geode-core/src/main/java/org/apache/geode/cache/query/internal/aggregate/MaxMin.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more contributor license
 * agreements. See the NOTICE file distributed with this work for additional information regarding
 * copyright ownership. The ASF 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 org.apache.geode.cache.query.internal.aggregate;

import org.apache.geode.cache.query.Aggregator;
import org.apache.geode.cache.query.QueryService;

/**
 * Computes the Max or Min
 */
public class MaxMin implements Aggregator {
  private final boolean findMax;
  private Comparable currentOptima;

  Comparable getCurrentOptima() {
    return currentOptima;
  }

  public MaxMin(boolean findMax) {
    this.findMax = findMax;
  }

  @Override
  public void init() {}

  @Override
  public void accumulate(Object value) {
    if (value == null || value == QueryService.UNDEFINED) {
      return;
    }

    Comparable comparable = (Comparable) value;

    if (currentOptima == null) {
      currentOptima = comparable;
    } else {
      @SuppressWarnings("unchecked")
      int compare = currentOptima.compareTo(comparable);

      if (findMax) {
        currentOptima = compare < 0 ? comparable : currentOptima;
      } else {
        currentOptima = compare > 0 ? comparable : currentOptima;
      }
    }
  }

  @Override
  public Object terminate() {
    return currentOptima;
  }
}