Hi,
Is transaction build in of ZODB? I have a product which keep a counter
property and a inc method which will increase the property with a integer
amount. I would like to make sure that concurrent inc call will not cause
problem. Is ZODB automatically do transaction and prevent corrupt of data?
My class is like this:
class Cid(
OFS.SimpleItem.Item, # A simple Principia object. Not Folderish.
Persistent, # Make us persistent. Yaah!
Acquisition.Implicit, # Uh, whatever.
AccessControl.Role.RoleManager # Security manager.
):
"""Cid object.
Keep an integer value and provide an way to inc it.
"""
meta_type = 'Cid' # what do people think they're adding?
manage_options = ( # what management options are there?
{'label': 'Edit', 'action': 'manage_main'},
{'label': 'View', 'action': ''}, # defaults to index_html
{'label': 'Security', 'action': 'manage_access'},
)
__ac_permissions__=( # what permissions make sense for us?
('View management screens', ('manage_tabs','manage_main')),
('Change permissions', ('manage_access',) ),
('Change Cid' , ('manage_edit',) ),
('View Cid', ('',) ),
)
def __init__(self, id, title='', initval=0):
"""initialise a new instance"""
self.id = id
self.title = title
try:
self.counter = int(initval)
except:
self.counter= 0
def inc(self, increment=1):
""" inc counter """
self.counter = self.counter+increment
return
def __repr__(self):
'''aa'''
return self.counter
def __str__(self):
''' a '''
return str(self.counter)
def index_html(self):
''' return data '''
return self.counter
manage_main = HTMLFile('CidEdit', globals()) # Management Interface
def manage_edit(self, title, counter, REQUEST=None):
"""does this really need a doc string?"""
self.title = title
try:
self.counter = int(counter)
except:
pass
if REQUEST is not None:
return MessageDialog(
title = 'Edited',
message = "Properties for %s changed." % self.id,
action = './manage_main',
)
I add an object aaa of Cid and make the following call on dtml:
<dtml-call "aaa.inc()">
Counter is now : <dtml-var aaa>
How could I prevent aaa get updated after inc() is call?
Rgs,
Kent Sin
---------------------------------
kentsin.weblogs.com
kentsin.imeme.net
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