| /* |
| * 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.verification; |
| |
| import org.apache.tinkerpop.gremlin.process.traversal.Step; |
| import org.apache.tinkerpop.gremlin.process.traversal.Traversal; |
| import org.apache.tinkerpop.gremlin.process.traversal.TraversalStrategy; |
| import org.apache.tinkerpop.gremlin.process.traversal.step.ComparatorHolder; |
| import org.apache.tinkerpop.gremlin.process.traversal.step.LambdaHolder; |
| import org.apache.tinkerpop.gremlin.process.traversal.strategy.AbstractTraversalStrategy; |
| |
| import java.util.Comparator; |
| |
| /** |
| * {@code LambdaRestrictionStrategy} does not allow lambdas to be used in a {@link Traversal}. The contents of a lambda |
| * cannot be analyzed/optimized and thus, reduces the ability of other {@link TraversalStrategy} instances to reason |
| * about the traversal. This strategy is not activated by default. However, graph system providers may choose to make |
| * this a default strategy in order to ensure their respective strategies are better able to operate. |
| * <p/> |
| * |
| * @author Marko A. Rodriguez (http://markorodriguez.com) |
| * @example <pre> |
| * __.out().map(v -> v.get().value("name")) // throws an IllegalStateException |
| * __.out().filter(v -> v.bulk() > 2) // throws an IllegalStateException |
| * __.choose(v -> v.sack() == 1,out(),in()) // throws an IllegalStateException |
| * __.select().by(v -> v.get().id()) // throws an IllegalStateException |
| * __.order().by(a,b -> a > b) // throws an IllegalStateException |
| * </pre> |
| */ |
| public final class LambdaRestrictionStrategy extends AbstractTraversalStrategy<TraversalStrategy.VerificationStrategy> implements TraversalStrategy.VerificationStrategy { |
| |
| private static final LambdaRestrictionStrategy INSTANCE = new LambdaRestrictionStrategy(); |
| |
| private LambdaRestrictionStrategy() { |
| } |
| |
| @Override |
| public void apply(final Traversal.Admin<?, ?> traversal) { |
| if (traversal instanceof LambdaHolder) |
| throw new VerificationException("The provided traversal is a lambda traversal: ", traversal); |
| for (final Step<?, ?> step : traversal.getSteps()) { |
| if (step instanceof LambdaHolder) |
| throw new VerificationException("The provided traversal contains a lambda step: " + step, traversal); |
| if (step instanceof ComparatorHolder) { |
| for (final Comparator<?> comparator : ((ComparatorHolder<?>) step).getComparators()) { |
| if (comparator instanceof LambdaHolder || comparator.toString().contains("$$Lambda$")) |
| throw new VerificationException("The provided step contains a lambda comparator: " + step, traversal); |
| } |
| } |
| } |
| } |
| |
| public static LambdaRestrictionStrategy instance() { |
| return INSTANCE; |
| } |
| } |