Migrated source code from Simantics SVN

[simantics/platform.git] / bundles / org.simantics.db.layer0 / src / org / simantics / db / layer0 / genericrelation / combinators / SelectByRelation.java

diff --git a/bundles/org.simantics.db.layer0/src/org/simantics/db/layer0/genericrelation/combinators/SelectByRelation.java b/bundles/org.simantics.db.layer0/src/org/simantics/db/layer0/genericrelation/combinators/SelectByRelation.java
new file mode 100644 (file)
index 0000000..344b9c8
--- /dev/null
+++ b/bundles/org.simantics.db.layer0/src/org/simantics/db/layer0/genericrelation/combinators/SelectByRelation.java
@@ -0,0 +1,80 @@
+/*******************************************************************************\r
+ * Copyright (c) 2007, 2010 Association for Decentralized Information Management\r
+ * in Industry THTH ry.\r
+ * All rights reserved. This program and the accompanying materials\r
+ * are made available under the terms of the Eclipse Public License v1.0\r
+ * which accompanies this distribution, and is available at\r
+ * http://www.eclipse.org/legal/epl-v10.html\r
+ *\r
+ * Contributors:\r
+ *     VTT Technical Research Centre of Finland - initial API and implementation\r
+ *******************************************************************************/\r
+package org.simantics.db.layer0.genericrelation.combinators;\r
+\r
+import gnu.trove.list.array.TIntArrayList;\r
+\r
+import java.util.ArrayList;\r
+import java.util.List;\r
+\r
+import org.simantics.db.ReadGraph;\r
+import org.simantics.db.exception.DatabaseException;\r
+import org.simantics.db.layer0.adapter.GenericRelation;\r
+import org.simantics.db.layer0.genericrelation.AbstractRelation;\r
+import org.simantics.utils.datastructures.Pair;\r
+\r
+\r
+public class SelectByRelation extends AbstractRelation {\r
+       \r
+       GenericRelation base;\r
+       int baseLength;\r
+       String bindingPattern;\r
+       int[] boundPositions;\r
+       GenericRelation constraint;\r
+       \r
+       public SelectByRelation(GenericRelation base, String bindingPattern, GenericRelation constraint) {\r
+               super();\r
+               this.base = base;\r
+               this.bindingPattern = bindingPattern;\r
+               TIntArrayList boundPositionArray = new TIntArrayList();\r
+               baseLength = bindingPattern.length();\r
+               for(int i=0;i<baseLength;++i)\r
+                       if(bindingPattern.charAt(i) == 'b') \r
+                               boundPositionArray.add(i);\r
+               boundPositions = boundPositionArray.toArray();\r
+               this.constraint = constraint;\r
+       }\r
+       \r
+       private Object[] map(Object[] tuple) {\r
+               Object[] result = new Object[boundPositions.length];\r
+               for(int i=0;i<result.length;++i)\r
+                       result[i] = tuple[boundPositions[i]];\r
+               return result;\r
+       }\r
+       \r
+       @Override\r
+       public boolean contains(ReadGraph g, Object[] tuple) throws DatabaseException {\r
+               assert tuple.length == baseLength;\r
+               return base.contains(g, tuple) && constraint.contains(g, map(tuple));\r
+       }\r
+       @Override\r
+       public Pair<String, String>[] getFields() {\r
+               return base.getFields();\r
+       }\r
+       @Override\r
+       public boolean isRealizable() {\r
+               return base.isRealizable();\r
+       }\r
+       @Override\r
+       public GenericRelation select(String bindingPattern, Object[] constants) {\r
+               return new SelectByRelation(base.select(bindingPattern, constants), bindingPattern, constraint);\r
+       }\r
+       @Override\r
+       public List<Object[]> realize(ReadGraph g) throws DatabaseException {\r
+               ArrayList<Object[]> result = new ArrayList<Object[]>();\r
+               for(Object[] tuple : base.realize(g))\r
+                       if(constraint.contains(g, map(tuple)))\r
+                               result.add(tuple);\r
+               return result;\r
+       }\r
+\r
+}\r