/**                                                                                                                                                                                
 * Copyright (c) 2010 Yahoo! Inc. All rights reserved.                                                                                                                             
 *                                                                                                                                                                                 
 * 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. See accompanying                                                                                                                 
 * LICENSE file.                                                                                                                                                                   
 */

package com.yahoo.ycsb.generator;

/**
 * A generator that is capable of generating numeric values
 * 
 * @author cooperb
 *
 */
public abstract class NumberGenerator extends Generator<Number> 
{
	private Number lastVal;
	
	/**
	 * Set the last value generated. NumberGenerator subclasses must use this call
	 * to properly set the last value, or the {@link #lastValue()} calls won't work.
	 */
	protected void setLastValue(Number last)
	{
		lastVal=last;
	}
		
	
	@Override
	public Number lastValue()
	{
		return lastVal;
	}
	/**
	 * Return the expected value (mean) of the values this generator will return.
	 */
	public abstract double mean();
}
