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RE: [dsdp-tm-dev] RE: SubSystemConfiguration vs. SubSystemFactory ??
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3) Yes.
All Services implement IService,
right?
So there could be an IServiceFactory
interface, implemented by
e.g. IFileService, ISearchService,
IRemoteCmdService, IShellService.
The extension point could support a list
of services to be contributed
to the configuration. The
SubSystemFactory (or the configuration?)
would be responsible for receiving
all configured factories, filtering
out those that are supported (through
instanceof), casting them to
the proper interfaces and installing
them.
The advantage of an ISubSystemConfiguration class, as
opposed to
doing everyting by extension point, would be that default
configurations
can be re-used more easily... the extension point would
need to list
all services for each and every configuration
again.
Hmm.... perhaps we'll end up with separate extension points
for the
factory and for the configuration eventually, with the
configuration being
totally UI-Less and the factory UI
dependent?
Cheers,
--
Martin Oberhuber
Target Management Project
Lead, DSDP PMC Member
http://www.eclipse.org/dsdp/tm
Hi Martin,
2) Okay, just means we'll need a few different types of
factories
3) So this extension point
would provide the means of specifying each of the factories involved?
We'd need to make it flexible enough to configuration additonal serivce
factories, depending on the factory type - like the
ISearchServiceFActory.
____________________________________
David McKnight
Phone: 905-413-3902 , T/L: 969-3902
Internet:
dmcknigh@xxxxxxxxxx
Mail:
D1/140/8200/TOR
____________________________________
| "Oberhuber, Martin"
<Martin.Oberhuber@xxxxxxxxxxxxx>
11/08/2006 10:25 AM
|
|
To
| David
McKnight/Toronto/IBM@IBMCA
|
|
cc
| "Target Management developer
discussions" <dsdp-tm-dev@xxxxxxxxxxx>
|
|
Subject
| RE: [dsdp-tm-dev] RE:
SubSystemConfiguration vs. SubSystemFactory
?? |
|
Hi Dave,
2) The point is that if you have a Configuration
create something, you
blow up the class, especially if you really want to just re-use an
existing factory.
It's better to delegate to what you already have.
3) Yes, I'm
suggesting a single extension point just for the configuration,
implying everything that
needs to be configured.
Cheers,
--
Martin Oberhuber
Target Management Project
Lead, DSDP PMC Member
http://www.eclipse.org/dsdp/tm
From: David McKnight
[mailto:dmcknigh@xxxxxxxxxx]
Sent: Friday, August 11, 2006 4:22
PM
To: Oberhuber, Martin
Cc: Target Management developer
discussions
Subject: RE: [dsdp-tm-dev] RE: SubSystemConfiguration
vs. SubSystemFactory ??
Hi Martin,
By the adapters, I don't mean the view adapters, I
mean the thing that takes a subsystem-independent IHostFile and wrappers it to
make it a subsystem-dependent IRemoteFile.
1) In RSE 7, there never was a
service, service adapter and all that replaceable stuff so the concepts have
changed slightly
2) Does a subsystem configuration really need to delegate -
wouldn't it know exactly what it needs to create? I mean, I don't see
the need for factories to be contributions to a configuration.
3) For this case are you
suggesting no extension point for the factory - just for the configuration,
implying the factory?
____________________________________
David McKnight
Phone: 905-413-3902 , T/L: 969-3902
Internet:
dmcknigh@xxxxxxxxxx
Mail:
D1/140/8200/TOR
____________________________________
| "Oberhuber, Martin"
<Martin.Oberhuber@xxxxxxxxxxxxx>
11/08/2006 09:58 AM
|
|
To
| David
McKnight/Toronto/IBM@IBMCA
|
|
cc
| "Target Management developer
discussions" <dsdp-tm-dev@xxxxxxxxxxx>
|
|
Subject
| RE: [dsdp-tm-dev] RE:
SubSystemConfiguration vs. SubSystemFactory
?? |
|
Hi
Dave,
I absolutely agree: There needs to be one place that holds all
these factories
together. Note that currently, these are _not_ all in one place
since the
RemoteElementAdapters are typically registered by the activator,
and not
by
the configuration.
The place that's holding all things together could
be
1.) The ISubSystemFactory class.
That's how it has been in RSE
7, the class has been renamed to ISubSystemConfiguration.
I don't like the
plain renaming because it's misleading.
2.) An
ISubSystemConfiguration class.
But then, the configuration should not
take on duties of the factory (by deriving from
the factory), but
it should delegate to the various factories where needed. That's
in-line
with the common best practice that "composition" of classes is usually
better
than "extending" classes in order to add
functionality.
3.) The subSystemConfiguration extension
point.
This would allow for plain "reconfiguration" of
existing services, by naming existing
factories where needed.
Compared to (2), it's basically the same pattern but moving
from a
programmatic approach to a data-driven approach. This might eventually
be helpful if we want to support headless (UI-less)
operation by instanciating only
service classes instead of the full-blown
UI-dependent classes from a headless
application.
I'm most
inclined towards (3), and I see the path towards it gradual: Leave
everything
in the factory for now (because this _is_ how things still work),
and split out the
various tasks into separate factories or a configuration
class gradually.
Thanks for your thoughts and discussion!
I consider this really
exciting and helpful.
Thanks,
--
Martin Oberhuber
Target Management Project
Lead, DSDP PMC Member
http://www.eclipse.org/dsdp/tm
From: dsdp-tm-dev-bounces@xxxxxxxxxxx
[mailto:dsdp-tm-dev-bounces@xxxxxxxxxxx] On Behalf Of David
McKnight
Sent: Friday, August 11, 2006 3:16 PM
To:
Oberhuber, Martin
Cc: Target Management developer
discussions
Subject: RE: [dsdp-tm-dev] RE: SubSystemConfiguration
vs. SubSystemFactory ??
Hi Martin,
So do you think we'd need an IServiceFactory for the
configuration? If we start down that path, then we also need
IConnectorServiceFactory, and then depending on the underlying model, we'd
need something to create service model to subsystem model adapters, such as
IHostFileToRemoteFileAdapter, which
converts IHostFile to IRemoteFile. The other thing is that some
subsystems have additional services, such as the ISearchService for files -
would that just be created from the IServiceFactory? For each of these
factories, we'd still need one object to hold them altogether so that there's
a clean switch when you change from one configuration to another for a given
subsystem. The concept of service didn't exist when the documentation
was written, so I'm not sure it buys us that much there if we role up the
configuration into the factory.
____________________________________
David
McKnight
Phone: 905-413-3902 , T/L:
969-3902
Internet: dmcknigh@xxxxxxxxxx
Mail:
D1/140/8200/TOR
____________________________________
| "Oberhuber, Martin"
<Martin.Oberhuber@xxxxxxxxxxxxx>
11/08/2006 08:52 AM
|
|
To
| David
McKnight/Toronto/IBM@IBMCA
|
|
cc
| "Target Management developer
discussions" <dsdp-tm-dev@xxxxxxxxxxx>
|
|
Subject
| RE: [dsdp-tm-dev] RE:
SubSystemConfiguration vs. SubSystemFactory
?? |
|
Hi
Dave,
I
thought about your suggestion again.
We'll probably need a bit more time to sort
out the actual details of separating
ISubSystemConfiguration from
ISubSystemFactory. What's important for me,
though, is that whenever a class is
responsible for creating something, I'd like
to name it
"...Factory".
Bringing back the name ISubSystemFactory instead of
ISubSystemConfiguration,
for what essentially _is_ a factory, has the very big
advantage that all documentation
referring to ...factories would be correct again. And
that's a lot!!
For me it looks like even if a user re-uses an existing
FileServiceSubSystemFactory,
he'd supply his own IFileService. In other words, the
configuration would need to name
a factory for creating IFileService objects, wouldn't
it?
The
extension point, finally, names a "type" or "configuration" of subsystem.
Elements
of
the extension point (which is a configuration) can be the ISubSystemFactory
class,
the
IConnectorService class, and the IServiceFactory class. Such an extension
point
would (I think) make the duplicate code for the current factories
eventually unnecessary,
and all the "plumbing" of the configuration would occur via the
extension point.
The extension point would be the "configuration" but it would
name the factory
classes which are responsible for creating objects of
proper type.
This would also be a little bit in line with what the Platform does
for
extension points
org.eclipse.update.core.featureTypes --> element
<feature-factory>
org.eclipse.update.core.siteTypes --> element
<site-factory>
I
suggest we go ahead with renaming classes accordingly for now. I'll send
out
a
separate E-mail with requested refactorings. We can think about the split-up
later on if we want -- it would affect the code much less than doing all
at once,
since it would just be one additional item in the extension
point.
How does that sound?
Cheers,
--
Martin Oberhuber
Target Management Project
Lead, DSDP PMC Member
http://www.eclipse.org/dsdp/tm
From: dsdp-tm-dev-bounces@xxxxxxxxxxx
[mailto:dsdp-tm-dev-bounces@xxxxxxxxxxx] On Behalf Of Martin
Oberhuber
Sent: Thursday, August 10, 2006 10:19 PM
To:
David McKnight
Cc: Target Management developer
discussions
Subject: Re: [dsdp-tm-dev] RE: SubSystemConfiguration
vs. SubSystemFactory ??
Hi Dave,
ahh, now I
see! Your suggestion sounds excellent.
I guess there's still a few
things to sort out, like where does the ConnectorService come from (would
there be
ISubSystemConfiguration.getConnectorService()?
Then, what about
methods like supportsFilters() which are more a static configuration property
than a dynamic one and thus be more associated with the factory, than the
actual config -- after all they define capabilities of the subsystem
implementation, and not its actual configuration.
Finally, the
extension point... should the extension point name both the config and the
factory classes?
Or should the config have a method like
getSubSystemFactory()?
For me it sounds like the config is "above" the
factory, it's like the master putting all items
together.
Cheers,
Martin
David McKnight schrieb:
I'm seeing the value of the
configuration not so much for things like "isCaseSensitive" but for providing
the actual service implementations. We define the FileServiceSubSystem
independently of any service implementation. Currently the means of
providing each service implementation is via each the subsystem configuration
however each is also the thign that creates the subsystem. Each
subsystem configuration does some redundant thing - they each create
FileServiceSubSystem. RSE does allow you to switch configurations and
thus thus services such that the subsystem configuration that was intially
used to create the subsystem would no longer be used after a subsystem
configuration gets switched, which is kind of weird. That problem would
be solved with an independent factory.
If no subsystem configurations are contributed
then there would never been a subsystem to create, so I don't see the value of
having a default configuration. I guess I'm sort of thinking along these
lines:
class FileServiceSubSystemFactory implements ISubSystemFactory
{
public
ISubSystem createSubSystemInternal(ISubSystemConfiguration
initialConfiguration) {
return new FileServiceSubSystem(
initialConfiguration, ... );
}
}
There would never be an SshFileServieSubSystem, nor a
DStoreFileServiceSubSystem - there's only FileServiceSubSystem with a
configuration that provides the service implementation.
class
SshSubSystemConfiguration implements ISubSystemConfiguration {
public
boolean isCaseSensitive() { return true; }
public IFileService
getFileService(IHost host);
....
}
Does that make any
sense?
____________________________________
David McKnight
Phone: 905-413-3902 , T/L: 969-3902
Internet:
dmcknigh@xxxxxxxxxx
Mail:
D1/140/8200/TOR
____________________________________
Hi
Dave,
I'm afraid I cannot follow you thoroughly.
I didn't think about
contributing the configuration and the factory separately, but
only provide an
extension point for the factory. The factory would be responsible
for creating the
subsystem, and its initial configuration. I wouldn't see what the
advantage of separate contributions for configuration and factory would
be.
We probably shouldn't deviate from what we currently have too much
right now.
Currently, we have a static configuration that is tied 1:1 to the
factory. With my
proposed change, the factory could provide configurations that are
not so much
tied to it any more, and thus more flexible.
I didn't think about
persisting modified configurations though, so allowing
configurations to
change at runtime is probably something to consider for
2.0 (and keeping them static for
now).
Perhaps an example could help:
class SshSubSystemFactory
implements ISubSystemFactory {
public ISubSystem createSubSystemInternal()
{
return new SshSubSystem( getDefaultConfiguration(), ... );
}
public
ISubSystemConfiguration getDefaultConfiguration {
//the
configuration can be an anonymous inner class,
//or a real
class defined outside
return new DefaultSubSystemConfiguration
{
// define overriders here
public boolean isCaseSensitive() { return true; }
}
}
}
Or, if we want to keep
code closer to what it is right now:
class SshSubSystemFactory implements
ISubSystemFactory, ISubSystemConfiguration {
public ISubSystem createSubSystemInternal()
{
return new SshSubSystem( this, ... );
}
public boolean isCaseSensitive() { return true;
}
}
In both cases, the Subsystem can replace its current
configuration with
something different later on.
Another option, for DStore
for instance, would be to have
class DStoreWindowsSubSystemConfiguration extends
DefaultSubSystemConfiguration {
public boolean isCaseSensitive() { return true;
}
}
class DStoreUnixSubSystemConfiguration extends
DefaultSubSystemConfiguration {
public boolean isCaseSensitive() { return false;
}
}
Comments?
Cheers,
--
Martin Oberhuber
Target Management Project
Lead, DSDP PMC Member
http://www.eclipse.org/dsdp/tm
From: dsdp-tm-dev-bounces@xxxxxxxxxxx [mailto:dsdp-tm-dev-bounces@xxxxxxxxxxx] On Behalf Of David McKnight
Sent:
Thursday, August 10, 2006 5:01 PM
To: David Dykstal
Cc:
Oberhuber, Martin; Target Management developer discussions
Subject:
[dsdp-tm-dev] RE: SubSystemConfiguration vs. SubSystemFactory ??
I like the idea but I'm thinking that it
would be good to still keep the service creation with the configuration rather
than the factory. There could be a single factory for each different
type of service subsystem:
Example:
FileServiceSubSystemFactory --> produces
--> FileServiceSubSystem
ShellServiceSubSystemFactory --> produces -->
ShellServiceSubSystem
ProcessServiceSubSystemFactory --> produces -->
ProcessServiceSubSystem
...
The factory would be responsible for the lifecycle of the
subsystem but would use the configuration to define, not only the attributes
in terms of "isCaseSensitive()" and such but also the services themselves.
The factory could use the the current to setup the service
configuration for a subsystem. For each, service there could be a
different configuration:
Example:
DStoreFileServiceConfiguration
SSHFileServiceConfguration
FTPFileServiceConfiguration
A given factory may use one of the
available configurations for creating the subsystem as well as changing it's
configuration - for example, when switching between FTP and
DStore.
If we
were to take this approach, we could keep the configuration extension point
pretty much the same - since it's really there to contribute the services, but
we'd need to introduce a new extension point for the subsystem factory.
So there would be a FileServiceSubSystemFactory contribution before any
service configurations are defined.
What do you think of this?
____________________________________
David McKnight
Phone: 905-413-3902 , T/L: 969-3902
Internet:
dmcknigh@xxxxxxxxxx
Mail:
D1/140/8200/TOR
____________________________________
| David
Dykstal/Rochester/IBM@IBMUS
10/08/2006 10:13 AM
|
|
Interesting
idea.
In most
cases where we have to grab the SubSystemConfiguration from the subsystem we
would continue to do so. So its possible this won't be as bad as I
initially suspected. This is a pretty pervasive hit though and it affects the
extension points. Would you expect to define both subystem factory and
subsystem configuration extension points independently or would a subsystem
factory provide a subsystem configuration to the subsystems it
creates?
_______________________
David Dykstal
david_dykstal@xxxxxxxxxx
