Prasanna - What you raise is a very interesting point. But this would be an
issue only in some of the ServerResources where implementation is like below
code. Here there is no exact match of the class and hence it can get into the
implementation of its parent unless the order is maintained.
So if someone sends RebootRouterCommand which lets say hypothetically is
subclass of StopCommand then the execute((StopCommand) cmd gets executed here.
It's important to maintain order just like we catch exceptions keeping the most
generalized classes in the end.
if (cmd instanceof StopCommand) {
return execute((StopCommand) cmd);
} else if (cmd instanceof GetVmStatsCommand) {
return execute((GetVmStatsCommand) cmd);
} else if (cmd instanceof RebootRouterCommand) {
return execute((RebootRouterCommand) cmd);
Ideally the implementations of ServerResources should be like this. Example -
CitrixResourceBase.java so that there is an exact match of the command.
Class<? extends Command> clazz = cmd.getClass();
if (clazz == CreateCommand.class) {
return execute((CreateCommand) cmd);
} else if (clazz == SetPortForwardingRulesCommand.class) {
return execute((SetPortForwardingRulesCommand)
cmd);
I think it's a bug.
Thanks,
-Nitin
-----Original Message-----
From: Prasanna Santhanam [mailto:[email protected]]
Sent: Thursday, August 02, 2012 4:28 PM
To: CloudStack Dev
Subject: PrepareForMigrationCommand subtype of StartCommand
In the Command type hierarchy the PrepareForMigrationCommand extends a
StartCommand.
In my mind, StartCommand is intended for VMs to be started where as
PrepareForMigrationCommand is for hosts. Most of the ServerResources implement
PrepareForMigrationCommand before StartCommand and so we don't seem to be
hitting any issues.
Is this intended or a bug? If intended - can someone explain why?
Thanks,
--
Prasanna.,
