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Posted to dev@tuscany.apache.org by Simon Laws <si...@googlemail.com> on 2007/08/09 18:51:04 UTC
Accessing global domain information
I need some advice on the way the code is structures. In various places in
the code I need to get at some information that logically belongs to the sca
domain. For example,
CompositeWireBuilderImpl.connectComponentReferences()
Tries to resolve services. In the distributed case this resolution may
validly fail and I need to ask the domain whether the service is available
elsewhere. So I need access to some domain management services. Ideally I
would like to have access to a domain interface but am unsure how to plumb
it in as this kind of thing isn't generally available now. Anyone care to
offer some advice how I get at such an interface without breaking the SPIs?
Thanks
Simon
Re: Accessing global domain information
Posted by Jean-Sebastien Delfino <js...@apache.org>.
Simon Laws wrote:
> On 8/10/07, Raymond Feng <en...@gmail.com> wrote:
>
>> Comments inline.
>>
>> Thanks,
>> Raymond
>> ----- Original Message -----
>> From: "Simon Laws" <si...@googlemail.com>
>> To: <tu...@ws.apache.org>
>> Sent: Thursday, August 09, 2007 3:46 PM
>> Subject: Re: Accessing global domain information
>>
>>
>>
>>> On 8/9/07, Simon Laws <si...@googlemail.com> wrote:
>>>
>>>>
>>>> On 8/9/07, Jean-Sebastien Delfino <jsdelfino@apache.org > wrote:
>>>>
>>>>> Simon Laws wrote:
>>>>>
>>>>>> I need some advice on the way the code is structures. In various
>>>>>>
>>>>> places in
>>>>>
>>>>>> the code I need to get at some information that logically belongs
>>>>>>
>> to
>>
>>>>> the sca
>>>>>
>>>>>> domain. For example,
>>>>>>
>>>>>> CompositeWireBuilderImpl.connectComponentReferences()
>>>>>>
>>>>>> Tries to resolve services. In the distributed case this resolution
>>>>>> may
>>>>>> validly fail and I need to ask the domain whether the service is
>>>>>>
>>>>> available
>>>>>
>>>>>> elsewhere. So I need access to some domain management services.
>>>>>>
>>>>> Ideally I
>>>>>
>>>>>> would like to have access to a domain interface but am unsure how
>>>>>>
>> to
>>
>>>>> plumb
>>>>>
>>>>>> it in as this kind of thing isn't generally available now. Anyone
>>>>>> care
>>>>>>
>>>>> to
>>>>>
>>>>>> offer some advice how I get at such an interface without breaking
>>>>>>
>> the
>>
>>>>> SPIs?
>>>>>
>>>>>> Thanks
>>>>>>
>>>>>> Simon
>>>>>>
>>>>>>
>>>>>>
>>>>> WireCompositeBuilderImpl is not an SPI, so you can pass whatever you
>>>>> want to its constructor without breaking any SPI.
>>>>>
>>>>> But I have a preliminary question: Why do you need to ask the domain
>>>>> (management service) about remote services at that specific point in
>>>>> WireCompositeBuilderImpl?
>>>>>
>>>>> --
>>>>> Jean-Sebastien
>>>>>
>>>>>
>>>>> ---------------------------------------------------------------------
>>>>> To unsubscribe, e-mail: tuscany-dev-unsubscribe@ws.apache.org
>>>>> For additional commands, e-mail: tuscany-dev-help@ws.apache.org
>>>>>
>>>>> Hi Sebastien
>>>>>
>>>> I was thinking about this on the drive home. Just looking back at the
>>>> code
>>>> I had missed the important point that a reference target remains
>>>> unresolved
>>>> if the target component cannot be found. I could use this instead of
>>>>
>> the
>>
>>>> actual service lookup at this point. The issue I have though is that
>>>>
>> the
>>
>>>> CompositeWireBuilder dumps the bindings from the reference if it can't
>>>> find
>>>> a matching service/binding. This will be the case if the model for the
>>>> references service/binding is not read into the model for the current
>>>> node,
>>>> i.e. if the target component is not included in the current nodes
>>>> contributions.
>>>>
>>>> Is it valid to only replace the current bindings with
>>>>
>> "selectedBindings"
>>
>>>> if some selected bindings have actually be found?
>>>>
>>>> Simon
>>>>
>>>>
>>> Have been looking into this a little more and it seems that the list of
>>> matched bindings takes into account the reference multiplicities and
>>>
>> then
>>
>>> is
>>> used during activation to create the runtime wires so we do have to be a
>>> little cleverer in terms of creating a dummy resolved target to keep the
>>> bindings in play.
>>>
>>>
>> Let's assume the reference is wired to a remote SCA service for this
>> discussion. For non-SCA services, it's simpler as we just have to pick a
>> binding locally for the reference and the binding URI will be good enough
>> for the routing.
>>
>> There are two factors here:
>>
>> 1) What information is required from the service side for the reference
>> side
>> to choose the right binding?
>>
>> service: {service uri in the domain, a list of bindings} (I intentionally
>> skip the intent/policy stuff here). The key is that should be able to
>> build
>> a call routing to this service endpoint.
>>
>> 2) When should we try to do the matching between the reference and the
>> service?
>>
>> In some cases, the remote service information is not available when the
>> runtime wires are constructed. It means we have to defer the process when
>> the reference is used.
>>
>>
>>> Anyone out there intimately familiar with the resolution process? What I
>>> want to be able to do is have an sca binding (or any other binding for
>>> that
>>> matter) remain in place even in the case where the referenced target is
>>> not
>>> available in the local domain composite. Come runtime wire generation
>>>
>> time
>>
>>> the binding itself can take responsibility for creating the correct
>>> providers and invokers so that, assuming the referenced service is
>>> remoteable, the request can be routed to the correct node.
>>>
>>> Simon
>>>
>>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: tuscany-dev-unsubscribe@ws.apache.org
>> For additional commands, e-mail: tuscany-dev-help@ws.apache.org
>>
>> Thanks Raymond, I'm with you there. I'm not sure whether you are agreeing
>>
> or disagreeing that maintaining the list of unresolved targets will be
> problematic. I'm going ahead on the basis that we need to maintain the list,
> i.e. I'll change
>
> if (!targets.isEmpty() &&) {
> // Add all the effective bindings
>
> to
>
> if (!targets.isEmpty() &&
> !selectedBindings.isEmpty()) {
> // Add all the effective bindings
>
> at the bottom of
>
> CompositeWireBuilderImpl.connectComponentReferences()
>
> and see how I get on. In this way the candidate bindings hang around until
> later on in the case that the targets are unresolved.
>
> Simon
>
>
+1 yes the candidate bindings need to hang around until later when the
targets get eventually resolved.
--
Jean-Sebastien
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Re: Accessing global domain information
Posted by Simon Laws <si...@googlemail.com>.
On 8/10/07, Raymond Feng <en...@gmail.com> wrote:
>
> Comments inline.
>
> Thanks,
> Raymond
> ----- Original Message -----
> From: "Simon Laws" <si...@googlemail.com>
> To: <tu...@ws.apache.org>
> Sent: Thursday, August 09, 2007 3:46 PM
> Subject: Re: Accessing global domain information
>
>
> > On 8/9/07, Simon Laws <si...@googlemail.com> wrote:
> >>
> >>
> >>
> >> On 8/9/07, Jean-Sebastien Delfino <jsdelfino@apache.org > wrote:
> >> >
> >> > Simon Laws wrote:
> >> > > I need some advice on the way the code is structures. In various
> >> > places in
> >> > > the code I need to get at some information that logically belongs
> to
> >> > the sca
> >> > > domain. For example,
> >> > >
> >> > > CompositeWireBuilderImpl.connectComponentReferences()
> >> > >
> >> > > Tries to resolve services. In the distributed case this resolution
> >> > > may
> >> > > validly fail and I need to ask the domain whether the service is
> >> > available
> >> > > elsewhere. So I need access to some domain management services.
> >> > Ideally I
> >> > > would like to have access to a domain interface but am unsure how
> to
> >> > plumb
> >> > > it in as this kind of thing isn't generally available now. Anyone
> >> > > care
> >> > to
> >> > > offer some advice how I get at such an interface without breaking
> the
> >> > SPIs?
> >> > >
> >> > > Thanks
> >> > >
> >> > > Simon
> >> > >
> >> > >
> >> > WireCompositeBuilderImpl is not an SPI, so you can pass whatever you
> >> > want to its constructor without breaking any SPI.
> >> >
> >> > But I have a preliminary question: Why do you need to ask the domain
> >> > (management service) about remote services at that specific point in
> >> > WireCompositeBuilderImpl?
> >> >
> >> > --
> >> > Jean-Sebastien
> >> >
> >> >
> >> > ---------------------------------------------------------------------
> >> > To unsubscribe, e-mail: tuscany-dev-unsubscribe@ws.apache.org
> >> > For additional commands, e-mail: tuscany-dev-help@ws.apache.org
> >> >
> >> > Hi Sebastien
> >>
> >> I was thinking about this on the drive home. Just looking back at the
> >> code
> >> I had missed the important point that a reference target remains
> >> unresolved
> >> if the target component cannot be found. I could use this instead of
> the
> >> actual service lookup at this point. The issue I have though is that
> the
> >> CompositeWireBuilder dumps the bindings from the reference if it can't
> >> find
> >> a matching service/binding. This will be the case if the model for the
> >> references service/binding is not read into the model for the current
> >> node,
> >> i.e. if the target component is not included in the current nodes
> >> contributions.
> >>
> >> Is it valid to only replace the current bindings with
> "selectedBindings"
> >> if some selected bindings have actually be found?
> >>
> >> Simon
> >>
> > Have been looking into this a little more and it seems that the list of
> > matched bindings takes into account the reference multiplicities and
> then
> > is
> > used during activation to create the runtime wires so we do have to be a
> > little cleverer in terms of creating a dummy resolved target to keep the
> > bindings in play.
> >
>
> Let's assume the reference is wired to a remote SCA service for this
> discussion. For non-SCA services, it's simpler as we just have to pick a
> binding locally for the reference and the binding URI will be good enough
> for the routing.
>
> There are two factors here:
>
> 1) What information is required from the service side for the reference
> side
> to choose the right binding?
>
> service: {service uri in the domain, a list of bindings} (I intentionally
> skip the intent/policy stuff here). The key is that should be able to
> build
> a call routing to this service endpoint.
>
> 2) When should we try to do the matching between the reference and the
> service?
>
> In some cases, the remote service information is not available when the
> runtime wires are constructed. It means we have to defer the process when
> the reference is used.
>
> > Anyone out there intimately familiar with the resolution process? What I
> > want to be able to do is have an sca binding (or any other binding for
> > that
> > matter) remain in place even in the case where the referenced target is
> > not
> > available in the local domain composite. Come runtime wire generation
> time
> > the binding itself can take responsibility for creating the correct
> > providers and invokers so that, assuming the referenced service is
> > remoteable, the request can be routed to the correct node.
> >
> > Simon
> >
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: tuscany-dev-unsubscribe@ws.apache.org
> For additional commands, e-mail: tuscany-dev-help@ws.apache.org
>
> Thanks Raymond, I'm with you there. I'm not sure whether you are agreeing
or disagreeing that maintaining the list of unresolved targets will be
problematic. I'm going ahead on the basis that we need to maintain the list,
i.e. I'll change
if (!targets.isEmpty() &&) {
// Add all the effective bindings
to
if (!targets.isEmpty() &&
!selectedBindings.isEmpty()) {
// Add all the effective bindings
at the bottom of
CompositeWireBuilderImpl.connectComponentReferences()
and see how I get on. In this way the candidate bindings hang around until
later on in the case that the targets are unresolved.
Simon
Re: Accessing global domain information
Posted by Raymond Feng <en...@gmail.com>.
Comments inline.
Thanks,
Raymond
----- Original Message -----
From: "Simon Laws" <si...@googlemail.com>
To: <tu...@ws.apache.org>
Sent: Thursday, August 09, 2007 3:46 PM
Subject: Re: Accessing global domain information
> On 8/9/07, Simon Laws <si...@googlemail.com> wrote:
>>
>>
>>
>> On 8/9/07, Jean-Sebastien Delfino <jsdelfino@apache.org > wrote:
>> >
>> > Simon Laws wrote:
>> > > I need some advice on the way the code is structures. In various
>> > places in
>> > > the code I need to get at some information that logically belongs to
>> > the sca
>> > > domain. For example,
>> > >
>> > > CompositeWireBuilderImpl.connectComponentReferences()
>> > >
>> > > Tries to resolve services. In the distributed case this resolution
>> > > may
>> > > validly fail and I need to ask the domain whether the service is
>> > available
>> > > elsewhere. So I need access to some domain management services.
>> > Ideally I
>> > > would like to have access to a domain interface but am unsure how to
>> > plumb
>> > > it in as this kind of thing isn't generally available now. Anyone
>> > > care
>> > to
>> > > offer some advice how I get at such an interface without breaking the
>> > SPIs?
>> > >
>> > > Thanks
>> > >
>> > > Simon
>> > >
>> > >
>> > WireCompositeBuilderImpl is not an SPI, so you can pass whatever you
>> > want to its constructor without breaking any SPI.
>> >
>> > But I have a preliminary question: Why do you need to ask the domain
>> > (management service) about remote services at that specific point in
>> > WireCompositeBuilderImpl?
>> >
>> > --
>> > Jean-Sebastien
>> >
>> >
>> > ---------------------------------------------------------------------
>> > To unsubscribe, e-mail: tuscany-dev-unsubscribe@ws.apache.org
>> > For additional commands, e-mail: tuscany-dev-help@ws.apache.org
>> >
>> > Hi Sebastien
>>
>> I was thinking about this on the drive home. Just looking back at the
>> code
>> I had missed the important point that a reference target remains
>> unresolved
>> if the target component cannot be found. I could use this instead of the
>> actual service lookup at this point. The issue I have though is that the
>> CompositeWireBuilder dumps the bindings from the reference if it can't
>> find
>> a matching service/binding. This will be the case if the model for the
>> references service/binding is not read into the model for the current
>> node,
>> i.e. if the target component is not included in the current nodes
>> contributions.
>>
>> Is it valid to only replace the current bindings with "selectedBindings"
>> if some selected bindings have actually be found?
>>
>> Simon
>>
> Have been looking into this a little more and it seems that the list of
> matched bindings takes into account the reference multiplicities and then
> is
> used during activation to create the runtime wires so we do have to be a
> little cleverer in terms of creating a dummy resolved target to keep the
> bindings in play.
>
Let's assume the reference is wired to a remote SCA service for this
discussion. For non-SCA services, it's simpler as we just have to pick a
binding locally for the reference and the binding URI will be good enough
for the routing.
There are two factors here:
1) What information is required from the service side for the reference side
to choose the right binding?
service: {service uri in the domain, a list of bindings} (I intentionally
skip the intent/policy stuff here). The key is that should be able to build
a call routing to this service endpoint.
2) When should we try to do the matching between the reference and the
service?
In some cases, the remote service information is not available when the
runtime wires are constructed. It means we have to defer the process when
the reference is used.
> Anyone out there intimately familiar with the resolution process? What I
> want to be able to do is have an sca binding (or any other binding for
> that
> matter) remain in place even in the case where the referenced target is
> not
> available in the local domain composite. Come runtime wire generation time
> the binding itself can take responsibility for creating the correct
> providers and invokers so that, assuming the referenced service is
> remoteable, the request can be routed to the correct node.
>
> Simon
>
---------------------------------------------------------------------
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For additional commands, e-mail: tuscany-dev-help@ws.apache.org
Re: Accessing global domain information
Posted by Simon Laws <si...@googlemail.com>.
On 8/9/07, Simon Laws <si...@googlemail.com> wrote:
>
>
>
> On 8/9/07, Jean-Sebastien Delfino <jsdelfino@apache.org > wrote:
> >
> > Simon Laws wrote:
> > > I need some advice on the way the code is structures. In various
> > places in
> > > the code I need to get at some information that logically belongs to
> > the sca
> > > domain. For example,
> > >
> > > CompositeWireBuilderImpl.connectComponentReferences()
> > >
> > > Tries to resolve services. In the distributed case this resolution may
> > > validly fail and I need to ask the domain whether the service is
> > available
> > > elsewhere. So I need access to some domain management services.
> > Ideally I
> > > would like to have access to a domain interface but am unsure how to
> > plumb
> > > it in as this kind of thing isn't generally available now. Anyone care
> > to
> > > offer some advice how I get at such an interface without breaking the
> > SPIs?
> > >
> > > Thanks
> > >
> > > Simon
> > >
> > >
> > WireCompositeBuilderImpl is not an SPI, so you can pass whatever you
> > want to its constructor without breaking any SPI.
> >
> > But I have a preliminary question: Why do you need to ask the domain
> > (management service) about remote services at that specific point in
> > WireCompositeBuilderImpl?
> >
> > --
> > Jean-Sebastien
> >
> >
> > ---------------------------------------------------------------------
> > To unsubscribe, e-mail: tuscany-dev-unsubscribe@ws.apache.org
> > For additional commands, e-mail: tuscany-dev-help@ws.apache.org
> >
> > Hi Sebastien
>
> I was thinking about this on the drive home. Just looking back at the code
> I had missed the important point that a reference target remains unresolved
> if the target component cannot be found. I could use this instead of the
> actual service lookup at this point. The issue I have though is that the
> CompositeWireBuilder dumps the bindings from the reference if it can't find
> a matching service/binding. This will be the case if the model for the
> references service/binding is not read into the model for the current node,
> i.e. if the target component is not included in the current nodes
> contributions.
>
> Is it valid to only replace the current bindings with "selectedBindings"
> if some selected bindings have actually be found?
>
> Simon
>
Have been looking into this a little more and it seems that the list of
matched bindings takes into account the reference multiplicities and then is
used during activation to create the runtime wires so we do have to be a
little cleverer in terms of creating a dummy resolved target to keep the
bindings in play.
Anyone out there intimately familiar with the resolution process? What I
want to be able to do is have an sca binding (or any other binding for that
matter) remain in place even in the case where the referenced target is not
available in the local domain composite. Come runtime wire generation time
the binding itself can take responsibility for creating the correct
providers and invokers so that, assuming the referenced service is
remoteable, the request can be routed to the correct node.
Simon
Re: Accessing global domain information
Posted by Simon Laws <si...@googlemail.com>.
On 8/9/07, Jean-Sebastien Delfino <js...@apache.org> wrote:
>
> Simon Laws wrote:
> > I need some advice on the way the code is structures. In various places
> in
> > the code I need to get at some information that logically belongs to the
> sca
> > domain. For example,
> >
> > CompositeWireBuilderImpl.connectComponentReferences()
> >
> > Tries to resolve services. In the distributed case this resolution may
> > validly fail and I need to ask the domain whether the service is
> available
> > elsewhere. So I need access to some domain management services. Ideally
> I
> > would like to have access to a domain interface but am unsure how to
> plumb
> > it in as this kind of thing isn't generally available now. Anyone care
> to
> > offer some advice how I get at such an interface without breaking the
> SPIs?
> >
> > Thanks
> >
> > Simon
> >
> >
> WireCompositeBuilderImpl is not an SPI, so you can pass whatever you
> want to its constructor without breaking any SPI.
>
> But I have a preliminary question: Why do you need to ask the domain
> (management service) about remote services at that specific point in
> WireCompositeBuilderImpl?
>
> --
> Jean-Sebastien
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: tuscany-dev-unsubscribe@ws.apache.org
> For additional commands, e-mail: tuscany-dev-help@ws.apache.org
>
> Hi Sebastien
I was thinking about this on the drive home. Just looking back at the code I
had missed the important point that a reference target remains unresolved if
the target component cannot be found. I could use this instead of the actual
service lookup at this point. The issue I have though is that the
CompositeWireBuilder dumps the bindings from the reference if it can't find
a matching service/binding. This will be the case if the model for the
references service/binding is not read into the model for the current node,
i.e. if the target component is not included in the current nodes
contributions.
Is it valid to only replace the current bindings with "selectedBindings" if
some selected bindings have actually be found?
Simon
Re: Accessing global domain information
Posted by Jean-Sebastien Delfino <js...@apache.org>.
Simon Laws wrote:
> I need some advice on the way the code is structures. In various places in
> the code I need to get at some information that logically belongs to the sca
> domain. For example,
>
> CompositeWireBuilderImpl.connectComponentReferences()
>
> Tries to resolve services. In the distributed case this resolution may
> validly fail and I need to ask the domain whether the service is available
> elsewhere. So I need access to some domain management services. Ideally I
> would like to have access to a domain interface but am unsure how to plumb
> it in as this kind of thing isn't generally available now. Anyone care to
> offer some advice how I get at such an interface without breaking the SPIs?
>
> Thanks
>
> Simon
>
>
WireCompositeBuilderImpl is not an SPI, so you can pass whatever you
want to its constructor without breaking any SPI.
But I have a preliminary question: Why do you need to ask the domain
(management service) about remote services at that specific point in
WireCompositeBuilderImpl?
--
Jean-Sebastien
---------------------------------------------------------------------
To unsubscribe, e-mail: tuscany-dev-unsubscribe@ws.apache.org
For additional commands, e-mail: tuscany-dev-help@ws.apache.org