Java HaltedTraverserStrategy类代码示例

import org.apache.tinkerpop.gremlin.process.traversal.strategy.decoration.HaltedTraverserStrategy; //导入依赖的package包/类
@Test
public void shouldReturnDetachedElements() {
    final Graph graph = TinkerFactory.createModern();
    final GraphTraversalSource g = graph.traversal().withComputer().withStrategies(HaltedTraverserStrategy.create(new MapConfiguration(new HashMap<String, Object>() {{
        put(HaltedTraverserStrategy.HALTED_TRAVERSER_FACTORY, DetachedFactory.class.getCanonicalName());
    }})));
    g.V().out().forEachRemaining(vertex -> assertEquals(DetachedVertex.class, vertex.getClass()));
    g.V().out().properties("name").forEachRemaining(vertexProperty -> assertEquals(DetachedVertexProperty.class, vertexProperty.getClass()));
    g.V().out().values("name").forEachRemaining(value -> assertEquals(String.class, value.getClass()));
    g.V().out().outE().forEachRemaining(edge -> assertEquals(DetachedEdge.class, edge.getClass()));
    g.V().out().outE().properties("weight").forEachRemaining(property -> assertEquals(DetachedProperty.class, property.getClass()));
    g.V().out().outE().values("weight").forEachRemaining(value -> assertEquals(Double.class, value.getClass()));
    g.V().out().out().forEachRemaining(vertex -> assertEquals(DetachedVertex.class, vertex.getClass()));
    g.V().out().out().path().forEachRemaining(path -> assertEquals(DetachedPath.class, path.getClass()));
    g.V().out().pageRank().forEachRemaining(vertex -> assertEquals(DetachedVertex.class, vertex.getClass()));
    g.V().out().pageRank().out().forEachRemaining(vertex -> assertEquals(DetachedVertex.class, vertex.getClass()));
    // should handle nested collections
    g.V().out().fold().next().forEach(vertex -> assertEquals(DetachedVertex.class, vertex.getClass()));
}
 

import org.apache.tinkerpop.gremlin.process.traversal.strategy.decoration.HaltedTraverserStrategy; //导入依赖的package包/类
@Test
public void shouldReturnReferenceElements() {
    final Graph graph = TinkerFactory.createModern();
    GraphTraversalSource g = graph.traversal().withComputer().withStrategies(HaltedTraverserStrategy.reference());
    g.V().out().forEachRemaining(vertex -> assertEquals(ReferenceVertex.class, vertex.getClass()));
    g.V().out().properties("name").forEachRemaining(vertexProperty -> assertEquals(ReferenceVertexProperty.class, vertexProperty.getClass()));
    g.V().out().values("name").forEachRemaining(value -> assertEquals(String.class, value.getClass()));
    g.V().out().outE().forEachRemaining(edge -> assertEquals(ReferenceEdge.class, edge.getClass()));
    g.V().out().outE().properties("weight").forEachRemaining(property -> assertEquals(ReferenceProperty.class, property.getClass()));
    g.V().out().outE().values("weight").forEachRemaining(value -> assertEquals(Double.class, value.getClass()));
    g.V().out().out().forEachRemaining(vertex -> assertEquals(ReferenceVertex.class, vertex.getClass()));
    g.V().out().out().path().forEachRemaining(path -> assertEquals(ReferencePath.class, path.getClass()));
    g.V().out().pageRank().forEachRemaining(vertex -> assertEquals(ReferenceVertex.class, vertex.getClass()));
    g.V().out().pageRank().out().forEachRemaining(vertex -> assertEquals(ReferenceVertex.class, vertex.getClass()));
    // the default should be reference elements
    g = graph.traversal().withComputer();
    g.V().out().forEachRemaining(vertex -> assertEquals(ReferenceVertex.class, vertex.getClass()));
    g.V().out().properties("name").forEachRemaining(vertexProperty -> assertEquals(ReferenceVertexProperty.class, vertexProperty.getClass()));
    g.V().out().values("name").forEachRemaining(value -> assertEquals(String.class, value.getClass()));
    g.V().out().outE().forEachRemaining(edge -> assertEquals(ReferenceEdge.class, edge.getClass()));
    g.V().out().outE().properties("weight").forEachRemaining(property -> assertEquals(ReferenceProperty.class, property.getClass()));
    g.V().out().outE().values("weight").forEachRemaining(value -> assertEquals(Double.class, value.getClass()));
    g.V().out().out().forEachRemaining(vertex -> assertEquals(ReferenceVertex.class, vertex.getClass()));
    g.V().out().out().path().forEachRemaining(path -> assertEquals(ReferencePath.class, path.getClass()));
    g.V().out().pageRank().forEachRemaining(vertex -> assertEquals(ReferenceVertex.class, vertex.getClass()));
    g.V().out().pageRank().out().forEachRemaining(vertex -> assertEquals(ReferenceVertex.class, vertex.getClass()));
    // should handle nested collections
    g.V().out().fold().next().forEach(vertex -> assertEquals(ReferenceVertex.class, vertex.getClass()));
}
 

import org.apache.tinkerpop.gremlin.process.traversal.strategy.decoration.HaltedTraverserStrategy; //导入依赖的package包/类
public DetachingIterator(final Traversal.Admin<?, E> traversal) {
    this.inner = traversal.getEndStep();
    this.haltedTraverserStrategy = (HaltedTraverserStrategy) traversal.getStrategies().toList().stream().filter(s -> s instanceof HaltedTraverserStrategy).findAny().orElse(
            Boolean.valueOf(System.getProperty("is.testing", "false")) ?
                    HaltedTraverserStrategy.detached() :
                    HaltedTraverserStrategy.reference());
}
 

import org.apache.tinkerpop.gremlin.process.traversal.strategy.decoration.HaltedTraverserStrategy; //导入依赖的package包/类
@Test
public void shouldReturnDetachedElements() {
    final Graph graph = TinkerFactory.createModern();
    final GraphTraversalSource g = graph.traversal().withComputer().withStrategies(HaltedTraverserStrategy.detached());
    g.V().out().forEachRemaining(vertex -> assertEquals(DetachedVertex.class, vertex.getClass()));
    g.V().out().properties("name").forEachRemaining(vertexProperty -> assertEquals(DetachedVertexProperty.class, vertexProperty.getClass()));
    g.V().out().values("name").forEachRemaining(value -> assertEquals(String.class, value.getClass()));
    g.V().out().outE().forEachRemaining(edge -> assertEquals(DetachedEdge.class, edge.getClass()));
    g.V().out().outE().properties("weight").forEachRemaining(property -> assertEquals(DetachedProperty.class, property.getClass()));
    g.V().out().outE().values("weight").forEachRemaining(value -> assertEquals(Double.class, value.getClass()));
    g.V().out().out().forEachRemaining(vertex -> assertEquals(DetachedVertex.class, vertex.getClass()));
    g.V().out().out().path().forEachRemaining(path -> assertEquals(DetachedPath.class, path.getClass()));
    g.V().out().pageRank().forEachRemaining(vertex -> assertEquals(DetachedVertex.class, vertex.getClass()));
    g.V().out().pageRank().out().forEachRemaining(vertex -> assertEquals(DetachedVertex.class, vertex.getClass()));
}
 

import org.apache.tinkerpop.gremlin.process.traversal.strategy.decoration.HaltedTraverserStrategy; //导入依赖的package包/类
@Test
public void shouldReturnReferenceElements() {
    final Graph graph = TinkerFactory.createModern();
    GraphTraversalSource g = graph.traversal().withComputer().withStrategies(HaltedTraverserStrategy.reference());
    g.V().out().forEachRemaining(vertex -> assertEquals(ReferenceVertex.class, vertex.getClass()));
    g.V().out().properties("name").forEachRemaining(vertexProperty -> assertEquals(ReferenceVertexProperty.class, vertexProperty.getClass()));
    g.V().out().values("name").forEachRemaining(value -> assertEquals(String.class, value.getClass()));
    g.V().out().outE().forEachRemaining(edge -> assertEquals(ReferenceEdge.class, edge.getClass()));
    g.V().out().outE().properties("weight").forEachRemaining(property -> assertEquals(ReferenceProperty.class, property.getClass()));
    g.V().out().outE().values("weight").forEachRemaining(value -> assertEquals(Double.class, value.getClass()));
    g.V().out().out().forEachRemaining(vertex -> assertEquals(ReferenceVertex.class, vertex.getClass()));
    g.V().out().out().path().forEachRemaining(path -> assertEquals(ReferencePath.class, path.getClass()));
    g.V().out().pageRank().forEachRemaining(vertex -> assertEquals(ReferenceVertex.class, vertex.getClass()));
    g.V().out().pageRank().out().forEachRemaining(vertex -> assertEquals(ReferenceVertex.class, vertex.getClass()));
    // the default should be reference elements
    g = graph.traversal().withComputer();
    g.V().out().forEachRemaining(vertex -> assertEquals(ReferenceVertex.class, vertex.getClass()));
    g.V().out().properties("name").forEachRemaining(vertexProperty -> assertEquals(ReferenceVertexProperty.class, vertexProperty.getClass()));
    g.V().out().values("name").forEachRemaining(value -> assertEquals(String.class, value.getClass()));
    g.V().out().outE().forEachRemaining(edge -> assertEquals(ReferenceEdge.class, edge.getClass()));
    g.V().out().outE().properties("weight").forEachRemaining(property -> assertEquals(ReferenceProperty.class, property.getClass()));
    g.V().out().outE().values("weight").forEachRemaining(value -> assertEquals(Double.class, value.getClass()));
    g.V().out().out().forEachRemaining(vertex -> assertEquals(ReferenceVertex.class, vertex.getClass()));
    g.V().out().out().path().forEachRemaining(path -> assertEquals(ReferencePath.class, path.getClass()));
    g.V().out().pageRank().forEachRemaining(vertex -> assertEquals(ReferenceVertex.class, vertex.getClass()));
    g.V().out().pageRank().out().forEachRemaining(vertex -> assertEquals(ReferenceVertex.class, vertex.getClass()));
}
 

import org.apache.tinkerpop.gremlin.process.traversal.strategy.decoration.HaltedTraverserStrategy; //导入依赖的package包/类
public TraverserIterator(final Traversal.Admin traversal) {
    this.traversal = traversal;
    this.barrierSize = traversal.getTraverserRequirements().contains(TraverserRequirement.ONE_BULK) ? 1 : 1000;
    this.haltedTraverserStrategy = traversal.getStrategies().getStrategy(HaltedTraverserStrategy.class).orElse(
            Boolean.valueOf(System.getProperty("is.testing", "false")) ?
                    HaltedTraverserStrategy.detached() :
                    HaltedTraverserStrategy.reference());
}
 

import org.apache.tinkerpop.gremlin.process.traversal.strategy.decoration.HaltedTraverserStrategy; //导入依赖的package包/类
@Override
public void loadState(final Graph graph, final Configuration configuration) {
    if (!configuration.containsKey(TRAVERSAL))
        throw new IllegalArgumentException("The configuration does not have a traversal: " + TRAVERSAL);
    this.traversal = PureTraversal.loadState(configuration, TRAVERSAL, graph);
    if (!this.traversal.get().isLocked())
        this.traversal.get().applyStrategies();
    /// traversal is compiled and ready to be introspected
    this.traversalMatrix = new TraversalMatrix<>(this.traversal.get());
    // get any master-traversal halted traversers
    this.haltedTraversers = TraversalVertexProgram.loadHaltedTraversers(configuration);
    // if results will be serialized out, don't save halted traversers across the cluster
    this.returnHaltedTraversers =
            (this.traversal.get().getParent().asStep().getNextStep() instanceof ComputerResultStep || // if its just going to stream it out, don't distribute
                    this.traversal.get().getParent().asStep().getNextStep() instanceof EmptyStep ||  // same as above, but if using TraversalVertexProgramStep directly
                    (this.traversal.get().getParent().asStep().getNextStep() instanceof ProfileStep && // same as above, but needed for profiling
                            this.traversal.get().getParent().asStep().getNextStep().getNextStep() instanceof ComputerResultStep));
    // determine how to store halted traversers
    this.haltedTraverserStrategy = ((HaltedTraverserStrategy) this.traversal.get().getStrategies().toList()
            .stream()
            .filter(strategy -> strategy instanceof HaltedTraverserStrategy)
            .findAny()
            .orElse(HaltedTraverserStrategy.reference()));
    // register traversal side-effects in memory
    this.memoryComputeKeys.addAll(MemoryTraversalSideEffects.getMemoryComputeKeys(this.traversal.get()));
    // register MapReducer memory compute keys
    for (final MapReducer<?, ?, ?, ?, ?> mapReducer : TraversalHelper.getStepsOfAssignableClassRecursively(MapReducer.class, this.traversal.get())) {
        this.mapReducers.add(mapReducer.getMapReduce());
        this.memoryComputeKeys.add(MemoryComputeKey.of(mapReducer.getMapReduce().getMemoryKey(), Operator.assign, false, false));
    }
    // register memory computing steps that use memory compute keys
    for (final MemoryComputing<?> memoryComputing : TraversalHelper.getStepsOfAssignableClassRecursively(MemoryComputing.class, this.traversal.get())) {
        this.memoryComputeKeys.add(memoryComputing.getMemoryComputeKey());
    }
    // register profile steps (TODO: try to hide this)
    for (final ProfileStep profileStep : TraversalHelper.getStepsOfAssignableClassRecursively(ProfileStep.class, this.traversal.get())) {
        this.traversal.get().getSideEffects().register(profileStep.getId(), new MutableMetricsSupplier(profileStep.getPreviousStep()), ProfileStep.ProfileBiOperator.instance());
    }
    // register TraversalVertexProgram specific memory compute keys
    this.memoryComputeKeys.add(MemoryComputeKey.of(VOTE_TO_HALT, Operator.and, false, true));
    this.memoryComputeKeys.add(MemoryComputeKey.of(HALTED_TRAVERSERS, Operator.addAll, false, false));
    this.memoryComputeKeys.add(MemoryComputeKey.of(ACTIVE_TRAVERSERS, Operator.addAll, true, true));
    this.memoryComputeKeys.add(MemoryComputeKey.of(MUTATED_MEMORY_KEYS, Operator.addAll, false, true));
    this.memoryComputeKeys.add(MemoryComputeKey.of(COMPLETED_BARRIERS, Operator.addAll, true, true));
}
 

import org.apache.tinkerpop.gremlin.process.traversal.strategy.decoration.HaltedTraverserStrategy; //导入依赖的package包/类
protected static void processTraversers(final PureTraversal<?, ?> traversal,
                                        final TraversalMatrix<?, ?> traversalMatrix,
                                        TraverserSet<Object> toProcessTraversers,
                                        final TraverserSet<Object> remoteActiveTraversers,
                                        final TraverserSet<Object> haltedTraversers,
                                        final HaltedTraverserStrategy haltedTraverserStrategy) {

    while (!toProcessTraversers.isEmpty()) {
        final TraverserSet<Object> localActiveTraversers = new TraverserSet<>();
        Step<Object, Object> previousStep = EmptyStep.instance();
        Step<Object, Object> currentStep = EmptyStep.instance();

        // these are traversers that are at the master traversal and will either halt here or be distributed back to the workers as needed
        final Iterator<Traverser.Admin<Object>> traversers = toProcessTraversers.iterator();
        while (traversers.hasNext()) {
            final Traverser.Admin<Object> traverser = traversers.next();
            traversers.remove();
            traverser.set(DetachedFactory.detach(traverser.get(), true)); // why?
            traverser.setSideEffects(traversal.get().getSideEffects());
            if (traverser.isHalted())
                haltedTraversers.add(haltedTraverserStrategy.halt(traverser));
            else if (isRemoteTraverser(traverser, traversalMatrix))  // this is so that patterns like order().name work as expected. try and stay local as long as possible
                remoteActiveTraversers.add(traverser.detach());
            else {
                currentStep = traversalMatrix.getStepById(traverser.getStepId());
                if (!currentStep.getId().equals(previousStep.getId()) && !(previousStep instanceof EmptyStep)) {
                    while (previousStep.hasNext()) {
                        final Traverser.Admin<Object> result = previousStep.next();
                        if (result.isHalted())
                            haltedTraversers.add(haltedTraverserStrategy.halt(result));
                        else if (isRemoteTraverser(result, traversalMatrix))
                            remoteActiveTraversers.add(result.detach());
                        else
                            localActiveTraversers.add(result);
                    }
                }
                currentStep.addStart(traverser);
                previousStep = currentStep;
            }
        }
        if (!(currentStep instanceof EmptyStep)) {
            while (currentStep.hasNext()) {
                final Traverser.Admin<Object> traverser = currentStep.next();
                if (traverser.isHalted())
                    haltedTraversers.add(haltedTraverserStrategy.halt(traverser));
                else if (isRemoteTraverser(traverser, traversalMatrix))
                    remoteActiveTraversers.add(traverser.detach());
                else
                    localActiveTraversers.add(traverser);
            }
        }
        assert toProcessTraversers.isEmpty();
        toProcessTraversers = localActiveTraversers;
    }
}
 

import org.apache.tinkerpop.gremlin.process.traversal.strategy.decoration.HaltedTraverserStrategy; //导入依赖的package包/类
@Override
public void loadState(final Graph graph, final Configuration configuration) {
    if (!configuration.containsKey(TRAVERSAL))
        throw new IllegalArgumentException("The configuration does not have a traversal: " + TRAVERSAL);
    this.traversal = PureTraversal.loadState(configuration, TRAVERSAL, graph);
    if (!this.traversal.get().isLocked())
        this.traversal.get().applyStrategies();
    /// traversal is compiled and ready to be introspected
    this.traversalMatrix = new TraversalMatrix<>(this.traversal.get());
    // get any master-traversal halted traversers
    this.haltedTraversers = TraversalVertexProgram.loadHaltedTraversers(configuration);
    // if results will be serialized out, don't save halted traversers across the cluster
    this.returnHaltedTraversers =
            (this.traversal.get().getParent().asStep().getNextStep() instanceof ComputerResultStep || // if its just going to stream it out, don't distribute
                    this.traversal.get().getParent().asStep().getNextStep() instanceof EmptyStep ||  // same as above, but if using TraversalVertexProgramStep directly
                    (this.traversal.get().getParent().asStep().getNextStep() instanceof ProfileStep && // same as above, but needed for profiling
                            this.traversal.get().getParent().asStep().getNextStep().getNextStep() instanceof ComputerResultStep));
    // determine how to store halted traversers
    this.haltedTraverserStrategy = ((HaltedTraverserStrategy) this.traversal.get().getStrategies().toList()
            .stream()
            .filter(strategy -> strategy instanceof HaltedTraverserStrategy)
            .findAny()
            .orElse(HaltedTraverserStrategy.reference()));
    // register traversal side-effects in memory
    this.memoryComputeKeys.addAll(MemoryTraversalSideEffects.getMemoryComputeKeys(this.traversal.get()));
    // register MapReducer memory compute keys
    for (final MapReducer<?, ?, ?, ?, ?> mapReducer : TraversalHelper.getStepsOfAssignableClassRecursively(MapReducer.class, this.traversal.get())) {
        this.mapReducers.add(mapReducer.getMapReduce());
        this.memoryComputeKeys.add(MemoryComputeKey.of(mapReducer.getMapReduce().getMemoryKey(), Operator.assign, false, false));
    }
    // register memory computing steps that use memory compute keys
    for (final MemoryComputing<?> memoryComputing : TraversalHelper.getStepsOfAssignableClassRecursively(MemoryComputing.class, this.traversal.get())) {
        this.memoryComputeKeys.add(memoryComputing.getMemoryComputeKey());
    }
    // register profile steps (TODO: try to hide this)
    for (final ProfileStep profileStep : TraversalHelper.getStepsOfAssignableClassRecursively(ProfileStep.class, this.traversal.get())) {
        this.traversal.get().getSideEffects().register(profileStep.getId(), new MutableMetricsSupplier(profileStep.getPreviousStep()), ProfileStep.ProfileBiOperator.instance());
    }
    // register TraversalVertexProgram specific memory compute keys
    this.memoryComputeKeys.add(MemoryComputeKey.of(VOTE_TO_HALT, Operator.and, false, true));
    this.memoryComputeKeys.add(MemoryComputeKey.of(HALTED_TRAVERSERS, Operator.addAll, false, false));
    this.memoryComputeKeys.add(MemoryComputeKey.of(ACTIVE_TRAVERSERS, Operator.addAll, true, true));
    this.memoryComputeKeys.add(MemoryComputeKey.of(MUTATED_MEMORY_KEYS, Operator.addAll, false, true));
    this.memoryComputeKeys.add(MemoryComputeKey.of(COMPLETED_BARRIERS, Operator.addAll, true, true));

    // does the traversal need profile information
    this.profile = !TraversalHelper.getStepsOfAssignableClassRecursively(ProfileStep.class, this.traversal.get()).isEmpty();
}
 

import org.apache.tinkerpop.gremlin.process.traversal.strategy.decoration.HaltedTraverserStrategy; //导入依赖的package包/类
protected static void processTraversers(final PureTraversal<?, ?> traversal,
                                        final TraversalMatrix<?, ?> traversalMatrix,
                                        TraverserSet<Object> toProcessTraversers,
                                        final TraverserSet<Object> remoteActiveTraversers,
                                        final TraverserSet<Object> haltedTraversers,
                                        final HaltedTraverserStrategy haltedTraverserStrategy) {

    while (!toProcessTraversers.isEmpty()) {
        final TraverserSet<Object> localActiveTraversers = new TraverserSet<>();
        Step<Object, Object> previousStep = EmptyStep.instance();
        Step<Object, Object> currentStep = EmptyStep.instance();

        // these are traversers that are at the master traversal and will either halt here or be distributed back to the workers as needed
        final Iterator<Traverser.Admin<Object>> traversers = toProcessTraversers.iterator();
        while (traversers.hasNext()) {
            final Traverser.Admin<Object> traverser = traversers.next();
            traversers.remove();
            traverser.set(DetachedFactory.detach(traverser.get(), true)); // why?
            traverser.setSideEffects(traversal.get().getSideEffects());
            if (traverser.isHalted())
                haltedTraversers.add(haltedTraverserStrategy.halt(traverser));
            else if (isRemoteTraverser(traverser, traversalMatrix))  // this is so that patterns like order().name work as expected. try and stay local as long as possible
                remoteActiveTraversers.add(traverser.detach());
            else {
                currentStep = traversalMatrix.getStepById(traverser.getStepId());
                if (!currentStep.getId().equals(previousStep.getId()) && !(previousStep instanceof EmptyStep)) {
                    GraphComputing.atMaster(previousStep, true);
                    while (previousStep.hasNext()) {
                        final Traverser.Admin<Object> result = previousStep.next();
                        if (result.isHalted())
                            haltedTraversers.add(haltedTraverserStrategy.halt(result));
                        else if (isRemoteTraverser(result, traversalMatrix))
                            remoteActiveTraversers.add(result.detach());
                        else
                            localActiveTraversers.add(result);
                    }
                }
                currentStep.addStart(traverser);
                previousStep = currentStep;
            }
        }
        if (!(currentStep instanceof EmptyStep)) {
            GraphComputing.atMaster(currentStep, true);
            while (currentStep.hasNext()) {
                final Traverser.Admin<Object> traverser = currentStep.next();
                if (traverser.isHalted())
                    haltedTraversers.add(haltedTraverserStrategy.halt(traverser));
                else if (isRemoteTraverser(traverser, traversalMatrix))
                    remoteActiveTraversers.add(traverser.detach());
                else
                    localActiveTraversers.add(traverser);
            }
        }
        assert toProcessTraversers.isEmpty();
        toProcessTraversers = localActiveTraversers;
    }
}