Migrated source code from Simantics SVN

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

diff --git a/bundles/org.simantics.db.layer0/src/org/simantics/db/layer0/genericrelation/combinators/Selection.java b/bundles/org.simantics.db.layer0/src/org/simantics/db/layer0/genericrelation/combinators/Selection.java
new file mode 100644 (file)
index 0000000..af9ad3a
--- /dev/null
+++ b/bundles/org.simantics.db.layer0/src/org/simantics/db/layer0/genericrelation/combinators/Selection.java
@@ -0,0 +1,117 @@
+/*******************************************************************************\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
+ * Selects tuples from the relation by fixing certain fields.\r
+ * Also projects the relation to unfixed fields. \r
+ * \r
+ * Do not use this class directly, because relations have often\r
+ * optimized selection methods, but use IRelation.select method.\r
+ */\r
+public class Selection extends AbstractRelation {\r
+       \r
+       AbstractRelation base;\r
+       int baseLength;\r
+       int[] constantPositions;\r
+       int[] variablePositions;\r
+       Object[] constants;\r
+       \r
+       public Selection(AbstractRelation base, String bindingPattern,\r
+                       Object[] constants) {\r
+               this.base = base;\r
+               TIntArrayList constantPositionArray = new TIntArrayList();\r
+               TIntArrayList variablePositionsArray = new TIntArrayList();\r
+               baseLength = bindingPattern.length();\r
+               for(int i=0;i<baseLength;++i)\r
+                       switch(bindingPattern.charAt(i)) {\r
+                       case 'b': constantPositionArray.add(i); break;\r
+                       case 'v': variablePositionsArray.add(i); break;\r
+                       }\r
+               constantPositions = constantPositionArray.toArray();\r
+               variablePositions = variablePositionsArray.toArray();\r
+               this.constants = constants;\r
+       }\r
+\r
+       @Override\r
+       public boolean contains(ReadGraph g, Object[] tuple) throws DatabaseException {\r
+               assert(tuple.length == variablePositions.length);\r
+               Object[] temp = new Object[baseLength];\r
+               for(int i=0;i<constantPositions.length;++i)\r
+                       temp[constantPositions[i]] = constants[i];\r
+               for(int i=0;i<variablePositions.length;++i)\r
+                       temp[variablePositions[i]] = tuple[i];\r
+               return base.contains(g, temp);\r
+       }\r
+\r
+       @Override\r
+       public boolean isRealizable() {\r
+               return base.isRealizable();\r
+       }\r
+\r
+       @Override\r
+       public List<Object[]> realize(ReadGraph g) throws DatabaseException {\r
+               ArrayList<Object[]> result = new ArrayList<Object[]>(); \r
+               loop:\r
+               for(Object[] tuple : base.realize(g)) {\r
+                       for(int i=0;i<constantPositions.length;++i)\r
+                               if(!constants[i].equals(tuple[constantPositions[i]]))\r
+                                       continue loop;\r
+                       Object[] temp = new Object[variablePositions.length];\r
+                       for(int i=0;i<variablePositions.length;++i)\r
+                               temp[i] = tuple[variablePositions[i]];\r
+                       result.add(temp);\r
+               }\r
+               return result;\r
+       }\r
+\r
+       @Override\r
+       public GenericRelation select(String bindingPattern, Object[] givenConstants) {\r
+               assert(bindingPattern.length() == variablePositions.length);\r
+               char[] baseBindingPattern = new char[baseLength];\r
+               Object[] baseConstants = new Object[baseLength];\r
+               for(int i=0;i<constantPositions.length;++i) {\r
+                       baseBindingPattern[constantPositions[i]] = 'b';\r
+                       baseConstants[constantPositions[i]] = constants[i];\r
+               }\r
+               int j = 0;\r
+               for(int i=0;i<variablePositions.length;++i) {\r
+                       char c = baseBindingPattern[variablePositions[i]] = bindingPattern.charAt(i);\r
+                       if(c == 'b')\r
+                               baseConstants[constantPositions[i]] = givenConstants[j++];\r
+               }\r
+               assert(j == givenConstants.length);\r
+               return base.select(new String(baseBindingPattern), constants);\r
+       }\r
+\r
+       @SuppressWarnings("unchecked")\r
+    @Override\r
+       public Pair<String, String>[] getFields() {\r
+               Pair<String, String>[] baseFields = base.getFields();\r
+               Pair<String, String>[] result = new Pair[variablePositions.length];\r
+               for(int i=0;i<variablePositions.length;++i)\r
+                       result[i] = baseFields[variablePositions[i]];\r
+               return result;\r
+       }       \r
+       \r
+}\r