Count.java example

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/*
 * 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 count of the non distinct rows for replicated & PR based queries.
 * 
 *
 */
public class Count implements Aggregator {
  private int count = 0;

  @Override
  public void accumulate(Object value) {
    if (value != null && value != QueryService.UNDEFINED) {
      ++this.count;
    }
  }

  @Override
  public void init() {

  }

  @Override
  public Object terminate() {
    return Integer.valueOf(count);
  }

}