ChangeLogTag:Sun May 11 10:44:56 2003 Balachandran Natarajan <bala@dre.vanderbilt.edu>

1 files changed, 125 insertions, 0 deletions

diff --git a/TAO/tao/ObjectKey_Table.h b/TAO/tao/ObjectKey_Table.h
new file mode 100644
index 00000000000..52ded9b5294
--- /dev/null
+++ b/TAO/tao/ObjectKey_Table.h
@@ -0,0 +1,125 @@
+// -*- C++ -*-
+
+//=============================================================================
+/**
+ *  @file ObjectKey_Table.h
+ *
+ *  $Id$
+ *
+ *  @author Balachandran Natarajan <bala@dre.vanderbilt.edu>
+ */
+//=============================================================================
+#ifndef TAO_OBJECTKEY_TABLE_H
+#define TAO_OBJECTKEY_TABLE_H
+#include "ace/pre.h"
+#include "ace/RB_Tree.h"
+
+#if !defined (ACE_LACKS_PRAGMA_ONCE)
+# pragma once
+#endif /* ACE_LACKS_PRAGMA_ONCE */
+
+#include "tao/TAO_Export.h"
+
+
+// Forward declarations
+class TAO_ORB_Core;
+
+
+namespace TAO
+{
+
+  // Forward declarations within the namespace..
+
+  class ObjectKey;
+  class Refcounted_ObjectKey;
+
+  /**
+   * @class ObjectKey_Table
+   *
+   * @brief Table that maintains the set of ObjectKey's seen by the
+   * ORB.
+   *
+   * The ORB maintains one table for the whole ORB. ObjectKeys
+   * generated by the ORB or the ones seen by the ORB from remote
+   * ORB's are stored here. The ObjectKeys are stored through a
+   * wrapper which encapsulates the refcount on them. This class
+   * actually provides the synchronization mechanism for manipulating
+   * the reference counts on the object keys provided by the wrapper
+   * class.
+   *
+   * This class does not offer a find () call with a reason. The call
+   * to bind () will return a pointer which is expected to be cached
+   * by the client/caller and use the pointer in every invocation.
+   *
+   * @NOTE: This class uses the ACE_RB_Tree to maintain the table of
+   * ObjectKeys. The RB_Tree has good insertion and lookup
+   * properties. Its Iteration properties are not that good, but we
+   * dont need to do much iteration unless we are closing down the
+   * table.
+   *
+   * @NOTE: The reasons to use RB_Tree are its good dynamic
+   * properties. We should try to strategize the class to use either a
+   * Hash_Map or a RB_Tree based on some runtime option. For that we
+   * need an adapter class in ACE, like an ACE_Lock_Adapter class. We
+   * will do that if our instrumentation shows the need for it.
+   *
+   */
+  class TAO_Export ObjectKey_Table
+  {
+  public:
+    /// Default Constructor and destructor..
+    ObjectKey_Table (void);
+
+    ~ObjectKey_Table (void);
+
+    /// Initialize method that sets up the underlying lock and other
+    /// related stuff.
+    int init (TAO_ORB_Core *orb);
+
+    /// Iterates and unbinds the contents of the table.
+    int destroy (void);
+
+    /// Bind the ObjectKey in the table.
+    /**
+     * Bind an ObjectKey in the table and return a pointer to the
+     * Refcounted_ObjectKey which the client can use. If the ObjectKey
+     * is already available in the table, this operation just
+     * increments the refcount on the ObjectKey. If the ObjectKey is
+     * new it is bounded to the table. Returns a 0 on success and a -1
+     * on failure.
+     */
+    int bind (const ObjectKey &key,
+              Refcounted_ObjectKey *&key_new);
+
+    /// Unbind an ObjectKey from the table.
+    int unbind (TAO::Refcounted_ObjectKey *&key);
+
+  protected:
+    /// Implementation for bind ().
+    int bind_i (u_long hash_val,
+                const ObjectKey &key,
+                Refcounted_ObjectKey *&key_new);
+
+    /// Implementation for unbind ().
+    int unbind_i (Refcounted_ObjectKey *&key);
+
+  private:
+
+    // Some useful typedefs.
+    typedef unsigned long ExtId;
+
+    typedef ACE_RB_Tree<ExtId,
+                        TAO::Refcounted_ObjectKey *,
+                        ACE_Less_Than <ExtId>,
+                        ACE_Null_Mutex> TABLE;
+
+    /// Lock for the table.
+    ACE_Lock *lock_;
+
+    /// Table that contains the data
+    TABLE table_;
+  };
+}
+
+#include "ace/post.h"
+#endif /*TAO_OBJECT_KEY_TABLE_H*/