| Re: [higgins-dev] IdAS is now Java 1.4 |
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Jim,
> - If the IdAS consumer got the IProperty instance from
IContext.buildAttribute, and then called setValue, we can assume it > sets
the value only on the in-memory IProperty instance (I think)
Yes, in my opinion, buildSimpleValue, buildComlexValue and
buildAttribute methods should always create only "in-memory"
objects.
> Let's assume there was a setValue method on IProperty. What are
the exact semantics of it?
> - If the IProperty instance was gotten by the IdAS consumer by calling
IDigitalSubject.getAttribute, would setValue cause > that value to be updated
on the underlying data at that point in time?
> - If the IdAS consumer got an IProperty instance from
IContext.buildAttribute, then used that IProperty instance to call
> IContext.addSubject, and after that called setValue on the IProperty
instance, does that update the value on the new
> subject in the context? Because IContext doesn't support transactions, I think this operation
(IProperty.setValue) should immediately update the value if Subject was
already "added" to the Context (in terms of previous IdAS model where
were two methods createSubject(...., boolean add) and
addSubject(IDigitalSubject subject)). If subject is not yet added to
the context it is "in-memory" object and all operations with such
Subject are also "in-memory".
As I understand, updateSubject(String cuid, Iterator
updates) method was added to IContext interface to provide
some data integrity support. However it doesn't work if we need to update
more then one Subject per one "transaction". In my opinion the
best decision was to add to IContext some methods like
commitChanges() and discardChanges(). So, objects like UpdateOperation
should be generated implicitly by calling methods like setValue(),
createSubject(), addAttribute() etc. if the context is based on some
technology which doesn't support transactions directly. > - If the IdAS consumer uses the same IProperty instance when creating
two Digital Subjects (via IContext.addSubject),
> and then calls setValue on that IProperty instance, does it update
both Digital Subjects?
> - If the IProperty instance was gotten by the IdAS consumer by calling
IDigitalSubject.getAttribute, and then used that
> IProperty instance to create a new Digital Subject, would setValue
update both Digital Subjects?
> If we allow IProperty instances to be used to update the Digital
Subjects to which they are associated, it means Context
> Providers will need to maintain associations between IProperty
instances and the Digital Subject(s) to which the IdAS
> consumer has associated them.
I think we need to create a new "stored" instance of IProperty for
each stored Digital Subject regardless of which type of IProperty ("stored" or
"in-memory") was passed to setValue(). In this case there will be no any two or
more Subjects which refers to the same "stored" instance of attribute,
metadata or value.
> Each Attribute in the data model is distinguished by it's Attribute
Type + Metadata combination.
> The IAttribute would actually have to be populated with it's type and
all the metadata in order to
> distinguish it from other attributes of the same type.
It is difficult to agree with it. We think that Attribute should not
be obliged to always have some (and unique) Metadata. Also we need to
analize metadata of all Attributes to define which Attribute
should be updated, that requires some time. From the other hand,
if we call setValue() method we know exactly which Attribute should be
updated.
In addition, to resolve problems with multiple
values (as simple as complex) of attribute I propose to add some
CollectionAttribute to IdAS model. So we will have exactly one value for
SimpleAttribute and for ComplexAttribute, and resolve a problem with
ComplexAttribute that now unable to have more than one complex value.
Thanks, Sergey Lyakhov
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