| /* |
| * 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.computer.traversal.strategy.decoration; |
| |
| import org.apache.tinkerpop.gremlin.process.computer.Computer; |
| import org.apache.tinkerpop.gremlin.process.computer.traversal.step.VertexComputing; |
| import org.apache.tinkerpop.gremlin.process.computer.traversal.step.map.ComputerResultStep; |
| import org.apache.tinkerpop.gremlin.process.computer.traversal.step.map.ProgramVertexProgramStep; |
| import org.apache.tinkerpop.gremlin.process.computer.traversal.step.map.TraversalVertexProgramStep; |
| import org.apache.tinkerpop.gremlin.process.remote.traversal.strategy.decoration.RemoteStrategy; |
| import org.apache.tinkerpop.gremlin.process.traversal.Step; |
| import org.apache.tinkerpop.gremlin.process.traversal.Traversal; |
| import org.apache.tinkerpop.gremlin.process.traversal.TraversalStrategies; |
| import org.apache.tinkerpop.gremlin.process.traversal.TraversalStrategy; |
| import org.apache.tinkerpop.gremlin.process.traversal.dsl.graph.__; |
| import org.apache.tinkerpop.gremlin.process.traversal.step.map.GraphStep; |
| import org.apache.tinkerpop.gremlin.process.traversal.step.util.EmptyStep; |
| import org.apache.tinkerpop.gremlin.process.traversal.strategy.AbstractTraversalStrategy; |
| import org.apache.tinkerpop.gremlin.process.traversal.util.DefaultTraversal; |
| import org.apache.tinkerpop.gremlin.process.traversal.util.TraversalHelper; |
| |
| import java.util.HashSet; |
| import java.util.Optional; |
| import java.util.Set; |
| |
| /** |
| * @author Marko A. Rodriguez (http://markorodriguez.com) |
| */ |
| public final class VertexProgramStrategy extends AbstractTraversalStrategy<TraversalStrategy.DecorationStrategy> implements TraversalStrategy.DecorationStrategy { |
| |
| private Computer computer; |
| |
| private VertexProgramStrategy() { |
| |
| } |
| |
| public VertexProgramStrategy(final Computer computer) { |
| this.computer = computer; |
| } |
| |
| @Override |
| public void apply(final Traversal.Admin<?, ?> traversal) { |
| // VertexPrograms can only execute at the root level of a Traversal and should not be applied locally prior to RemoteStrategy |
| if (!(traversal.getParent() instanceof EmptyStep) || traversal.getStrategies().toList().contains(RemoteStrategy.instance())) |
| return; |
| |
| // back propagate as()-labels off of vertex computing steps |
| Step<?, ?> currentStep = traversal.getEndStep(); |
| final Set<String> currentLabels = new HashSet<>(); |
| while (!(currentStep instanceof EmptyStep)) { |
| if (currentStep instanceof VertexComputing && !(currentStep instanceof ProgramVertexProgramStep)) { // todo: is there a general solution? |
| currentLabels.addAll(currentStep.getLabels()); |
| currentStep.getLabels().forEach(currentStep::removeLabel); |
| } else { |
| currentLabels.forEach(currentStep::addLabel); |
| currentLabels.clear(); |
| } |
| currentStep = currentStep.getPreviousStep(); |
| } |
| |
| // push GraphStep forward in the chain to reduce the number of TraversalVertexProgram compilations |
| currentStep = traversal.getStartStep(); |
| while (!(currentStep instanceof EmptyStep)) { |
| if (currentStep instanceof GraphStep && currentStep.getNextStep() instanceof VertexComputing) { |
| int index = TraversalHelper.stepIndex(currentStep.getNextStep(), traversal); |
| traversal.removeStep(currentStep); |
| traversal.addStep(index, currentStep); |
| } else |
| currentStep = currentStep.getNextStep(); |
| } |
| |
| // wrap all non-VertexComputing steps into a TraversalVertexProgramStep |
| currentStep = traversal.getStartStep(); |
| while (!(currentStep instanceof EmptyStep)) { |
| Traversal.Admin<?, ?> computerTraversal = new DefaultTraversal<>(); |
| Step<?, ?> firstLegalOLAPStep = getFirstLegalOLAPStep(currentStep); |
| Step<?, ?> lastLegalOLAPStep = getLastLegalOLAPStep(currentStep); |
| if (!(firstLegalOLAPStep instanceof EmptyStep)) { |
| int index = TraversalHelper.stepIndex(firstLegalOLAPStep, traversal); |
| TraversalHelper.removeToTraversal(firstLegalOLAPStep, lastLegalOLAPStep.getNextStep(), (Traversal.Admin) computerTraversal); |
| final TraversalVertexProgramStep traversalVertexProgramStep = new TraversalVertexProgramStep(traversal, computerTraversal); |
| traversal.addStep(index, traversalVertexProgramStep); |
| } |
| currentStep = traversal.getStartStep(); |
| while (!(currentStep instanceof EmptyStep)) { |
| if (!(currentStep instanceof VertexComputing)) |
| break; |
| currentStep = currentStep.getNextStep(); |
| } |
| } |
| // if the last vertex computing step is a TraversalVertexProgramStep convert to OLTP with ComputerResultStep |
| TraversalHelper.getLastStepOfAssignableClass(VertexComputing.class, traversal).ifPresent(step -> { |
| if (step instanceof TraversalVertexProgramStep) { |
| final ComputerResultStep computerResultStep = new ComputerResultStep<>(traversal); |
| ((TraversalVertexProgramStep) step).getGlobalChildren().get(0).getEndStep().getLabels().forEach(computerResultStep::addLabel); |
| // labeling should happen in TraversalVertexProgram (perhaps MapReduce) |
| TraversalHelper.insertAfterStep(computerResultStep, (Step) step, traversal); |
| } |
| }); |
| // if there is a dangling vertex computing step, add an identity traversal (solve this in the future with a specialized MapReduce) |
| if (traversal.getEndStep() instanceof VertexComputing && !(traversal.getEndStep() instanceof TraversalVertexProgramStep)) { |
| final TraversalVertexProgramStep traversalVertexProgramStep = new TraversalVertexProgramStep(traversal, __.identity().asAdmin()); |
| traversal.addStep(traversalVertexProgramStep); |
| traversal.addStep(new ComputerResultStep<>(traversal)); |
| } |
| // all vertex computing steps needs the graph computer function |
| traversal.getSteps().stream().filter(step -> step instanceof VertexComputing).forEach(step -> ((VertexComputing) step).setComputer(this.computer)); |
| } |
| |
| private static Step<?, ?> getFirstLegalOLAPStep(Step<?, ?> currentStep) { |
| while (!(currentStep instanceof EmptyStep)) { |
| if (!(currentStep instanceof VertexComputing)) |
| return currentStep; |
| currentStep = currentStep.getNextStep(); |
| } |
| return EmptyStep.instance(); |
| } |
| |
| private static Step<?, ?> getLastLegalOLAPStep(Step<?, ?> currentStep) { |
| while (currentStep instanceof VertexComputing) |
| currentStep = currentStep.getNextStep(); |
| while (!(currentStep instanceof EmptyStep)) { |
| if (currentStep instanceof VertexComputing) |
| return currentStep.getPreviousStep(); |
| currentStep = currentStep.getNextStep(); |
| } |
| return EmptyStep.instance(); |
| } |
| |
| public static Optional<Computer> getComputer(final TraversalStrategies strategies) { |
| final Optional<TraversalStrategy<?>> optional = strategies.toList().stream().filter(strategy -> strategy instanceof VertexProgramStrategy).findAny(); |
| return optional.isPresent() ? Optional.of(((VertexProgramStrategy) optional.get()).computer) : Optional.empty(); |
| } |
| } |