PersistenceDataModelFactory.java

/**
 * Copyright 2012 Anjuke Inc.
 *
 * 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 com.anjuke.romar.mahout.factory;

import java.io.File;

import org.apache.mahout.cf.taste.model.DataModel;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.anjuke.romar.core.RomarConfig;
import com.anjuke.romar.mahout.GenericReloadDataModel;
import com.anjuke.romar.mahout.PreferenceDataModel;
import com.anjuke.romar.mahout.persistence.FilePreferenceSource;
import com.anjuke.romar.mahout.persistence.PersistenceDataModelProxy;
import com.anjuke.romar.mahout.persistence.PreferenceSource;

public final class PersistenceDataModelFactory {
    private static final Logger log = LoggerFactory
            .getLogger(PersistenceDataModelFactory.class);

    private PersistenceDataModelFactory(){

    }

    private static PreferenceDataModel wrapDataModel(RomarConfig config,
            PreferenceDataModel dataModel) {
        final String persistencePath = config.getPersistencePath();
        if (persistencePath == null || persistencePath.isEmpty()) {
            return dataModel;
        }
        final PreferenceSource source = new FilePreferenceSource(
                new File(persistencePath));
        PreferenceDataModel model = new PersistenceDataModelProxy(dataModel, source);
        model.reload(null);

        Runtime.getRuntime().addShutdownHook(new Thread() {
            @Override
            public void run() {
                log.info("FilePreferenceSource on file " + persistencePath + " close");
                source.close();
            }
        });
        return model;
    }

    public static DataModel createDataModel(RomarConfig config) {
        DataModel dataModel = wrapDataModel(config, new GenericReloadDataModel());
        return dataModel;
    }
}