r6254 - /branches/singleton_fixing/data/__init__.py -- May 22, 2008 - 16:55

Author: bugman
Date: Thu May 22 16:55:25 2008
New Revision: 6254

URL: http://svn.gna.org/viewcvs/relax?rev=6254&view=rev
Log:
Changed the design of the relax data store singleton.

The singleton saving and loading problem is discussed in the thread starting 
at:
https://mail.gna.org/public/relax-devel/2007-11/msg00021.html (Message-id:
<7f080ed10711201001s59a00533pf3c0ee3f88a79edb@xxxxxxxxxxxxxx>).  For more 
history, see the thread
starting at https://mail.gna.org/public/relax-devel/2007-03/msg00046.html 
(Message-id:
<7f080ed10703140609p70d35295ye10ee5939da494a2@xxxxxxxxxxxxxx>) and the 
original singleton idea at
https://mail.gna.org/public/relax-devel/2007-03/msg00012.html (Message-id:
<7f080ed10703070006s309a1e1do38e621f48d8f6d9e@xxxxxxxxxxxxxx>).

This reverts to the original singleton behaviour in the last link.  Note that 
this will be reverted
to the current singleton design once a good solution to the pickling issues 
can be found.


Modified:
    branches/singleton_fixing/data/__init__.py

Modified: branches/singleton_fixing/data/__init__.py
URL: 
http://svn.gna.org/viewcvs/relax/branches/singleton_fixing/data/__init__.py?rev=6254&r1=6253&r2=6254&view=diff
==============================================================================
--- branches/singleton_fixing/data/__init__.py (original)
+++ branches/singleton_fixing/data/__init__.py Thu May 22 16:55:25 2008
@@ -38,12 +38,26 @@
             'main' ]
 
 
-class Data2(dict):
+class Relax_data_store(dict):
     """The relax data storage object."""
 
     # The current data pipe.
     current_pipe = None
 
+    # Class variable for storing the class instance.
+    instance = None
+
+    def __new__(self, *args, **kargs): 
+        """Replacement function for implementing the singleton design 
pattern."""
+
+        # First initialisation.
+        if self.instance is None:
+            self.instance = dict.__new__(self, *args, **kargs)
+
+        # Already initialised, so return the instance.
+        return self.instance
+
+    
     def __repr__(self):
         """The string representation of the object.
 
@@ -128,7 +142,3 @@
 
         # Change the current data pipe.
         self.current_pipe = pipe_name
-
-# Rebind the name Data with an instance to prevent accidental creation
-# of multiple instances of the Data class
-Data = Data2()