SetPreferenceServlet.java

/**
 * Copyright 2012 plista GmbH  (http://www.plista.com/)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and limitations under the License.
 */

package org.plista.kornakapi.web.servlets;

import org.apache.mahout.cf.taste.common.TasteException;
import org.plista.kornakapi.web.MissingParameterException;
import org.plista.kornakapi.web.Parameters;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import java.io.IOException;

/** servlet to add preferences */
public class SetPreferenceServlet extends BaseServlet {

  private static final Logger log = LoggerFactory.getLogger(SetPreferenceServlet.class);
  @Override
  protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    long userID = getParameterAsLong(request, Parameters.USER_ID, true);
    long itemID = getParameterAsLong(request, Parameters.ITEM_ID, true);
    float value = getParameterAsFloat(request, Parameters.VALUE, true);
    String label = null;
    try{
        label = getParameter(request, Parameters.LABEL, true);
    }catch(MissingParameterException e){
        if (log.isDebugEnabled()) {
            log.debug("Label Parameter is missing");
         }
    }

    if(userID < 0 || userID > 2147483647){
    	userID = this.idRemapping(userID);
    }
    if(itemID < 0 || itemID > 2147483647){
    	itemID = this.idRemapping(itemID);
    }
    if(label==null){
    	label = this.getDomainIndependetStorage().getItemsLabel(itemID);
        if (log.isDebugEnabled()) {
            log.debug("Fetched label {} from db for item {} ", label, itemID);
         }
    }
    this.getDomainIndependetStorage().setPreference(userID, itemID, value);  
    try{
    	preferenceChangeListener().notifyOfPreferenceChange(label);
    }catch(NullPointerException e){
        if (log.isInfoEnabled() && label!= null) {
            log.info("No recommender assigned for label {}", label);
         }
        if(label != null){
        	try {
    			createRecommenderForLabel(label);
    		} catch (TasteException te) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
        }

    }   	
      
  }

}