AbstractAggregationFunction.java

/* Copyright 2012 Thorben Lindhauer
 * 
 * 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 de.unipotsdam.hpi.thorben.ppi.measure.process;

import java.util.List;

import org.activiti.engine.ActivitiException;

import de.unipotsdam.hpi.thorben.ppi.measure.instance.entity.BaseMeasureInstance;
import de.unipotsdam.hpi.thorben.ppi.typehelper.TypeHelper;

public abstract class AbstractAggregationFunction<T extends Number, K extends BaseMeasureInstance>
		implements AggregationFunction<T, K> {

	protected TypeHelper<T> helper;
	
	public AbstractAggregationFunction(TypeHelper<T> typeHelper) {
		this.helper = typeHelper;
	}
	
	public T calculate(List<K> baseMeasureValues) {
		if (baseMeasureValues == null || baseMeasureValues.isEmpty()) {
			throw new ActivitiException("Cannot calculate aggregation function: No BaseMeasure values were supplied");
		}
		return performCalculation(baseMeasureValues);
	}
	
	protected abstract T performCalculation(List<K> baseMeasureValues);
}