1 /*******************************************************************************
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2 * Copyright (c) 2007, 2010 Association for Decentralized Information Management
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3 * in Industry THTH ry.
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4 * All rights reserved. This program and the accompanying materials
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5 * are made available under the terms of the Eclipse Public License v1.0
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6 * which accompanies this distribution, and is available at
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7 * http://www.eclipse.org/legal/epl-v10.html
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10 * VTT Technical Research Centre of Finland - initial API and implementation
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11 *******************************************************************************/
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12 package org.simantics.db.layer0.genericrelation.combinators;
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14 import java.util.ArrayList;
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15 import java.util.Collection;
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16 import java.util.List;
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18 import org.simantics.db.ReadGraph;
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19 import org.simantics.db.exception.DatabaseException;
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20 import org.simantics.db.layer0.adapter.GenericRelation;
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21 import org.simantics.db.layer0.genericrelation.AbstractRelation;
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22 import org.simantics.utils.datastructures.Pair;
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25 * Takes the union of multiple relations. Does not remove duplicates.
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27 public class Union extends AbstractRelation {
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29 Collection<GenericRelation> relations;
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31 public Union(Collection<GenericRelation> relations) {
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32 this.relations = relations;
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36 public boolean contains(ReadGraph g, Object[] tuple) throws DatabaseException {
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37 for(GenericRelation relation : relations)
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38 if(relation.contains(g, tuple))
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44 public boolean isRealizable() {
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45 for(GenericRelation relation : relations)
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46 if(!relation.isRealizable())
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52 public List<Object[]> realize(ReadGraph g) throws DatabaseException {
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53 ArrayList<List<Object[]>> results = new ArrayList<List<Object[]>>(relations.size());
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54 for(GenericRelation relation : relations)
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55 results.add(relation.realize(g));
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57 for(List<Object[]> part : results)
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58 size += part.size();
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59 ArrayList<Object[]> result = new ArrayList<Object[]>(size);
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60 for(List<Object[]> part : results)
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61 result.addAll(part);
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66 public GenericRelation selectByRelation(String bindingPattern, GenericRelation constraint) {
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67 ArrayList<GenericRelation> semijoinRelations = new ArrayList<GenericRelation>(relations.size());
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68 for(GenericRelation relation : relations)
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69 semijoinRelations.add(relation.selectByRelation(bindingPattern, constraint));
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70 return new Union(semijoinRelations);
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74 public GenericRelation select(String bindingPattern, Object[] constants) {
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75 ArrayList<GenericRelation> selectedRelations = new ArrayList<GenericRelation>(relations.size());
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76 for(GenericRelation relation : relations)
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77 selectedRelations.add(relation.select(bindingPattern, constants));
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78 return new Union(selectedRelations);
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82 public Pair<String, String>[] getFields() {
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83 for(GenericRelation relation : relations)
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84 return relation.getFields();
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