/*
* Copyright 2010 Bizosys Technologies Limited
*
* Licensed to the Bizosys Technologies Limited (Bizosys) under one
* or more contributor license agreements.  See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership.  The Bizosys licenses this file
* to you 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.bizosys.hsearch.dictionary;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;

import com.bizosys.oneline.ApplicationFault;
import com.bizosys.oneline.SystemFault;
import com.bizosys.oneline.services.batch.BatchTask;

/**
 * Loads the dictionry terms to memory in intervals.
 * It helps for fuzzy search and regex search.
 * @author karan
 */
public class DictionaryRefresh implements BatchTask {

	/**
	 * The job name
	 */
	private String jobName = "DictionaryRefresh";
	
	public String getJobName() {
		return this.jobName;
	}

	public void setJobName(String jobName) {
		this.jobName = jobName;
	}

	public Object process() throws ApplicationFault, SystemFault {
		DictionaryManager manager = DictionaryManager.getInstance(); 
		Map<String, Dictionary> dicts = manager.getCachedTenants();
		
		int extraCached =  dicts.size() - manager.maxCacheSize;
		if ( extraCached < 0) return true;
		
		List<Dictionary> lstDicts = new ArrayList<Dictionary>();
		Collections.sort(lstDicts, new DictionaryUsageComparator());
		
		/**
		 * Unload the unused pieces which have been loaded for some time.
		 */
		for ( int i=0; i< extraCached; i++) {
			Dictionary dict = lstDicts.get(i);
			dicts.remove(dict.tenant);
			dict.clean();
		}

		/**
		 * Refresh the rests
		 */
		for ( Dictionary aDict: dicts.values()) {
			aDict.buildTerms();
		}
		
		return true;
	}
}