singleton一例

学习

package com.abc.def;

import java.io.IOException;
import org.apache.mahout.cf.taste.common.TasteException;
import org.apache.mahout.cf.taste.impl.model.jdbc.ReloadFromJDBCDataModel;
import org.apache.mahout.cf.taste.impl.neighborhood.NearestNUserNeighborhood;
import org.apache.mahout.cf.taste.impl.similarity.LogLikelihoodSimilarity;
import org.apache.mahout.cf.taste.model.DataModel;
import org.apache.mahout.cf.taste.model.JDBCDataModel;
import org.apache.mahout.cf.taste.neighborhood.UserNeighborhood;
import org.apache.mahout.cf.taste.similarity.UserSimilarity;

import com.ibm.taste.example.movie.recommender.BooleanMovieDataModel;

public final class MovieRecommenderSingleton {
	private final UserNeighborhood neighborhood;
	private static MovieRecommenderSingleton instance;
	private ReloadFromJDBCDataModel rfjdm;
	private ReloadFromJDBCIdImgurl rfjii;
	
	public ReloadFromJDBCIdImgurl getRfjii() {
		return rfjii;
	}

	public static synchronized MovieRecommenderSingleton getInstance()
	{
		return instance;
	}
	
	public static synchronized void initialize() throws TasteException, IOException
	{
		if( instance == null )
		{
			instance = new MovieRecommenderSingleton();
		}
	}
	
	private MovieRecommenderSingleton() throws TasteException, IOException
	{
		//reload from jdbc data model
		UserSimilarity userSimilarity;
		DataModel model = new BooleanMovieDataModel();
		rfjdm = new ReloadFromJDBCDataModel((JDBCDataModel) model);
		userSimilarity = new LogLikelihoodSimilarity(rfjdm);
		neighborhood = new NearestNUserNeighborhood(20, userSimilarity, rfjdm);
		
		//reload from jdbc id imgurl
		rfjii = new ReloadFromJDBCIdImgurl("192.168.3.84", "movie", "111111", "mymovie", "id_imgurl" );
	}

	/**
	 * @return the neighborhood
	 */
	public UserNeighborhood getNeighborhood() {
		return neighborhood;
	}
	
	public void refresh()
	{
		neighborhood.refresh( null );
		//rfjdm.refresh(null);
		
		rfjii.refresh();
	}
}