bundles/org.simantics.layer0.utils/src/org/simantics/layer0/utils/binaryPredicates/TransitiveClosure.java

   1 /*******************************************************************************
   2  * Copyright (c) 2007, 2010 Association for Decentralized Information Management
   3  * in Industry THTH ry.
   4  * All rights reserved. This program and the accompanying materials
   5  * are made available under the terms of the Eclipse Public License v1.0
   6  * which accompanies this distribution, and is available at
   7  * http://www.eclipse.org/legal/epl-v10.html
   8  *
   9  * Contributors:
  10  *     VTT Technical Research Centre of Finland - initial API and implementation
  11  *******************************************************************************/
  12 package org.simantics.layer0.utils.binaryPredicates;
  13
  14 import java.util.ArrayDeque;
  15 import java.util.Collection;
  16 import java.util.Deque;
  17 import java.util.HashSet;
  18 import java.util.Set;
  19
  20 import org.simantics.db.Resource;
  21 import org.simantics.db.ReadGraph;
  22 import org.simantics.db.WriteGraph;
  23 import org.simantics.db.exception.DatabaseException;
  24 import org.simantics.utils.datastructures.Pair;
  25
  26 public class TransitiveClosure extends BinaryPredicate {
  27         IBinaryPredicate predicate;
  28
  29
  30         public TransitiveClosure(IBinaryPredicate predicate) {
  31                 this.predicate = predicate;
  32         }
  33
  34         @Override
  35         public void add(WriteGraph g, Resource subject, Resource object) throws DatabaseException {
  36                 if(!has(g, subject, object))
  37                         predicate.add(g, subject, object);
  38         }
  39
  40         @Override
  41         public Collection<Resource> getObjects(ReadGraph g, Resource subject) throws DatabaseException {
  42                 Deque<Resource> unprocessed = new ArrayDeque<Resource>();
  43                 unprocessed.add(subject);
  44                 Set<Resource> result = new HashSet<Resource>();
  45                 while(!unprocessed.isEmpty())
  46                         for(Resource r : predicate.getObjects(g, unprocessed.pop()))
  47                                 if(result.add(r))
  48                                         unprocessed.push(r);
  49                 return result;
  50         }
  51
  52         @Override
  53         public Collection<Pair<Resource, Resource>> getStatements(ReadGraph g) {
  54                 // TODO Auto-generated method stub
  55                 return null;
  56         }
  57
  58         @Override
  59         public Collection<Resource> getSubjects(ReadGraph g, Resource object) throws DatabaseException {
  60                 Deque<Resource> unprocessed = new ArrayDeque<Resource>();
  61                 unprocessed.add(object);
  62                 Set<Resource> result = new HashSet<Resource>();
  63                 while(!unprocessed.isEmpty())
  64                         for(Resource r : predicate.getSubjects(g, unprocessed.pop()))
  65                                 if(result.add(r))
  66                                         unprocessed.push(r);
  67                 return result;
  68         }
  69
  70         @Override
  71         public boolean has(ReadGraph g, Resource subject, Resource object) throws DatabaseException {
  72                 Deque<Resource> unprocessed = new ArrayDeque<Resource>();
  73                 unprocessed.add(subject);
  74                 Set<Resource> objects = new HashSet<Resource>();
  75                 while(!unprocessed.isEmpty())
  76                         for(Resource r : predicate.getObjects(g, unprocessed.pop()))
  77                                 if(r.equals(object))
  78                                         return true;
  79                                 else if(objects.add(r))
  80                                         unprocessed.push(r);
  81                 return false;
  82         }
  83
  84         @Override
  85         public void remove(WriteGraph g, Resource subject, Resource object) {
  86                 throw new UnsupportedOperationException();
  87         }
  88
  89         @Override
  90         public boolean supportsAdditions() {
  91                 return predicate.supportsAdditions();
  92         }
  93
  94         @Override
  95         public boolean supportsGetObjects() {
  96                 return predicate.supportsGetObjects();
  97         }
  98
  99         @Override
 100         public boolean supportsGetStatements() {
 101                 return false; // FIXME: just unimplemented
 102         }
 103
 104         @Override
 105         public boolean supportsGetSubjects() {
 106                 return predicate.supportsGetSubjects();
 107         }
 108
 109         @Override
 110         public boolean supportsRemovals() {
 111                 return false;
 112         }
 113
 114         @Override
 115         public int hashCode() {
 116                 final int prime = 31;
 117                 int result = 1;
 118                 result = prime * result
 119                                 + ((predicate == null) ? 0 : predicate.hashCode());
 120                 return result;
 121         }
 122
 123         @Override
 124         public boolean equals(Object obj) {
 125                 if (this == obj)
 126                         return true;
 127                 if (obj == null)
 128                         return false;
 129                 if (getClass() != obj.getClass())
 130                         return false;
 131                 TransitiveClosure other = (TransitiveClosure) obj;
 132                 if (predicate == null) {
 133                         if (other.predicate != null)
 134                                 return false;
 135                 } else if (!predicate.equals(other.predicate))
 136                         return false;
 137                 return true;
 138         }
 139
 140 }