1 /*******************************************************************************
\r
2 * Copyright (c) 2007, 2010 Association for Decentralized Information Management
\r
3 * in Industry THTH ry.
\r
4 * All rights reserved. This program and the accompanying materials
\r
5 * are made available under the terms of the Eclipse Public License v1.0
\r
6 * which accompanies this distribution, and is available at
\r
7 * http://www.eclipse.org/legal/epl-v10.html
\r
10 * VTT Technical Research Centre of Finland - initial API and implementation
\r
11 *******************************************************************************/
\r
12 package org.simantics.db.layer0.genericrelation.combinators;
\r
14 import java.util.ArrayList;
\r
15 import java.util.Collection;
\r
16 import java.util.List;
\r
18 import org.simantics.db.ReadGraph;
\r
19 import org.simantics.db.exception.DatabaseException;
\r
20 import org.simantics.db.layer0.adapter.GenericRelation;
\r
21 import org.simantics.db.layer0.genericrelation.AbstractRelation;
\r
22 import org.simantics.utils.datastructures.Pair;
\r
25 * Takes the intersection of multiple relations.
\r
27 public class Intersection extends AbstractRelation {
\r
29 GenericRelation realizable = null;
\r
30 Collection<GenericRelation> constraints;
\r
32 public Intersection(Collection<GenericRelation> relations) {
\r
33 for(GenericRelation relation : relations)
\r
34 if(realizable == null && relation.isRealizable()) {
\r
35 realizable = relation;
\r
38 constraints.add(relation);
\r
41 public Intersection(GenericRelation realizable, Collection<GenericRelation> constraints) {
\r
42 assert(realizable.isRealizable());
\r
43 this.realizable = realizable;
\r
44 this.constraints = constraints;
\r
48 public boolean contains(ReadGraph g, Object[] tuple) throws DatabaseException {
\r
49 if(!realizable.contains(g, tuple))
\r
51 for(GenericRelation relation : constraints)
\r
52 if(!relation.contains(g, tuple))
\r
58 public boolean isRealizable() {
\r
59 return realizable != null;
\r
63 public List<Object[]> realize(ReadGraph g) throws DatabaseException {
\r
64 ArrayList<Object[]> result = new ArrayList<Object[]>();
\r
66 for(Object[] tuple : realizable.realize(g)) {
\r
67 for(GenericRelation constraint : constraints)
\r
68 if(!constraint.contains(g, tuple))
\r
75 // TODO optimize select
\r
78 public GenericRelation selectByRelation(String bindingPattern,
\r
79 GenericRelation constraint) {
\r
80 if(realizable != null)
\r
81 return new Intersection(realizable.selectByRelation(bindingPattern, constraint),
\r
84 return super.selectByRelation(bindingPattern, constraint);
\r
88 public Pair<String, String>[] getFields() {
\r
89 if(realizable != null)
\r
90 return realizable.getFields();
\r
91 for(GenericRelation relation : constraints)
\r
92 return relation.getFields();
\r