Question about attribute mustSupply

[Shuchao Wan <wa...@gmail.com>]

Hi, Guys,

I have some questions about <Property> attribute mustSupply, would you like
to help me with them. Thanks in advance.

1. mustSupply is one of attributes of element Property, it is used to
indicate that the property value must be supplied by components that uses
the implementation. So my understanding is that there are only two places we
can set this attribute. One is the child elment of <componentType>, the
other is the child element of <composite> where the composite is utilized as
component implementation. That is to say, mustSupply shouldn't be one of
attribute of <component>'s <Property>. Am I right?

2. If mustSupply is specified as true, while the user doesn't provide any
property value, what will happen?  Any expection will be thrown? It is
strange that I didn't see any warning message or expection in my test.

3. I'm not very sure about the meaning of ASM60034. It says that "For a
composite used as a component implementation, all properties of components
within the composite, where the underlying component implementation
specifies "mustSupply=true" for the property, MUST either *specify a value
for the property* or source the value from a composite property. "  I know
how to specify the source value, but how to specify the value for the
property?  Does it mean a default value? However, in composite chapter of
specification, it says that "when mustSupply="true" the component has to
supply a value since the composite has no default value for the property. "

Re: Question about attribute mustSupply

[Simon Laws <si...@googlemail.com>]

Hi

On Thu, Feb 26, 2009 at 7:29 AM, Shuchao Wan <wa...@gmail.com> wrote:

> Hi, Guys,
>
> I have some questions about <Property> attribute mustSupply, would you like
> to help me with them. Thanks in advance.
>
> 1. mustSupply is one of attributes of element Property, it is used to
> indicate that the property value must be supplied by components that uses
> the implementation. So my understanding is that there are only two places we
> can set this attribute. One is the child elment of <componentType>, the
> other is the child element of <composite> where the composite is utilized as
> component implementation. That is to say, mustSupply shouldn't be one of
> attribute of <component>'s <Property>. Am I right?
>
>

Sounds right to me. There is an editorial error in the OASIS spec where this
attribute appears in the component property pseudo schema when it shouldn't


> 2. If mustSupply is specified as true, while the user doesn't provide any
> property value, what will happen?  Any expection will be thrown? It is
> strange that I didn't see any warning message or expection in my test.
>

I would expect an error to be raised as the composite is in error.


>
> 3. I'm not very sure about the meaning of ASM60034. It says that "For a
> composite used as a component implementation, all properties of components
> within the composite, where the underlying component implementation
> specifies "mustSupply=true" for the property, MUST either *specify a value
> for the property* or source the value from a composite property. "  I know
> how to specify the source value, but how to specify the value for the
> property?  Does it mean a default value? However, in composite chapter of
> specification, it says that "when mustSupply="true" the component has to
> supply a value since the composite has no default value for the property. "
>
>
>

There is a hierarchy implied here and two different scenarios I think;

Scenario- components in composites
----------------------------------------------------

composite
   component
       implementation.composite
           composite
               property name="prop1" VALUE SUPPLIED HERE
               component
                   property mustSupply="true" source="$prop1"


Scenario - composites as component implementations
----------------------------------------------------------------------------

composite
   component
       property name="prop1" VALUE SUPPLIED HERE
       implementation.composite
           composite
               property mustSupply="true"  name="prop1"
               component

Regards

Simon