/*
 *  Copyright 2008 biaoping.yin
 *
 *  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.frameworkset.common.poolman.sql;

import com.fasterxml.uuid.EthernetAddress;
import com.fasterxml.uuid.Generators;
import com.fasterxml.uuid.impl.TimeBasedGenerator;



public class StrongUuidGenerator implements IdGenerator {

	 // different ProcessEngines on the same classloader share one generator.
	  protected static TimeBasedGenerator timeBasedGenerator;

	  public StrongUuidGenerator() {
	    ensureGeneratorInitialized();
	  }

	  protected void ensureGeneratorInitialized() {
	    if (timeBasedGenerator == null) {
	      synchronized (StrongUuidGenerator.class) {
	        if (timeBasedGenerator == null) {
	          timeBasedGenerator = Generators.timeBasedGenerator(EthernetAddress.fromInterface());
	        }
	      }
	    }
	  }

	  public String getNextId() {
	    return timeBasedGenerator.generate().toString();
	  }

}