| /* |
| * 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.rya.mongodb.aggregation; |
| |
| import org.apache.hadoop.conf.Configurable; |
| import org.apache.hadoop.conf.Configuration; |
| import org.apache.rya.mongodb.StatefulMongoDBRdfConfiguration; |
| import org.eclipse.rdf4j.query.BindingSet; |
| import org.eclipse.rdf4j.query.Dataset; |
| import org.eclipse.rdf4j.query.algebra.TupleExpr; |
| import org.eclipse.rdf4j.query.algebra.evaluation.QueryOptimizer; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import com.google.common.base.Preconditions; |
| |
| /** |
| * MongoDB-specific query optimizer that replaces part or all of a SPARQL query |
| * tree with a MongoDB aggregation pipeline. |
| * <p> |
| * Transforms query trees using {@link SparqlToPipelineTransformVisitor}. If |
| * possible, this visitor will replace portions of the query tree, or the entire |
| * query, with an equivalent aggregation pipeline (contained in an |
| * {@link AggregationPipelineQueryNode}), thereby allowing query logic to be |
| * evaluated by the MongoDB server rather than by the client. |
| */ |
| public class AggregationPipelineQueryOptimizer implements QueryOptimizer, Configurable { |
| private StatefulMongoDBRdfConfiguration conf; |
| private Logger logger = LoggerFactory.getLogger(getClass()); |
| |
| @Override |
| public void optimize(TupleExpr tupleExpr, Dataset dataset, BindingSet bindings) { |
| SparqlToPipelineTransformVisitor pipelineVisitor = new SparqlToPipelineTransformVisitor(conf); |
| try { |
| tupleExpr.visit(pipelineVisitor); |
| } catch (Exception e) { |
| logger.error("Error attempting to transform query using the aggregation pipeline", e); |
| } |
| } |
| |
| /** |
| * @throws IllegalArgumentException if conf is not a {@link StatefulMongoDBRdfConfiguration}. |
| */ |
| @Override |
| public void setConf(Configuration conf) { |
| Preconditions.checkNotNull(conf); |
| Preconditions.checkArgument(conf instanceof StatefulMongoDBRdfConfiguration, |
| "Expected an instance of %s; received %s", |
| StatefulMongoDBRdfConfiguration.class.getName(), conf.getClass().getName()); |
| this.conf = (StatefulMongoDBRdfConfiguration) conf; |
| } |
| |
| @Override |
| public StatefulMongoDBRdfConfiguration getConf() { |
| return conf; |
| } |
| } |