For my application, I want to model an HTML template in Neo4J, using the
MetaModel api.
So I started setting up MetaModelClasses for the various HTML entities.
e.g. (code in Scala)
val classProp = namespace.getMetaProperty("class", true)
val idProp =
namespace.getMetaProperty("id", true)
idProp.setCardinality(1)
val body = namespace.getMetaClass("body", true)
body.getDirectProperties(classProp)
body.getDirectProperties(idProp)
Which creates a class named "body" which has a property named "class" without a
cardinality restriction and a property named "id" with a cardinality
restriction of 1.
Now I can create nodes of class "body" with various values for "class" and for
"id".
So far so good, but now I want to say that the class body has a property
"tagname" which should get the value "body".
The meta model itself doesn't allow classes to have properties, but it allows
access to the underlying node of the class.
So I created a separate namespace for the meta meta classes and added the
following three definitions:
val tagName = metaNamespace.getMetaProperty("tagname", true)
tagName.setCardinality(1)
val taggable = metaNamespace.getMetaClass("taggable", true)
body.node.setProperty("tagname", "body")
This creates a property "tagname" with the value "body" for the class named
"body".
Now comes the more ambiguous part, how to link "body" to "taggable".
I can make body.node an instance of taggable. Once there is a validator, the
existence of a "tagname" property with cardinality 1 should be checked, so it
is reasonable to make body.node an instance of taggable.
At the same time the class body is actually a subclass of taggable, so I am
inclined to define that as well.
So I end up doing the following:
taggable.getDirectInstances.add(body.node)
taggable.getDirectSubs.add(body)
I would like to know if this is the correct approach to this situation, or
whether there are better alternatives.
Kind regards,
Niels Hoogeveen
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