Re: [higgins-dev] Stored versus in-memory IProperty instances (was:IdAS

["Sergey Lyakhov" <slyakhov@xxxxxxxxxxxxxx>]

Jim,

> // Next, I assume all would agree that this would add the entire 
> myAttribute to mySubject2
> Vector v = new Vector();
> v.add(myAttribute);
> String s = myContext.addSubject("http://...#person";, "mySubject2", v, 
> null);

I think we should consider myAttribute as a parameter by value not by 
reference. For mySubject2 we should create its own attribute instance, not 
just set a reference to myAttribute. So there should not be any two 
DigitalSubjects which have a reference to the same attribute/value instance.

> // Next, I assume all would agree that this would add the entire 
> myAttribute to mySubject2
> Vector v = new Vector();
> v.add(myAttribute);
> String s = myContext.addSubject("http://...#person";, "mySubject2", v, 
> null);
> // Here's where I'm confused.  Does this affect mySubject1, mySubjet2, 
> both, or neither?
> myAttribute.setValue(buildSimpleValue("http://www.w3.org/2001/XMLSchema/normalizedString","brown";));

I think we should separate two possible situations:

1. Attribute is "in-memory" instance created by IContext.buildAttribute(). 
In this case IAttribute.setValue() shouldn't cause any changes for 
DigitalSubject. In other words setValue() for "in-memory" attribute should 
invoke only "in-memory" changes for this attribute.

2. Attibute was returned by IDigitalSubject.getAttribute(). In this case it 
is "stored" attribute and its value should be changed.

Thanks,
Sergey Lyakhov
----- Original Message ----- 
From: "Jim Sermersheim" <jimse@xxxxxxxxxx>
To: "'Higgins (Trust Framework) Project developer discussions'" 
<higgins-dev@xxxxxxxxxxx>
Sent: Wednesday, March 28, 2007 12:23 AM
Subject: [higgins-dev] Stored versus in-memory IProperty instances (was:IdAS 
is now Java 1.4)


> > > "Sergey Lyakhov" <slyakhov@xxxxxxxxxxxxxx> 3/27/07 10:51 AM >>>

<snip>

> 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.

I'm trying to envision what this would look like. Let's use some sample code 
to talk about it:

IDigitalSubject mySubject1 = myContext.getSubject("subject1");
IDigitalSubject mySubject2 = myContext.getSubject("subject2");
IAttribute myAttribute = mySubject1.getAttribute("eyeColor", null);

// At this point, is myAttribute associated with MySubject1 in terms of 
updates?
// In other words what happens here, does it only affect the in-memory copy, 
or does it also affect mySubject1?
// I think you're opinion is that this should affect mySubject1.
myAttribute.setValue(buildSimpleValue("http://www.w3.org/2001/XMLSchema/normalizedString","blue";));


// Next, I assume all would agree that this would add the entire myAttribute 
to mySubject2
Vector v = new Vector();
v.add(myAttribute);
String s = myContext.addSubject("http://...#person";, "mySubject2", v, null);

// Here's where I'm confused.  Does this affect mySubject1, mySubjet2, both, 
or neither?
myAttribute.setValue(buildSimpleValue("http://www.w3.org/2001/XMLSchema/normalizedString","brown";));

Jim

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