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1   package org.apache.helix.alerts;
2   
3   /*
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   *   http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing,
15   * software distributed under the License is distributed on an
16   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17   * KIND, either express or implied.  See the License for the
18   * specific language governing permissions and limitations
19   * under the License.
20   */
21  
22  import java.util.ArrayList;
23  import java.util.Iterator;
24  import java.util.List;
25  
26  public class SumEachOperator extends Operator {
27  
28  	public SumEachOperator() {
29  		minInputTupleLists = 1;
30  		maxInputTupleLists = Integer.MAX_VALUE;
31  		inputOutputTupleListsCountsEqual = true;
32  		numOutputTupleLists = -1;
33  	}
34  
35  	//for each column, generate sum
36  	@Override
37  	public List<Iterator<Tuple<String>>> execute(List<Iterator<Tuple<String>>> input) {
38  		List<Iterator<Tuple<String>>> out = new ArrayList<Iterator<Tuple<String>>>();
39  		for (Iterator<Tuple<String>> currIt : input) {
40  			Tuple<String> currSum = null;
41  			while (currIt.hasNext()) {
42  				currSum = sumTuples(currSum, currIt.next());
43  			}
44  			ArrayList<Tuple<String>> currOutList = new ArrayList<Tuple<String>>();
45  			currOutList.add(currSum);
46  			out.add(currOutList.iterator());
47  		}
48  		return out;
49  	}
50  
51  }