Adding JMCR-Stable version

[Benchmarks_CSolver.git] / JMCR-Stable / real-world application / MyDerby-10.3 / java / engine / org / apache / derby / vti / VTICosting.java

diff --git a/JMCR-Stable/real-world application/MyDerby-10.3/java/engine/org/apache/derby/vti/VTICosting.java b/JMCR-Stable/real-world application/MyDerby-10.3/java/engine/org/apache/derby/vti/VTICosting.java
new file mode 100644 (file)
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--- /dev/null
+++ b/JMCR-Stable/real-world application/MyDerby-10.3/java/engine/org/apache/derby/vti/VTICosting.java
@@ -0,0 +1,90 @@
+/*\r
+\r
+   Derby - Class org.apache.derby.vti.VTICosting\r
+\r
+   Licensed to the Apache Software Foundation (ASF) under one or more\r
+   contributor license agreements.  See the NOTICE file distributed with\r
+   this work for additional information regarding copyright ownership.\r
+   The ASF licenses this file to You under the Apache License, Version 2.0\r
+   (the "License"); you may not use this file except in compliance with\r
+   the License.  You may obtain a copy of the License at\r
+\r
+      http://www.apache.org/licenses/LICENSE-2.0\r
+\r
+   Unless required by applicable law or agreed to in writing, software\r
+   distributed under the License is distributed on an "AS IS" BASIS,\r
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\r
+   See the License for the specific language governing permissions and\r
+   limitations under the License.\r
+\r
+ */\r
+\r
+package org.apache.derby.vti;\r
+\r
+import java.sql.SQLException;\r
+\r
+/**\r
+  *    VTICosting is the interface that the query optimizer uses\r
+  * to cost VTIs.\r
+  * \r
+  The methods on the interface provide the optimizer\r
+  * with the following information:\r
+  <UL> \r
+  <LI> the estimated number of rows returned by the VTI in a single instantiation.\r
+  <LI> the estimated cost to instantiate and iterate through the VTI.\r
+  <LI> whether or not the VTI can be instantiated multiple times within a single query execution\r
+  </UL>\r
+  * <P>\r
+  * This class can only be used within an SQL-J statement.  Using the methods\r
+  * in application-side Java code results in Exceptions being thrown.\r
+  *\r
+  * @see org.apache.derby.vti.VTIEnvironment\r
+ */\r
+public interface VTICosting\r
+{\r
+       /**\r
+        * A useful constant: the default estimated number of rows returned by a VTI.\r
+        */\r
+       public static final double defaultEstimatedRowCount             = 10000d;\r
+       /**\r
+          A useful constant: The default estimated cost of instantiating and iterating throught a VTI.\r
+        */\r
+       public static final double defaultEstimatedCost                 = 100000d;\r
+\r
+       /**\r
+        *  Get the estimated row count for a single scan of a VTI.\r
+        *\r
+        *  @param vtiEnvironment The VTIEnvironment.\r
+        *\r
+        *  @return     The estimated row count for a single scan of a VTI.\r
+        *\r
+        *  @exception SQLException thrown if the costing fails.\r
+        */\r
+       public double getEstimatedRowCount(VTIEnvironment vtiEnvironment)\r
+               throws SQLException;\r
+\r
+       /**\r
+        *  Get the estimated cost for a single instantiation of a VTI.\r
+        *\r
+        *  @param vtiEnvironment The VTIEnvironment.\r
+        *\r
+        *  @return     The estimated cost for a single instantiation of a VTI.\r
+        *\r
+        *  @exception SQLException thrown if the costing fails.\r
+        */\r
+       public double getEstimatedCostPerInstantiation(VTIEnvironment vtiEnvironment)\r
+               throws SQLException;\r
+\r
+       /**\r
+                Find out if the ResultSet of the VTI can be instantiated multiple times.\r
+\r
+                @param vtiEnvironment The VTIEnvironment.\r
+\r
+                @return        True if the ResultSet can be instantiated multiple times, false if\r
+                can only be instantiated once.\r
+\r
+                @exception SQLException thrown if the costing fails.\r
+        */\r
+       public boolean supportsMultipleInstantiations(VTIEnvironment vtiEnvironment)\r
+               throws SQLException;\r
+}\r