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

   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
   8  *\r
   9  * Contributors:\r
  10  *     VTT Technical Research Centre of Finland - initial API and implementation\r
  11  *******************************************************************************/\r
  12 package org.simantics.layer0.utils.binaryPredicates;\r
  13 \r
  14 import java.util.Collection;\r
  15 import java.util.HashSet;\r
  16 import java.util.Set;\r
  17 \r
  18 import org.simantics.db.Resource;\r
  19 import org.simantics.db.ReadGraph;\r
  20 import org.simantics.db.WriteGraph;\r
  21 import org.simantics.db.exception.DatabaseException;\r
  22 import org.simantics.utils.datastructures.Pair;\r
  23 \r
  24 public class CompositePredicate extends BinaryPredicate {\r
  25         IBinaryPredicate first;\r
  26         IBinaryPredicate second;\r
  27         \r
  28         int hasStatementDirection;\r
  29         int getStatementsDirection;\r
  30         \r
  31         public CompositePredicate(IBinaryPredicate first, IBinaryPredicate second) {\r
  32                 this.first = first;\r
  33                 this.second = second;           \r
  34                 if(first.supportsGetStatements() && second.supportsGetObjects())\r
  35                         getStatementsDirection = 1;\r
  36                 else if(second.supportsGetStatements() && first.supportsGetSubjects())\r
  37                         getStatementsDirection = 2;\r
  38                 else\r
  39                         this.getStatementsDirection = 0;\r
  40                 if(first.supportsGetObjects())\r
  41                         hasStatementDirection = 1;\r
  42                 else if(second.supportsGetSubjects())\r
  43                         hasStatementDirection = 2;\r
  44                 else\r
  45                         throw new IllegalArgumentException("Cannot compose binary predicates such that the first one does not support getObjects and the second one does not support getSubjects.");\r
  46         }\r
  47 \r
  48         @Override\r
  49         public Collection<Resource> getObjects(ReadGraph g, Resource subject) throws DatabaseException {\r
  50                 Set<Resource> result = new HashSet<Resource>();\r
  51                 for(Resource r : first.getObjects(g, subject))\r
  52                         result.addAll(second.getObjects(g, r));\r
  53                 return result;\r
  54         }\r
  55 \r
  56         @Override\r
  57         public Collection<Pair<Resource, Resource>> getStatements(ReadGraph g) throws DatabaseException {\r
  58                 Set<Pair<Resource, Resource>> result = \r
  59                         new HashSet<Pair<Resource, Resource>>();\r
  60                 if(getStatementsDirection == 1)\r
  61                         for(Pair<Resource, Resource> p : first.getStatements(g))\r
  62                                 for(Resource r : second.getObjects(g, p.second))\r
  63                                         result.add(new Pair<Resource, Resource>(p.first, r));\r
  64                 else if(getStatementsDirection == 2)\r
  65                         for(Pair<Resource, Resource> p : second.getStatements(g))\r
  66                                 for(Resource r : second.getSubjects(g, p.first))\r
  67                                         result.add(new Pair<Resource, Resource>(r, p.second));\r
  68                 else\r
  69                         throw new UnsupportedOperationException();\r
  70                 return result;\r
  71         }\r
  72 \r
  73         @Override\r
  74         public Collection<Resource> getSubjects(ReadGraph g, Resource object) throws DatabaseException {\r
  75                 Set<Resource> result = new HashSet<Resource>();\r
  76                 for(Resource r : second.getSubjects(g, object))\r
  77                         result.addAll(first.getSubjects(g, r));\r
  78                 return result;\r
  79         }\r
  80 \r
  81         @Override\r
  82         public boolean has(ReadGraph g, Resource subject, Resource object) throws DatabaseException {\r
  83                 if(hasStatementDirection == 1) {\r
  84                         for(Resource r : first.getObjects(g, subject))\r
  85                                 if(second.has(g, r, object))\r
  86                                         return true;\r
  87                 }\r
  88                 else {\r
  89                         for(Resource r : second.getSubjects(g, object))\r
  90                                 if(second.has(g, subject, r))\r
  91                                         return true;\r
  92                 }\r
  93                 return false;\r
  94         }\r
  95 \r
  96         @Override\r
  97         public void add(WriteGraph g, Resource subject, Resource object) {\r
  98                 throw new UnsupportedOperationException();\r
  99         }\r
 100 \r
 101         @Override\r
 102         public void remove(WriteGraph g, Resource subject, Resource object) {\r
 103                 throw new UnsupportedOperationException();\r
 104         }\r
 105 \r
 106         @Override\r
 107         public boolean supportsAdditions() {\r
 108                 return false;\r
 109         }\r
 110 \r
 111         @Override\r
 112         public boolean supportsGetObjects() {\r
 113                 return first.supportsGetObjects() && second.supportsGetObjects();\r
 114         }\r
 115 \r
 116         @Override\r
 117         public boolean supportsGetStatements() {\r
 118                 return getStatementsDirection != 0;\r
 119         }\r
 120 \r
 121         @Override\r
 122         public boolean supportsGetSubjects() {\r
 123                 return first.supportsGetSubjects() && second.supportsGetSubjects();\r
 124         }\r
 125 \r
 126         @Override\r
 127         public boolean supportsRemovals() {             \r
 128                 return false;\r
 129         }\r
 130 \r
 131         @Override\r
 132         public int hashCode() {\r
 133                 final int prime = 31;\r
 134                 int result = 1;\r
 135                 result = prime * result + ((first == null) ? 0 : first.hashCode());\r
 136                 result = prime * result + ((second == null) ? 0 : second.hashCode());\r
 137                 return result;\r
 138         }\r
 139 \r
 140         @Override\r
 141         public boolean equals(Object obj) {\r
 142                 if (this == obj)\r
 143                         return true;\r
 144                 if (obj == null)\r
 145                         return false;\r
 146                 if (getClass() != obj.getClass())\r
 147                         return false;\r
 148                 CompositePredicate other = (CompositePredicate) obj;\r
 149                 if (first == null) {\r
 150                         if (other.first != null)\r
 151                                 return false;\r
 152                 } else if (!first.equals(other.first))\r
 153                         return false;\r
 154                 if (second == null) {\r
 155                         if (other.second != null)\r
 156                                 return false;\r
 157                 } else if (!second.equals(other.second))\r
 158                         return false;\r
 159                 return true;\r
 160         }       \r
 161         \r
 162 }\r