| /* |
| * 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.tinkerpop.gremlin.process.traversal.step.map; |
| |
| import org.apache.tinkerpop.gremlin.process.computer.KeyValue; |
| import org.apache.tinkerpop.gremlin.process.computer.MapReduce; |
| import org.apache.tinkerpop.gremlin.process.computer.traversal.TraversalVertexProgram; |
| import org.apache.tinkerpop.gremlin.process.computer.util.StaticMapReduce; |
| import org.apache.tinkerpop.gremlin.process.traversal.Traversal; |
| import org.apache.tinkerpop.gremlin.process.traversal.Traverser; |
| import org.apache.tinkerpop.gremlin.process.traversal.step.MapReducer; |
| import org.apache.tinkerpop.gremlin.process.traversal.step.util.ReducingBarrierStep; |
| import org.apache.tinkerpop.gremlin.process.traversal.traverser.TraverserRequirement; |
| import org.apache.tinkerpop.gremlin.structure.Vertex; |
| import org.apache.tinkerpop.gremlin.util.function.ConstantSupplier; |
| import org.apache.tinkerpop.gremlin.util.iterator.IteratorUtils; |
| |
| import java.io.Serializable; |
| import java.util.Collections; |
| import java.util.EnumSet; |
| import java.util.Iterator; |
| import java.util.Set; |
| import java.util.function.BiFunction; |
| |
| import static org.apache.tinkerpop.gremlin.process.traversal.NumberHelper.add; |
| import static org.apache.tinkerpop.gremlin.process.traversal.NumberHelper.mul; |
| |
| /** |
| * @author Marko A. Rodriguez (http://markorodriguez.com) |
| */ |
| public final class SumGlobalStep<S extends Number> extends ReducingBarrierStep<S, S> implements MapReducer { |
| |
| private static final Set<TraverserRequirement> REQUIREMENTS = EnumSet.of( |
| TraverserRequirement.BULK, |
| TraverserRequirement.OBJECT |
| ); |
| |
| public SumGlobalStep(final Traversal.Admin traversal) { |
| super(traversal); |
| this.setSeedSupplier(new ConstantSupplier<>((S) Integer.valueOf(0))); |
| this.setBiFunction(SumGlobalBiFunction.instance()); |
| } |
| |
| |
| @Override |
| public Set<TraverserRequirement> getRequirements() { |
| return REQUIREMENTS; |
| } |
| |
| @Override |
| public MapReduce<MapReduce.NullObject, Number, MapReduce.NullObject, Number, Number> getMapReduce() { |
| return SumGlobalMapReduce.instance(); |
| } |
| |
| ///// |
| |
| private static class SumGlobalBiFunction<S extends Number> implements BiFunction<S, Traverser<S>, S>, Serializable { |
| |
| private static final SumGlobalBiFunction INSTANCE = new SumGlobalBiFunction<>(); |
| |
| private SumGlobalBiFunction() { |
| |
| } |
| |
| @Override |
| public S apply(final S mutatingSeed, final Traverser<S> traverser) { |
| return (S) add(mutatingSeed, mul(traverser.get(), traverser.bulk())); |
| } |
| |
| public static <S extends Number> SumGlobalBiFunction<S> instance() { |
| return INSTANCE; |
| } |
| } |
| |
| /////////// |
| |
| private static class SumGlobalMapReduce extends StaticMapReduce<MapReduce.NullObject, Number, MapReduce.NullObject, Number, Number> { |
| |
| private static final SumGlobalMapReduce INSTANCE = new SumGlobalMapReduce(); |
| |
| private SumGlobalMapReduce() { |
| |
| } |
| |
| @Override |
| public boolean doStage(final MapReduce.Stage stage) { |
| return true; |
| } |
| |
| @Override |
| public void map(final Vertex vertex, final MapEmitter<NullObject, Number> emitter) { |
| final Iterator<Number> values = IteratorUtils.map(vertex.<Set<Traverser.Admin<Number>>>property(TraversalVertexProgram.HALTED_TRAVERSERS).orElse(Collections.emptySet()).iterator(), |
| traverser -> mul(traverser.get(), traverser.bulk())); |
| if (values.hasNext()) |
| emitter.emit(getSum(values)); |
| } |
| |
| @Override |
| public void combine(final NullObject key, final Iterator<Number> values, final ReduceEmitter<NullObject, Number> emitter) { |
| this.reduce(key, values, emitter); |
| } |
| |
| @Override |
| public void reduce(final NullObject key, final Iterator<Number> values, final ReduceEmitter<NullObject, Number> emitter) { |
| if (values.hasNext()) |
| emitter.emit(getSum(values)); |
| } |
| |
| private Number getSum(final Iterator<Number> numbers) { |
| Number sum = numbers.next(); |
| while (numbers.hasNext()) { |
| sum = add(sum, numbers.next()); |
| } |
| return sum; |
| } |
| |
| @Override |
| public String getMemoryKey() { |
| return REDUCING; |
| } |
| |
| @Override |
| public Number generateFinalResult(final Iterator<KeyValue<NullObject, Number>> keyValues) { |
| return keyValues.hasNext() ? keyValues.next().getValue() : 0; |
| } |
| |
| public static SumGlobalMapReduce instance() { |
| return INSTANCE; |
| } |
| } |
| } |