com.github.javaclub.cdl.client.matrix.merger.aggregation.ComparableAggregationUnit Maven / Gradle / Ivy

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/**
 * Copyright 1999-2015 dangdang.com.
 * 
 * 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.github.javaclub.cdl.client.matrix.merger.aggregation;

import com.github.javaclub.cdl.client.matrix.merger.common.ResultSetUtil;

import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;

/**
 * 比较聚合单元.
 * 
 * @author gaohongtao
 */
@RequiredArgsConstructor
@Slf4j
public final class ComparableAggregationUnit extends AbstractAggregationUnit {
    
    private final boolean asc;
    
    private Comparable result;
    
    private final Class returnType;
    
    @SuppressWarnings("unchecked")
    @Override
    protected void doMerge(@SuppressWarnings("rawtypes") final Comparable... values) {
        if (null == values || null == values[0]) {
            return;
        }
        if (null == result) {
            result = values[0];
            log.trace("Comparable result: {}", result);
            return;
        }
        int comparedValue = values[0].compareTo(result);
        if (asc && comparedValue < 0 || !asc && comparedValue > 0) {
            result = values[0];
            log.trace("Comparable result: {}", result);
        }
    }
    
    @Override
    public Comparable getResult() {
    	return (Comparable) ResultSetUtil.convertValue(result, returnType);
    }
}