| /* |
| * 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.strategy.decoration; |
| |
| import org.apache.tinkerpop.gremlin.process.computer.traversal.strategy.decoration.VertexProgramStrategy; |
| 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.step.util.EmptyStep; |
| import org.apache.tinkerpop.gremlin.process.traversal.step.util.RequirementsStep; |
| import org.apache.tinkerpop.gremlin.process.traversal.strategy.AbstractTraversalStrategy; |
| import org.apache.tinkerpop.gremlin.process.traversal.traverser.TraverserRequirement; |
| |
| import java.util.Collections; |
| import java.util.EnumSet; |
| import java.util.Set; |
| |
| /** |
| * @author Marko A. Rodriguez (http://markorodriguez.com) |
| */ |
| public final class RequirementsStrategy extends AbstractTraversalStrategy<TraversalStrategy.DecorationStrategy> implements TraversalStrategy.DecorationStrategy { |
| |
| private final Set<TraverserRequirement> requirements = EnumSet.noneOf(TraverserRequirement.class); |
| |
| private RequirementsStrategy() { |
| } |
| |
| @Override |
| public void apply(final Traversal.Admin<?, ?> traversal) { |
| if (traversal.getParent() instanceof EmptyStep && !this.requirements.isEmpty()) |
| traversal.addStep(new RequirementsStep<>(traversal, this.requirements)); |
| } |
| |
| public static void addRequirements(final TraversalStrategies traversalStrategies, final TraverserRequirement... requirements) { |
| RequirementsStrategy strategy = (RequirementsStrategy) traversalStrategies.toList().stream().filter(s -> s instanceof RequirementsStrategy).findAny().orElse(null); |
| if (null == strategy) { |
| strategy = new RequirementsStrategy(); |
| traversalStrategies.addStrategies(strategy); |
| } else { |
| final RequirementsStrategy cloneStrategy = new RequirementsStrategy(); |
| cloneStrategy.requirements.addAll(strategy.requirements); |
| strategy = cloneStrategy; |
| traversalStrategies.addStrategies(strategy); |
| } |
| Collections.addAll(strategy.requirements, requirements); |
| } |
| |
| @Override |
| public Set<Class<? extends DecorationStrategy>> applyPost() { |
| return Collections.singleton(VertexProgramStrategy.class); |
| } |
| } |