001/*
002 * Copyright (c) 2007-2022 The Cascading Authors. All Rights Reserved.
003 *
004 * Project and contact information: https://cascading.wensel.net/
005 *
006 * This file is part of the Cascading project.
007 *
008 * Licensed under the Apache License, Version 2.0 (the "License");
009 * you may not use this file except in compliance with the License.
010 * You may obtain a copy of the License at
011 *
012 *     http://www.apache.org/licenses/LICENSE-2.0
013 *
014 * Unless required by applicable law or agreed to in writing, software
015 * distributed under the License is distributed on an "AS IS" BASIS,
016 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
017 * See the License for the specific language governing permissions and
018 * limitations under the License.
019 */
020
021package cascading.nested.core.aggregate;
022
023import java.beans.ConstructorProperties;
024
025import cascading.tuple.Fields;
026import cascading.tuple.Tuple;
027import cascading.tuple.type.CoercibleType;
028
029/**
030 * Class SumLongNestedAggregate is a {@link cascading.nested.core.NestedAggregate} implementation for summing
031 * long values collected from the parent container object.
032 */
033public class SumLongNestedAggregate<Node> extends BaseNumberNestedAggregate<Node, Long, BaseNumberNestedAggregate.BaseContext<Long, Node>>
034  {
035  public static class Context<Node> extends BaseContext<Long, Node>
036    {
037    long sum = 0L;
038
039    public Context( SumLongNestedAggregate<Node> aggregateFunction, CoercibleType<Node> coercibleType )
040      {
041      super( aggregateFunction, coercibleType );
042      }
043
044    @Override
045    protected void aggregateFilteredValue( Long value )
046      {
047      if( value == null )
048        return;
049
050      sum += value;
051      }
052
053    @Override
054    protected void completeAggregateValue( Tuple results )
055      {
056      results.set( 0, sum );
057      }
058
059    @Override
060    public void reset()
061      {
062      sum = 0L;
063      super.reset();
064      }
065    }
066
067  @ConstructorProperties({"declaredFields"})
068  public SumLongNestedAggregate( Fields declaredFields )
069    {
070    super( declaredFields, Long.TYPE );
071    }
072
073  @Override
074  public Context<Node> createContext( CoercibleType<Node> nestedCoercibleType )
075    {
076    return new Context<>( this, nestedCoercibleType );
077    }
078  }