Adding JMCR-Stable version

[Benchmarks_CSolver.git] / JMCR-Stable / real-world application / derby-10.3.2.1 / java / engine / org / apache / derby / iapi / store / access / KeyHasher.java

diff --git a/JMCR-Stable/real-world application/derby-10.3.2.1/java/engine/org/apache/derby/iapi/store/access/KeyHasher.java b/JMCR-Stable/real-world application/derby-10.3.2.1/java/engine/org/apache/derby/iapi/store/access/KeyHasher.java
new file mode 100644 (file)
index 0000000..f98df0b
--- /dev/null
+++ b/JMCR-Stable/real-world application/derby-10.3.2.1/java/engine/org/apache/derby/iapi/store/access/KeyHasher.java
@@ -0,0 +1,128 @@
+/*\r
+\r
+   Derby - Class org.apache.derby.iapi.store.access.KeyHasher\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.iapi.store.access;\r
+\r
+import org.apache.derby.iapi.services.sanity.SanityManager;\r
+\r
+/**\r
+       Provides the ability to hash on multiple objects.\r
+*/\r
+public class KeyHasher \r
+{\r
+       \r
+       private final Object[] objects;\r
+\r
+       public KeyHasher(int size)\r
+       {\r
+               objects = new Object[size];\r
+       }\r
+\r
+       /**\r
+        * Set array element at the specified index to the specified object.\r
+        *\r
+        * @param index         The specified index\r
+        * @param object        The specified object.\r
+        */\r
+       public void setObject(int index, Object object)\r
+       {\r
+               objects[index] = object;\r
+       }\r
+\r
+       /**\r
+        * Get the object stored at the specified index.\r
+        *\r
+        * @param index The specified index.\r
+        *\r
+        * @return The object stored in the array element.\r
+        */\r
+       public Object getObject(int index)\r
+       {\r
+               return objects[index];\r
+       }\r
+\r
+       /**\r
+        * Static method to return the object to hash on.\r
+        * (Object stored in specifed array, if only a single\r
+        * object, otherwise a KeyHasher wrapping the\r
+        * objects to hash on.\r
+        * (NOTE: We optimize for in-memory hash tables, hence\r
+        * we only create a wrapper when needed.)\r
+        *\r
+        * @param objects       The array of objects to consider\r
+        * @param indexes       The indexes of the objects in the hash key.\r
+        *\r
+        * @return      The object to hash on.\r
+        */\r
+       public static Object buildHashKey(Object[] objects,\r
+                                                                         int[] indexes)\r
+       {\r
+               // Hash on single object\r
+               if (indexes.length == 1)\r
+               {\r
+                       return objects[indexes[0]];\r
+               }\r
+\r
+               // Hash on multiple objects\r
+               KeyHasher mh = new KeyHasher(indexes.length);\r
+               for (int index = 0; index < indexes.length; index++)\r
+               {\r
+                       mh.setObject(index, objects[indexes[index]]);\r
+               }\r
+               return mh;\r
+       }\r
+\r
+       /*\r
+       ** Methods from java.lang.Object\r
+       */\r
+\r
+       public int hashCode()\r
+       {\r
+               int retval = 0;\r
+               for (int index = 0; index < objects.length; index++)\r
+               {\r
+                       retval += objects[index].hashCode();\r
+               }\r
+\r
+               return retval;\r
+       }\r
+\r
+       public boolean equals(Object obj)\r
+       {\r
+               if (!(obj instanceof KeyHasher))\r
+                       return false;\r
+\r
+               KeyHasher mh = (KeyHasher) obj;\r
+\r
+               if (mh.objects.length != objects.length)\r
+                       return false;\r
+\r
+               for (int index = 0; index < objects.length; index++)\r
+               {\r
+                       if (! (mh.objects[index].equals(objects[index])))\r
+                       {\r
+                               return false;\r
+                       }\r
+               }\r
+\r
+               return true;\r
+       }\r
+}\r