void buildIndex() throws IOException, SQLException {
        ThreadDAO dao = DAOFactory.getInstance().getThreadDAO();
        IndexWriter writer;
        Collection threads;
        if ( isIndexExist() ) {
            //System.out.println( "Index already existed." );
            writer = new IndexWriter( indexDir, new ChineseAnalyzer(), false );
            threads = dao.findThreadsPostedLaterThan( lastedModified() );
        } else {
            System.out.println( "Building index for threads from scratch..." );
            writer = new IndexWriter( indexDir, new ChineseAnalyzer(), true );
            threads = dao.findThreadsPostedLaterThan( 0 );
        }
        appendThreadsToIndex(threads, writer);
        writer.optimize();
        writer.close();
    }

    private void appendThreadsToIndex(Collection threads, IndexWriter writer) throws IOException {
        if (threads.size() == 0){
            System.out.println ("No newly posted threads, doing nothing.");
            return;
        }
        Iterator iterator = threads.iterator();
        while( iterator.hasNext() ){
            Thread thread = (Thread)iterator.next();
            System.out.println ( "Adding article "+ thread.getTitle() + " to index" );
            writer.addDocument( createDocument(thread) );
        }
    }

    /**
     * Get the time index is last modified
     */
    public long lastedModified() throws IOException{
        return IndexReader.lastModified( indexDir );
    }

    /**
     * create a document for a thread
     */
    private Document createDocument(Thread thread){
        Document doc = new Document();
        doc.add(Field.Text("title", thread.getTitle()));
        doc.add(Field.Text("content", thread.getContent()));
        doc.add(Field.Text("author", thread.getAuthor()));
        doc.add(Field.Text("timestamp", thread.getTimeStamp()));
        String category = DAOFactory.getInstance().getForumDAO().getForum(thread.getCategory()).getName();
        doc.add(Field.Text("category", category));
        doc.add(Field.Text("categoryID", "" + thread.getCategory()));
        long parentID = thread.getID();
        if (thread.getParentID() != -1){
            parentID = thread.getParentID();
        }
        doc.add(Field.Text("parentID", "" + parentID));
        return doc;
    }

    /**
     * Program entry point
     *
     * @param args[0]   the directory index is to be built
     */
    public static void main( String args[] ){
        String indexDir = args[0] + ForumConstants.INDEX_DIR;

        initDAOFactory();

        try{
            IndexBuilder builder = new IndexBuilder( indexDir );
            builder.buildIndex();
        }catch (SQLException sqle){
			sqle.printStackTrace();
        }catch (IOException ioe){
			ioe.printStackTrace();
        }
    }

    private static void initDAOFactory() {
        try {
            new MysqlFixture().setUp();
            DAOFactory.getInstance().buildForumDAO("web-inf/forums.xml");
        } catch (Exception e) {
            e.printStackTrace();  //To change body of catch statement use Options | File Templates.
        }
    }

}