| /* |
| * 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.indexing.external.matching; |
| |
| import java.util.ArrayList; |
| import java.util.HashMap; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.Set; |
| |
| import org.apache.rya.rdftriplestore.inference.DoNotExpandSP; |
| import org.apache.rya.rdftriplestore.utils.FixedStatementPattern; |
| import org.eclipse.rdf4j.query.algebra.Filter; |
| import org.eclipse.rdf4j.query.algebra.Join; |
| import org.eclipse.rdf4j.query.algebra.QueryModelNode; |
| import org.eclipse.rdf4j.query.algebra.TupleExpr; |
| import org.eclipse.rdf4j.query.algebra.ValueExpr; |
| import org.eclipse.rdf4j.query.algebra.evaluation.impl.ExternalSet; |
| |
| import com.google.common.base.Preconditions; |
| import com.google.common.collect.Sets; |
| |
| /** |
| * This class represents a portion of a {@link TupleExpr} query that PCJ queries |
| * are compared to. A JoinSegment is comprised of a collection of |
| * {@link QueryModelNode}s that are connected by {@link Join}s. In the case, the |
| * QueryModelNodes can commute within the JoinSegment, which makes JoinSegments |
| * a natural way to partition a query for PCJ matching. A query is decomposed |
| * into JoinSegments and PCJ queries can easily be compared to the |
| * {@link QueryModelNode}s contained in the segment using set operations. |
| * |
| */ |
| public class JoinSegment<T extends ExternalSet> extends AbstractQuerySegment<T> { |
| |
| public JoinSegment(Join join) { |
| Preconditions.checkNotNull(join); |
| Preconditions.checkArgument(!MatcherUtilities.segmentContainsLeftJoins(join)); |
| createJoinSegment(join); |
| } |
| |
| public JoinSegment(Filter filter) { |
| Preconditions.checkNotNull(filter); |
| Preconditions.checkArgument(!MatcherUtilities.segmentContainsLeftJoins(filter)); |
| createJoinSegment(filter); |
| } |
| |
| public JoinSegment(Set<QueryModelNode> unorderedNodes, List<QueryModelNode> orderedNodes, Map<ValueExpr, Filter> filterMap) { |
| this.unorderedNodes = unorderedNodes; |
| this.orderedNodes = orderedNodes; |
| this.conditionMap = filterMap; |
| } |
| |
| private void createJoinSegment(TupleExpr te) { |
| orderedNodes = getJoinArgs(te, orderedNodes); |
| unorderedNodes = Sets.newHashSet(orderedNodes); |
| } |
| |
| /** |
| * This method matches the ordered nodes returned by |
| * {@link JoinSegment#getOrderedNodes()} for nodeToReplace with a subset of |
| * the ordered nodes for this JoinSegment. The order of the nodes for |
| * nodeToReplace must match the order of the nodes as a subset of |
| * orderedNodes |
| * |
| * @param nodeToReplace |
| * - nodes to be replaced by pcj |
| * @param pcj |
| * - pcj node that will replace specified query nodes |
| */ |
| @Override |
| public boolean replaceWithExternalSet(QuerySegment<T> nodeToReplace, T set) { |
| Preconditions.checkNotNull(nodeToReplace); |
| Preconditions.checkNotNull(set); |
| if (!containsQuerySegment(nodeToReplace)) { |
| return false; |
| } |
| Set<QueryModelNode> nodeSet = nodeToReplace.getUnOrderedNodes(); |
| orderedNodes.removeAll(nodeSet); |
| orderedNodes.add(set); |
| unorderedNodes.removeAll(nodeSet); |
| unorderedNodes.add(set); |
| for (QueryModelNode q : nodeSet) { |
| if (q instanceof ValueExpr) { |
| conditionMap.remove(q); |
| } |
| } |
| return true; |
| } |
| |
| /** |
| * |
| * @param tupleExpr |
| * - the query object that will be traversed by this method |
| * @param joinArgs |
| * - all nodes connected by Joins and Filters |
| * @return - List containing all nodes connected by Joins, LeftJoins, and |
| * Filters. This List contains the |
| * @param ValueExpr |
| * in place of the Filter |
| */ |
| private List<QueryModelNode> getJoinArgs(TupleExpr tupleExpr, List<QueryModelNode> joinArgs) { |
| |
| if (tupleExpr instanceof Join) { |
| if (!(((Join) tupleExpr).getLeftArg() instanceof FixedStatementPattern) |
| && !(((Join) tupleExpr).getRightArg() instanceof DoNotExpandSP)) { |
| Join join = (Join) tupleExpr; |
| getJoinArgs(join.getRightArg(), joinArgs); |
| getJoinArgs(join.getLeftArg(), joinArgs); |
| } |
| } else if (tupleExpr instanceof Filter) { |
| Filter filter = (Filter) tupleExpr; |
| joinArgs.add(filter.getCondition()); |
| conditionMap.put(filter.getCondition(), filter); |
| getJoinArgs(filter.getArg(), joinArgs); |
| } else { |
| joinArgs.add(tupleExpr); |
| } |
| return joinArgs; |
| } |
| |
| |
| @Override |
| public JoinSegment<T> clone() { |
| List<QueryModelNode> order = new ArrayList<>(); |
| for(QueryModelNode node: orderedNodes) { |
| order.add(node.clone()); |
| } |
| |
| Set<QueryModelNode> unorder = Sets.newHashSet(order); |
| |
| Map<ValueExpr, Filter> map = new HashMap<>(); |
| for(ValueExpr expr: conditionMap.keySet()) { |
| map.put(expr.clone(), conditionMap.get(expr).clone()); |
| } |
| return new JoinSegment<T>(unorder, order, map); |
| } |
| |
| |
| } |