| /* |
| * 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.remote.traversal.strategy.decoration; |
| |
| import org.apache.tinkerpop.gremlin.process.computer.traversal.strategy.decoration.VertexProgramStrategy; |
| import org.apache.tinkerpop.gremlin.process.remote.RemoteConnection; |
| import org.apache.tinkerpop.gremlin.process.remote.RemoteGraph; |
| import org.apache.tinkerpop.gremlin.process.remote.traversal.step.map.RemoteStep; |
| import org.apache.tinkerpop.gremlin.process.traversal.Traversal; |
| import org.apache.tinkerpop.gremlin.process.traversal.TraversalStrategy; |
| import org.apache.tinkerpop.gremlin.process.traversal.step.sideEffect.ProfileSideEffectStep; |
| 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.strategy.decoration.ConnectiveStrategy; |
| import org.apache.tinkerpop.gremlin.process.traversal.strategy.decoration.ElementIdStrategy; |
| import org.apache.tinkerpop.gremlin.process.traversal.strategy.decoration.EventStrategy; |
| import org.apache.tinkerpop.gremlin.process.traversal.strategy.decoration.HaltedTraverserStrategy; |
| import org.apache.tinkerpop.gremlin.process.traversal.strategy.decoration.PartitionStrategy; |
| import org.apache.tinkerpop.gremlin.process.traversal.strategy.decoration.RequirementsStrategy; |
| import org.apache.tinkerpop.gremlin.process.traversal.strategy.decoration.SackStrategy; |
| import org.apache.tinkerpop.gremlin.process.traversal.strategy.decoration.SideEffectStrategy; |
| import org.apache.tinkerpop.gremlin.process.traversal.strategy.decoration.SubgraphStrategy; |
| import org.apache.tinkerpop.gremlin.process.traversal.strategy.verification.VerificationException; |
| import org.apache.tinkerpop.gremlin.process.traversal.util.TraversalHelper; |
| import org.apache.tinkerpop.gremlin.structure.util.empty.EmptyGraph; |
| |
| import java.util.Arrays; |
| import java.util.Collections; |
| import java.util.HashSet; |
| import java.util.Optional; |
| import java.util.Set; |
| |
| /** |
| * Reconstructs a {@link Traversal} by appending a {@link RemoteStep} to its end. That step will submit the |
| * {@link Traversal} to a {@link RemoteConnection} instance which will typically send it to a remote server for |
| * execution and return results. |
| * |
| * @author Stephen Mallette (http://stephen.genoprime.com) |
| * @author Marko A. Rodriguez (http://markorodriguez.com) |
| */ |
| public final class RemoteStrategy extends AbstractTraversalStrategy<TraversalStrategy.DecorationStrategy> |
| implements TraversalStrategy.DecorationStrategy { |
| |
| private static final RemoteStrategy INSTANCE = new RemoteStrategy(); |
| private final Optional<RemoteConnection> remoteConnection; |
| |
| /** |
| * Should be applied before all {@link DecorationStrategy} instances. |
| */ |
| private static final Set<Class<? extends DecorationStrategy>> POSTS = new HashSet<Class<? extends DecorationStrategy>>() {{ |
| add(VertexProgramStrategy.class); |
| add(ConnectiveStrategy.class); |
| add(ElementIdStrategy.class); |
| add(EventStrategy.class); |
| add(HaltedTraverserStrategy.class); |
| add(PartitionStrategy.class); |
| add(RequirementsStrategy.class); |
| add(SackStrategy.class); |
| add(SideEffectStrategy.class); |
| add(SubgraphStrategy.class); |
| }}; |
| |
| private RemoteStrategy() { |
| remoteConnection = Optional.empty(); |
| } |
| |
| public RemoteStrategy(final RemoteConnection remoteConnection) { |
| this.remoteConnection = Optional.ofNullable(remoteConnection); |
| } |
| |
| /** |
| * @deprecated As of release 3.2.2, replaced by {@link #RemoteStrategy(RemoteConnection)} where this method should |
| * only be used by {@link RemoteGraph} for backward compatibility. |
| */ |
| @Deprecated |
| public static RemoteStrategy instance() { |
| return INSTANCE; |
| } |
| |
| @Override |
| public Set<Class<? extends DecorationStrategy>> applyPost() { |
| return POSTS; |
| } |
| |
| @Override |
| public void apply(final Traversal.Admin<?, ?> traversal) { |
| // this check for a remoteConnection is really only relevant for backward compatibility for RemoteGraph prior |
| // to the now preferred method of withRemote(). |
| if (!remoteConnection.isPresent()) { |
| if (!(traversal.getGraph().orElse(EmptyGraph.instance()) instanceof RemoteGraph)) |
| throw new IllegalStateException("RemoteStrategy expects a RemoteGraph instance attached to the Traversal"); |
| |
| final RemoteGraph remoteGraph = (RemoteGraph) traversal.getGraph().get(); |
| if (null == remoteGraph.getConnection()) |
| throw new IllegalStateException("RemoteStrategy expects the RemoteGraph instance to have a RemoteConnection"); |
| } |
| |
| if (!(traversal.getParent() instanceof EmptyStep)) |
| return; |
| |
| // remote step wraps the traversal and emits the results from the remote connection. |
| final RemoteStep<?, ?> remoteStep = new RemoteStep<>(traversal, |
| remoteConnection.orElseGet(() -> ((RemoteGraph) traversal.getGraph().get()).getConnection())); |
| TraversalHelper.removeAllSteps(traversal); |
| traversal.addStep(remoteStep); |
| |
| // validations |
| assert traversal.getStartStep().equals(remoteStep); |
| assert traversal.getSteps().size() == 1; |
| assert traversal.getEndStep() == remoteStep; |
| } |
| } |