Your thoughts and finding makes a lot of sense and I too would be happy to
see those features in the meta model.
2010/4/11 Niels Hoogeveen <pd_aficion...@hotmail.com>
>
>
>
>
>
>
> I would be very happy when this functionally is implemented. Let's see who
> gets to this first. At the moment I am working on implementing meta model
> path expressions that can be used in a traverser, so it may take a couple of
> days for me to take a stab at building the instance restriction
> functionality.
>
> I do have another issue with the current implementation. I don't think it's
> a good idea to treat relationships and properties on the same footing. There
> may be common functionality, but that doesn't make a property the same as a
> relationship.
>
> I think it would be better to have interfaces PropertyRange and
> RelationshipRange, and having classes MetaModelProperty and
> MetaModelRelationship. Treating properties and relationships as equal,
> restricts the modelability of a Neo4J graph.
>
> As it stands, it is impossible to model the properties of a Relationship.
> Within the current design it is not possible to add that functionality,
> because it would mean the ability to set MetaModelProperties for
> MetaModelProperties. This would be correct for MetaModelProperties that
> denote relationships, but not for MetaModelProperties that denote
> properties.
>
> For my own project, I also run into problems that MetaModelProperty is not
> specific enough. I'd like to describe paths by means of their meta model
> entities. A path would take a form like this:
>
> MetaModelClass("some class name") --> RelationshipType("some relationship
> type name") --> MetaModelClass("some other class name") -->
> MetaModelProperty("some property name")
>
> There are two problems here. First of all, I need to use RelationshipType
> as a means to denote a relation. RelationshipType is not part of the meta
> model, and as a result has no cardinality information. Without unique names
> for PropertyTypes it is impossible to look up the MetaModelProperty a
> RelationshipType is related to, since there can be several
> MetaModelProperties with the same name. Even if such a lookup were possible,
> it is still a clumsy solution. It would be much nicer to be able to have a
> class MetaModelRelationship which denotes a relationship, and which has
> cardinality and range methods.
>
> Another issue is that I'd like to be able to state that the final element
> in a path is a property of some type. In the end, programs interact with
> users and other programs through values, not through objects. So most of the
> paths I would like to describe, will end with something that denotes a
> property value. Using MetaModelProperty for this purpose, doesn't work,
> because MetaModelProperty can denote both a property and a relationship.
>
> So I think we need three main types of ranges:
>
> InstanceRange
> ClassRanges
> PropertyRanges
>
> Each MetaModelRestrictable now takes a combination of the last two ranges,
> and, in my opinion, those should be separated:
>
> MetaModelProperty (takes PropertyRange and has cardinality methods)
> MetaModelRelationship (takes ClassRange or InstanceRange* and has
> cardinality methods)
> MetaModelClass (takes InstanceRange and has cardinality methods)
>
> *An InstanceRange on MetaModelRelationship means that each instance of a
> class can only have a particular relationship with certain instances. A
> class range on MetaModelRelationship means that each instance of a class can
> only have a particular relationship with instances of a certain classes.
>
>
> MetaModelClass will additionally have:
>
> getAllInstances()
> getDirectInstances()
> getAllPropertyTypes()
> getDirectPropertyTypes()
> getAllRelationshipsTypes()
> getDirectRelationshipsTypes()
> getPropertyRestriction(MetaModelProperty, boolean) returns
> MetaModelPropertyRestriction
> getRelationshipRestriction(MetaModelRelationship, boolean) returns
> MetaModelRelationshipRestriction
>
> MetaModelRelationship will additionally have:
>
> getAllPropertyTypes()
>
> getDirectPropertyTypes()
> getPropertyRestriction(MetaModelProperty, boolean) returns
> MetaModelPropertyRestriction
>
>
> MetaModelProperty needs no additional methods not already covered in the
> current implementation.
>
> Kind regards,
> Niels Hoogeveen
>
> P.S. I think it should be smart to introduce one more entity
> MetaModelMetaClass, which I will write about later.
>
>
>
> > Date: Fri, 9 Apr 2010 13:36:12 +0200
> > From: matt...@neotechnology.com
> > To: user@lists.neo4j.org
> > Subject: Re: [Neo] meta meta classes
> >
> > Now we're getting somewhere... I like this solution a lot, thanks for the
> > great idea. Let me see if I get time to try and implement it soon! Or if
> you
> > get to if before me and supply a patch. It's nice either way :)
> >
> > 2010/4/9 Niels Hoogeveen <pd_aficion...@hotmail.com>
> >
> > >
> > > Having thought about implementation a little bit more, it would be neat
> to
> > > have MetaModelClass implement an interface similar to
> MetaModelRestrictable,
> > > with one difference, the setRange and getRange don't refer to a
> > > PropertyRange but to an InstanceRange.
> > >
> > > Like PropertyRange, InstanceRange should be an abstract class so
> several
> > > different different implementations of InstanceRanges can be provided:
> > >
> > > * InstanceEnumerationRange (enumerates the n instances the class
> contains
> > > and sets minCardinality = maxCardinality = n )
> > > * IndexedInstanceRange (indexes the n instances it contains and sets
> > > minCardinality = maxCardinality = n, making the class into an Instance
> > > array)
> > > * NullInstanceRange (set minCardinality = maxCardinality = 0, making
> the
> > > class abstract)
> > > * InstanceClassesRange (states that the instances of a class have to be
> > > instances of one of a given set of classes)
> > >
> > > The first three range types restrict the MetaModelClass to having no
> > > getDirectInstances.add functionality, and also the setting of
> cardinality
> > > should be disabled, which makes me wonder if we need a class
> > > FixedMetaModelClass, which simply doesn't provide these methods, or if
> we
> > > should throw exceptions when methods are inappropriately called, or if
> we
> > > allow inconsistent data like the rest of the meta model does.
> > >
> > >
> > > > From: pd_aficion...@hotmail.com
> > > > To: user@lists.neo4j.org
> > > > Date: Thu, 8 Apr 2010 23:52:02 +0200
> > > > Subject: Re: [Neo] meta meta classes
> > > >
> > > >
> > > > I think the best solution here is to have an instance enumeration on
> > > MetaModelClass. Singletons are special case of an enumeration.
> > > >
> > > > See:
> > > > http://www.w3.org/TR/2002/WD-owl-ref-20021112/#Enumerated
> > > >
> > >
> http://owl.cs.manchester.ac.uk/2007/05/api/javadoc/org/semanticweb/owl/model/OWLObjectOneOf.html
> > > >
> > > >
> > > >
> > > > > Date: Thu, 8 Apr 2010 22:33:11 +0200
> > > > > From: matt...@neotechnology.com
> > > > > To: user@lists.neo4j.org
> > > > > Subject: Re: [Neo] meta meta classes
> > > > >
> > > > > Ok now I get your point! Thank you for clarifying.
> > > > >
> > > > > Your singleton proposal could be a good idea then. Could it
> > > > > potentially be a hindrance in some scenario? I mean should we have
> a
> > > > > MetaModelClass#setSingleton(boolean) or something so that this
> > > > > behaviour can be controlled?
> > > > >
> > > > > 2010/4/8, Niels Hoogeveen <pd_aficion...@hotmail.com>:
> > > > > >
> > > > > > Each country needs to be modeled as classes, because I want to
> set
> > > the
> > > > > > restriction that French regions (which can have different
> properties
> > > from
> > > > > > Canadian provinces) can only have a relationship with the country
> > > France,
> > > > > > and Canadian provinces can only have a relationship with the
> country
> > > Canada.
> > > > > > The domain and the range of a PropertyType are classes not
> instances.
> > > If
> > > > > > countries were simply instances of the "country" class, it would
> be
> > > > > > possible to say that an instance of a Canadian province is a
> > > subdivision of
> > > > > > France.
> > > > > >
> > > > > > I'd like to be able to iterate over the subdivision of France and
> > > have
> > > > > > guaranteed that each instance has the property "region code", a
> > > property
> > > > > > unknown to Canadian provinces. Without having a restriction
> stating
> > > that a
> > > > > > specific sub-division belongs to a specific country, any
> sub-division
> > > can be
> > > > > > related to any country, so a user may erroneously say that
> Alberta is
> > > a
> > > > > > French region. Not only is this factually incorrect, but
> structurally
> > > too.
> > > > > > Alberta, being a Canadian province, doesn't have the "region
> code"
> > > property,
> > > > > > which I want French regions to have.
> > > > > >
> > > > > >
> > > > > >> Date: Thu, 8 Apr 2010 20:06:32 +0200
> > > > > >> From: matt...@neotechnology.com
> > > > > >> To: user@lists.neo4j.org
> > > > > >> Subject: Re: [Neo] meta meta classes
> > > > > >>
> > > > > >> 2010/4/8 Niels Hoogeveen <pd_aficion...@hotmail.com>
> > > > > >>
> > > > > >> >
> > > > > >> > Your point about the cardinality restriction is a correct
> > > observation.
> > > > > >> >
> > > > > >> > In fact it would be better to create a "is-subdivision-of"
> > > PropertyType
> > > > > >> > on
> > > > > >> > "sub-division" and give that a range "country" with a
> cardinality
> > > of 1.
> > > > > >> > Then
> > > > > >> > for each subclass of "sub-division" a restriction should be
> set,
> > > naming
> > > > > >> > the
> > > > > >> > "country" class this specific "sub-division" class applies to.
> > > > > >> >
> > > > > >> > Still, it requires each country to be defined as both a class
> and
> > > an
> > > > > >> > instance.
> > > > > >> >
> > > > > >> Why just countries as classes? why not each subdivision as
> classes
> > > as
> > > > > >> well?
> > > > > >> Why countries as classes at all?
> > > > > >>
> > > > > >> >
> > > > > >> > > Date: Thu, 8 Apr 2010 19:15:30 +0200
> > > > > >> > > From: matt...@neotechnology.com
> > > > > >> > > To: user@lists.neo4j.org
> > > > > >> > > Subject: Re: [Neo] meta meta classes
> > > > > >> > >
> > > > > >> > > So, you describe the model (with "country", "sub-division"
> and
> > > > > >> > > "has-sub-division") which is OK! Then you not just want to
> add
> > > data
> > > > > >> > > which
> > > > > >> > > would conform to it, you also describe the highest level of
> that
> > > data
> > > > > >> > > in
> > > > > >> > the
> > > > > >> > > meta model itself with cardinality for how many
> sub-divisions
> > > each
> > > > > >> > > such
> > > > > >> > > level must contain.
> > > > > >> > >
> > > > > >> > > My first though here is: why put actual data into the meta
> model
> > > (the
> > > > > >> > design
> > > > > >> > > isn't intended for that)?
> > > > > >> > > The second is: why (since you put actual data into the meta
> > > model)
> > > > > >> > > would
> > > > > >> > you
> > > > > >> > > stop there? why only say that "France" have 10 subdivisions?
> You
> > > don't
> > > > > >> > say
> > > > > >> > > exactly which subdivisions or how many/which subdivisions
> each
> > > > > >> > subdivision
> > > > > >> > > has, a.s.o. Which benefits would modeling only the highest
> level
> > > of
> > > > > >> > > data
> > > > > >> > get
> > > > > >> > > you? And if you could describe the entire data in the meta
> > > model, you
> > > > > >> > > end
> > > > > >> > up
> > > > > >> > > with a meta model which describes the entire data and then,
> in
> > > > > >> > > addition,
> > > > > >> > the
> > > > > >> > > data which is exactly the same as the meta model... what
> > > benefits does
> > > > > >> > that
> > > > > >> > > give you?
> > > > > >> > >
> > > > > >> > > I'm just confused about the fact that you want to have the
> meta
> > > model
> > > > > >> > > (classes, properties, restrictions) and (some of) the actual
> > > data
> > > > > >> > > modeled
> > > > > >> > in
> > > > > >> > > the meta model, whereas the meta model was intended to model
> the
> > > meta
> > > > > >> > model
> > > > > >> > > (the UML diagram, so to speak) and not the actual data it
> would
> > > have
> > > > > >> > conform
> > > > > >> > > to it.
> > > > > >> > >
> > > > > >> > > Help me understand which benefits you're after by modeling
> the
> > > "top
> > > > > >> > level"
> > > > > >> > > of your actual data into the meta model itself.
> > > > > >> > >
> > > > > >> > >
> > > > > >> > > Best,
> > > > > >> > > Mattias
> > > > > >> > >
> > > > > >> > > 2010/4/8 Niels Hoogeveen <pd_aficion...@hotmail.com>
> > > > > >> > >
> > > > > >> > > >
> > > > > >> > > > The example of the tag library and countries/sub-divisions
> are
> > > not
> > > > > >> > > > necessarily similar. The first shows the need to model the
> > > > > >> > > > properties
> > > > > >> > of a
> > > > > >> > > > class.
> > > > > >> > > >
> > > > > >> > > > The second example shows the need to have singleton
> classes,
> > > which
> > > > > >> > > > is a
> > > > > >> > > > different concept, and something that cannot be done out
> of
> > > the box,
> > > > > >> > but I
> > > > > >> > > > will show a solution that requires minimal modifications
> to
> > > the
> > > > > >> > > > current
> > > > > >> > > > software.
> > > > > >> > > >
> > > > > >> > > > Suppose we want to model "countries" and their
> > > "sub-divisions".
> > > > > >> > > >
> > > > > >> > > > We do the following:
> > > > > >> > > >
> > > > > >> > > > create class "country"
> > > > > >> > > > create class "sub-division"
> > > > > >> > > > create property "has-sub-division"
> > > > > >> > > > make "has-subdivision" a property of "country"
> > > > > >> > > >
> > > > > >> > > > Now we like to populate the database, since all countries
> have
> > > > > >> > different
> > > > > >> > > > types of sub-divisions we need to create those:
> > > > > >> > > >
> > > > > >> > > > create class "french_region"
> > > > > >> > > > create class "canadian_province"
> > > > > >> > > > create class "canadian_territory"
> > > > > >> > > > create class "US_state"
> > > > > >> > > > etc.
> > > > > >> > > >
> > > > > >> > > > Populate the various classes with instances:
> > > > > >> > > >
> > > > > >> > > > create node for "Alsace" and make it an instance of
> > > "french_region"
> > > > > >> > > > create node for "Aquitaine" and make it an instance of
> > > > > >> > > > "french_region"
> > > > > >> > > > create node for "Alberta" and make it an instance of
> > > > > >> > > > "Canadian_province"
> > > > > >> > > > create node for "Nanavut" and make it an instance of
> > > > > >> > > > "Canadian_territory"
> > > > > >> > > > create node for "British Columbia" and make it an instance
> of
> > > > > >> > > > "Canadian_province"
> > > > > >> > > > create node for "Alabama" and make it an instance of
> > > > > >> > > > "US_State"
> > > > > >> > > > create node for "Alaska" and make it an instance of
> > > > > >> > > > "US_State"
> > > > > >> > > > etc.
> > > > > >> > > >
> > > > > >> > > > We'd like to state that each country has its own
> restriction
> > > on the
> > > > > >> > type of
> > > > > >> > > > subdivision. To do that we need to create classes for each
> > > country.
> > > > > >> > > >
> > > > > >> > > > create class "France"
> > > > > >> > > > create class "Canada"
> > > > > >> > > > create class "United_States_of_America"
> > > > > >> > > > etc.
> > > > > >> > > >
> > > > > >> > > > make class "France" a subclass of "Country"
> > > > > >> > > > make class "Canada" a subclass of "Country"
> > > > > >> > > > make class "United_States_of_America" a subclass of
> "Country"
> > > > > >> > > > etc.
> > > > > >> > > >
> > > > > >> > > > create restriction for "France" on "has-sub-division" with
> > > range
> > > > > >> > > > "french_province" and cardinality = 26
> > > > > >> > > > create restriction for "Canada" on "has-sub-division" with
> > > range
> > > > > >> > > > "canadian_province" and cardinality = 10
> > > > > >> > > > create restriction for "Canada" on "has-sub-division" with
> > > range
> > > > > >> > > > "canadian_territory" and cardinality = 3
> > > > > >> > > > create restriction for "United_States_of_America" on
> > > > > >> > > > "has-sub-division"
> > > > > >> > > > with range "US_State" and cardinality = 50
> > > > > >> > > > etc.
> > > > > >> > > >
> > > > > >> > > > Now we have classes for each country, but no instances.
> > > > > >> > > > Unfortunately
> > > > > >> > we
> > > > > >> > > > cannot say that a class is an instance of itself, that
> would
> > > require
> > > > > >> > > > a
> > > > > >> > > > relationsship where the endnode equals the startnode,
> which
> > > Neo4J
> > > > > >> > doesn't
> > > > > >> > > > allow. So we have to create separate instances for each
> > > country.
> > > > > >> > > >
> > > > > >> > > > create node for "France"
> > > > > >> > > > create node for "Canada"
> > > > > >> > > > create node for "United_States_Of_America"
> > > > > >> > > > etc.
> > > > > >> > > >
> > > > > >> > > > make node "France" an instance of class "France"
> > > > > >> > > > make node "Canada" an instance of class "Canada"
> > > > > >> > > > make node "United_States_of_America" an instance of class
> > > > > >> > > > "United_States_of_America"
> > > > > >> > > >
> > > > > >> > > > And finally link the subdivisions to their countries:
> > > > > >> > > >
> > > > > >> > > > "France" "has-sub-division" "Alsace"
> > > > > >> > > > "France" "has-sub-division" "Aquitaine"
> > > > > >> > > > "Canada" "has-sub-division-of" "Alberta"
> > > > > >> > > > "Canada" "has-subdivision" "British Columbia"
> > > > > >> > > > "Canada" "has-subdivision" "Nanavut"
> > > > > >> > > > "United_States_of_America" "has-sub-division" "Alabama"
> > > > > >> > > > "United_States_of_America" "has-sub-division" "Alaska"
> > > > > >> > > >
> > > > > >> > > > So we end up having a class for each country and an
> instance
> > > for
> > > > > >> > > > each
> > > > > >> > > > country.
> > > > > >> > > >
> > > > > >> > > > Writing this down, I realize the patch I sent you a few
> days
> > > ago,
> > > > > >> > contains
> > > > > >> > > > a minor flaw, that needs to be fixed. In that patch I
> added an
> > > > > >> > > > indexed
> > > > > >> > > > property "uri" to the meta model, to bring it in line with
> > > what is
> > > > > >> > being
> > > > > >> > > > done in the RDF module, and to make certain that the same
> URI
> > > is not
> > > > > >> > used
> > > > > >> > > > for two different properties. Without unicity a class can
> have
> > > > > >> > > > several
> > > > > >> > > > different ProperyTypes with the same name. In that
> situation
> > > the
> > > > > >> > > > lookup
> > > > > >> > of
> > > > > >> > > > the PropertyType of a property or relationship becomes
> > > impossible.
> > > > > >> > > >
> > > > > >> > > > The flaw in my patch is the name of the "uri" property,
> which
> > > should
> > > > > >> > > > be
> > > > > >> > > > something like "class_uri". That way the class of each
> country
> > > can
> > > > > >> > > > be
> > > > > >> > given
> > > > > >> > > > the same URI as the instance of each country, because they
> > > live in
> > > > > >> > different
> > > > > >> > > > name spaces.
> > > > > >> > > >
> > > > > >> > > > This same technique is used in OWL to provide "punning".
> An
> > > instance
> > > > > >> > and a
> > > > > >> > > > class can have the same URI, because instances in OWL live
> in
> > > a
> > > > > >> > different
> > > > > >> > > > namespaces from classes.
> > > > > >> > > >
> > > > > >> > > > Through the use of the "uri" property and the "class_uri"
> > > property
> > > > > >> > > > we
> > > > > >> > can
> > > > > >> > > > also distill that each country class is a singleton class,
> > > because
> > > > > >> > there
> > > > > >> > > > exists an instance with the same URI. That way we can work
> > > around
> > > > > >> > > > the
> > > > > >> > > > limitation that relationships cannot have the same start
> and
> > > end
> > > > > >> > > > node.
> > > > > >> > > >
> > > > > >> > > > Furthermore, it allows for some extra restrictions to
> > > MetaModelClass
> > > > > >> > with
> > > > > >> > > > the following logic: If a class has exactly one instance
> where
> > > the
> > > > > >> > "uri" of
> > > > > >> > > > that instance equals the "class_uri" of the class, no more
> > > instances
> > > > > >> > can be
> > > > > >> > > > added And if there is an instance of a class without a
> "uri"
> > > that
> > > > > >> > equals the
> > > > > >> > > > "class_uri", no instances can be added where the "uri" of
> the
> > > > > >> > > > instance
> > > > > >> > > > equals the "class_uri" of the class. With that logic, we
> have
> > > proper
> > > > > >> > > > singleton classes in the meta model of Neo4J.
> > > > > >> > > >
> > > > > >> > > > Kind regards,
> > > > > >> > > > Niels Hoogeveen
> > > > > >> > > >
> > > > > >> > > > > Date: Thu, 8 Apr 2010 11:37:37 +0200
> > > > > >> > > > > From: matt...@neotechnology.com
> > > > > >> > > > > To: user@lists.neo4j.org
> > > > > >> > > > > Subject: Re: [Neo] meta meta classes
> > > > > >> > > > >
> > > > > >> > > > > 2010/3/30 Niels Hoogeveen <pd_aficion...@hotmail.com>
> > > > > >> > > > >
> > > > > >> > > > > >
> > > > > >> > > > > > MetaModelObject already has a getter (without using
> the
> > > word
> > > > > >> > > > > > "get")
> > > > > >> > to
> > > > > >> > > > > > access the node.
> > > > > >> > > > > >
> > > > > >> > > > > > Wrapping MetaModelObject to give it a Node-interface
> makes
> > > it
> > > > > >> > possible
> > > > > >> > > > to
> > > > > >> > > > > > directly write:
> > > > > >> > > > > >
> > > > > >> > > > > > metalObject.setProperty("a", b)
> > > > > >> > > > > >
> > > > > >> > > > > > instead of
> > > > > >> > > > > >
> > > > > >> > > > > > metaobject.node.setPropert("a", b)
> > > > > >> > > > > >
> > > > > >> > > > > > If that were all, I wouldn't make a post about it. The
> > > more
> > > > > >> > interesting
> > > > > >> > > > > > part is the meta modeling of the node gotten from a
> > > > > >> > MetaModelObject.
> > > > > >> > > > This
> > > > > >> > > > > > node represents the class, but it is not an instance
> of
> > > any
> > > > > >> > > > > > class
> > > > > >> > > > itself.
> > > > > >> > > > > > That's where the reify method comes into play, which
> takes
> > > the
> > > > > >> > > > > > node
> > > > > >> > > > from a
> > > > > >> > > > > > MetaModelObject and creates a class with the same
> name,
> > > but in a
> > > > > >> > > > different
> > > > > >> > > > > > namespace, and makes the node an instance of this new
> > > class.
> > > > > >> > > > > >
> > > > > >> > > > > > With that construction it becomes possible to model
> the
> > > > > >> > > > > > relationships/properties of a class.
> > > > > >> > > > > >
> > > > > >> > > > > > There are many examples where this can be handy.
> > > > > >> > > > > >
> > > > > >> > > > > > I already gave the example of HTML tags, where the
> > > attributes
> > > > > >> > > > > > can
> > > > > >> > be
> > > > > >> > > > > > modeled as properties and the tagname as a property of
> the
> > > meta
> > > > > >> > class.
> > > > > >> > > > > >
> > > > > >> > > > > > Another example is:
> > > > > >> > > > > >
> > > > > >> > > > > > All countries have subdivision. Countries and their
> > > subdivisions
> > > > > >> > all
> > > > > >> > > > are
> > > > > >> > > > > > instances of a certain class. There is one class for
> > > country,
> > > > > >> > > > > > but
> > > > > >> > there
> > > > > >> > > > is a
> > > > > >> > > > > > set of classes for subdivisions. In some countries, a
> > > > > >> > > > > > subdivision
> > > > > >> > is
> > > > > >> > > > called
> > > > > >> > > > > > "province", in others it's a "state" or a "district".
> > > > > >> > > > > > Subdivision
> > > > > >> > of
> > > > > >> > > > various
> > > > > >> > > > > > countries can have different sets of properties and
> > > relations.
> > > > > >> > > > > >
> > > > > >> > > > > > How to model the fact that the instance "United States
> of
> > > > > >> > > > > > America"
> > > > > >> > has
> > > > > >> > > > > > subdivisions of the class "State_(US)"? Using the
> reify
> > > method
> > > > > >> > > > > > we
> > > > > >> > can
> > > > > >> > > > make a
> > > > > >> > > > > > class "United States of America", where we can model
> that
> > > the
> > > > > >> > > > ClassRange of
> > > > > >> > > > > > "State_(US)" is "United States of America". Or if we
> want
> > > the
> > > > > >> > > > relationship
> > > > > >> > > > > > to point the other way, that the "United States of
> > > America" has
> > > > > >> > > > > > 50
> > > > > >> > (use
> > > > > >> > > > of
> > > > > >> > > > > > cardinality) subdivisions of the class "State_(US)".
> > > > > >> > > > > >
> > > > > >> > > > > Here you take a step into modeling the actual data into
> the
> > > meta
> > > > > >> > model
> > > > > >> > > > which
> > > > > >> > > > > describes the data. Is it desirable to first model
> exactly
> > > how the
> > > > > >> > data
> > > > > >> > > > will
> > > > > >> > > > > look, and then add data so that it looks like that? I
> get a
> > > > > >> > > > > feeling
> > > > > >> > that
> > > > > >> > > > the
> > > > > >> > > > > data is described twice here...
> > > > > >> > > > >
> > > > > >> > > > > >
> > > > > >> > > > > > Of course all this can directly be expressed with
> nodes
> > > and
> > > > > >> > > > relationships,
> > > > > >> > > > > > but that's what the meta model does anyway.
> > > > > >> > > > > >
> > > > > >> > > > > > I do have one peeve with the meta model API. The class
> > > DataRange
> > > > > >> > has a
> > > > > >> > > > > > constructor:
> > > > > >> > > > > >
> > > > > >> > > > > > DataRange(String datatype, Object... values)
> > > > > >> > > > > >
> > > > > >> > > > > > I'd much rather see a new Restrictable class
> Datavalue,
> > > and see
> > > > > >> > > > > > a
> > > > > >> > > > > > constructor:
> > > > > >> > > > > >
> > > > > >> > > > > > DataRange(String datatype, Datavalue... values)
> > > > > >> > > > > >
> > > > > >> > > > > > That way the possible values a property can have
> > > additional
> > > > > >> > properties
> > > > > >> > > > and
> > > > > >> > > > > > relationships (eg. link to Wordnet definition or
> Wikipedia
> > > > > >> > > > > > entry).
> > > > > >> > > > > >
> > > > > >> > > > > > Kind regards,
> > > > > >> > > > > > Niels Hoogeveen
> > > > > >> > > > > >
> > > > > >> > > > > >
> > > > > >> > > > > >
> > > > > >> > > > > >
> > > > > >> > > > > >
> > > > > >> > > > > >
> > > > > >> > > > > > > Date: Tue, 30 Mar 2010 09:30:10 +0200
> > > > > >> > > > > > > From: matt...@neotechnology.com
> > > > > >> > > > > > > To: user@lists.neo4j.org
> > > > > >> > > > > > > Subject: Re: [Neo] meta meta classes
> > > > > >> > > > > > >
> > > > > >> > > > > > > Would making the underlying Node publically
> available
> > > (via a
> > > > > >> > getter)
> > > > > >> > > > be
> > > > > >> > > > > > > virtually the same thing? In that case the meta
> model
> > > classes
> > > > > >> > could
> > > > > >> > > > have
> > > > > >> > > > > > > such a getter.
> > > > > >> > > > > > >
> > > > > >> > > > > > > 2010/3/26 Niels Hoogeveen <
> pd_aficion...@hotmail.com>
> > > > > >> > > > > > >
> > > > > >> > > > > > > >
> > > > > >> > > > > > > > Hi Peter,
> > > > > >> > > > > > > >
> > > > > >> > > > > > > > I added a Wiki entry in my github repo called
> > > "Reification
> > > > > >> > > > > > > > of
> > > > > >> > meta
> > > > > >> > > > > > classes
> > > > > >> > > > > > > > and meta properties":
> > > > > >> > > > > > > >
> > > > > >> > > > > > > >
> > > > > >> > > > > > > >
> > > > > >> > > > > >
> > > > > >> > > >
> > > > > >> >
> > >
> http://wiki.github.com/NielsHoogeveen/Scala-Neo4j-utils/reification-of-meta-classes-and-meta-properties
> > > > > >> > > > > > > >
> > > > > >> > > > > > > > The source code for the Scala wrappers can be
> found
> > > found in
> > > > > >> > > > > > > > my
> > > > > >> > > > repo:
> > > > > >> > > > > > > >
> > > > > >> > > > > > > >
> http://github.com/NielsHoogeveen/Scala-Neo4j-utils
> > > > > >> > > > > > > >
> > > > > >> > > > > > > > Kind regards,
> > > > > >> > > > > > > > Niels Hoogeveen
> > > > > >> > > > > > > >
> > > > > >> > > > > > > > > From: neubauer.pe...@gmail.com
> > > > > >> > > > > > > > > Date: Fri, 26 Mar 2010 17:25:01 +0100
> > > > > >> > > > > > > > > To: user@lists.neo4j.org
> > > > > >> > > > > > > > > Subject: Re: [Neo] meta meta classes
> > > > > >> > > > > > > > >
> > > > > >> > > > > > > > > Awesome Niels!
> > > > > >> > > > > > > > >
> > > > > >> > > > > > > > > maybe you could blog or document some cool
> example
> > > on
> > > > > >> > > > > > > > > this?
> > > > > >> > > > > > > > >
> > > > > >> > > > > > > > > Cheers,
> > > > > >> > > > > > > > >
> > > > > >> > > > > > > > > /peter neubauer
> > > > > >> > > > > > > > >
> > > > > >> > > > > > > > > COO and Sales, Neo Technology
> > > > > >> > > > > > > > >
> > > > > >> > > > > > > > > GTalk: neubauer.peter
> > > > > >> > > > > > > > > Skype peter.neubauer
> > > > > >> > > > > > > > > Phone +46 704 106975
> > > > > >> > > > > > > > > LinkedIn http://www.linkedin.com/in/neubauer
> > > > > >> > > > > > > > > Twitter http://twitter.com/peterneubauer
> > > > > >> > > > > > > > >
> > > > > >> > > > > > > > > http://www.neo4j.org - Your high
> > > performance
> > > > > >> > graph
> > > > > >> > > > > > database.
> > > > > >> > > > > > > > > http://www.tinkerpop.com - Processing for
> > > > > >> > Internet-scale
> > > > > >> > > > > > graphs.
> > > > > >> > > > > > > > > http://www.thoughtmade.com - Scandinavias
> coolest
> > > > > >> > Bring-a-Thing
> > > > > >> > > > > > party.
> > > > > >> > > > > > > > >
> > > > > >> > > > > > > > >
> > > > > >> > > > > > > > >
> > > > > >> > > > > > > > > On Fri, Mar 26, 2010 at 5:22 PM, Niels Hoogeveen
> > > > > >> > > > > > > > > <pd_aficion...@hotmail.com> wrote:
> > > > > >> > > > > > > > > >
> > > > > >> > > > > > > > > > Using Scala, I was actually able to extend
> > > > > >> > > > > > > > > > MetaModelThing
> > > > > >> > to
> > > > > >> > > > act as
> > > > > >> > > > > > a
> > > > > >> > > > > > > > Node and MetaModelClass to have shadowing
> > > functionality for
> > > > > >> > both
> > > > > >> > > > > > > > MetaModelClasses and for MetaModelProperties,
> without
> > > > > >> > > > > > > > touching
> > > > > >> > the
> > > > > >> > > > > > original
> > > > > >> > > > > > > > source code.
> > > > > >> > > > > > > > > >
> > > > > >> > > > > > > > > >> To: user@lists.neo4j.org
> > > > > >> > > > > > > > > >> From: rick.bullo...@burningskysoftware.com
> > > > > >> > > > > > > > > >> Date: Fri, 26 Mar 2010 14:29:03 +0000
> > > > > >> > > > > > > > > >> Subject: Re: [Neo] meta meta classes
> > > > > >> > > > > > > > > >>
> > > > > >> > > > > > > > > >> Such are the joys and challenges of
> frameworks
> > > and
> > > > > >> > > > abstractions.
> > > > > >> > > > > > > > Sometimes you do need to get "close to the metal"
> > > though,
> > > > > >> > > > > > > > to
> > > > > >> > > > achieve
> > > > > >> > > > > > > > specific functional and performance requirements.
> > > Thus the
> > > > > >> > reason
> > > > > >> > > > open
> > > > > >> > > > > > > > source frameworks are awesome. At least we can
> change
> > > and
> > > > > >> > extend
> > > > > >> > > > them
> > > > > >> > > > > > more
> > > > > >> > > > > > > > easily!
> > > > > >> > > > > > > > > >>
> > > > > >> > > > > > > > > >>
> > > > > >> > > > > > > > > >>
> > > > > >> > > > > > > > > >> -----Original Message-----
> > > > > >> > > > > > > > > >> From: Niels Hoogeveen <
> pd_aficion...@hotmail.com
> > > >
> > > > > >> > > > > > > > > >> Date: Fri, 26 Mar 2010 15:20:15
> > > > > >> > > > > > > > > >> To: <user@lists.neo4j.org>
> > > > > >> > > > > > > > > >> Subject: Re: [Neo] meta meta classes
> > > > > >> > > > > > > > > >>
> > > > > >> > > > > > > > > >>
> > > > > >> > > > > > > > > >> Making MetaModelThing implement the Node
> > > interface is
> > > > > >> > actually
> > > > > >> > > > > > > > orthogonal to the creation of Shadow objects.
> Though
> > > it does
> > > > > >> > make
> > > > > >> > > > code
> > > > > >> > > > > > using
> > > > > >> > > > > > > > classes as objects cleaner, and allows the node
> > > property of
> > > > > >> > > > > > MetaModelThing
> > > > > >> > > > > > > > to become private.
> > > > > >> > > > > > > > > >>
> > > > > >> > > > > > > > > >> > From: pd_aficion...@hotmail.com
> > > > > >> > > > > > > > > >> > To: user@lists.neo4j.org
> > > > > >> > > > > > > > > >> > Date: Fri, 26 Mar 2010 14:38:08 +0100
> > > > > >> > > > > > > > > >> > Subject: Re: [Neo] meta meta classes
> > > > > >> > > > > > > > > >> >
> > > > > >> > > > > > > > > >> >
> > > > > >> > > > > > > > > >> > Or, and this probably the simplest
> solution.
> > > Let a
> > > > > >> > > > > > MetaModelThing
> > > > > >> > > > > > > > implement the Node interface. This allows a class
> to
> > > be an
> > > > > >> > instance
> > > > > >> > > > of
> > > > > >> > > > > > > > another class and/or a SubType of another class.
> > > > > >> > > > > > > > > >> >
> > > > > >> > > > > > > > > >> >
> > > > > >> > > > > > > > > >> > > From: pd_aficion...@hotmail.com
> > > > > >> > > > > > > > > >> > > To: user@lists.neo4j.org
> > > > > >> > > > > > > > > >> > > Date: Fri, 26 Mar 2010 14:20:07 +0100
> > > > > >> > > > > > > > > >> > > Subject: Re: [Neo] meta meta classes
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > > > > > >> > > The class as object phenomenon is
> actually
> > > quite
> > > > > >> > > > pervasive,
> > > > > >> > > > > > and I
> > > > > >> > > > > > > > think it is possible to have a generalized
> solution
> > > for it.
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > > > > > >> > > After sending this email yesterday, I
> came up
> > > with
> > > > > >> > > > > > > > > >> > > a
> > > > > >> > > > slightly
> > > > > >> > > > > > > > different solution.
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > > > > > >> > > val taggable =
> > > namespace.getMetaClass("taggable",
> > > > > >> > true)
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > > > > > >> > > val tagName =
> > > > > >> > > > metaModelNamespace.getMetaProperty("tagname",
> > > > > >> > > > > > true)
> > > > > >> > > > > > > > > >> > > tagName.setCardinality(1)
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > > > > > >> > > val metaTaggable =
> > > > > >> > > > metaModelNamespace.getMetaClass("taggable",
> > > > > >> > > > > > > > true)
> > > > > >> > > > > > > > > >> > >
> metaTaggable.getDirectProperties.add(tagName)
> > > > > >> > > > > > > > > >> > >
> > > metaTaggable.getDirectInstances.add(taggable.node)
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > > > > > >> > > val body = namespace.getMetaClass("body",
> > > true)
> > > > > >> > > > > > > > > >> > > taggable.getDirectSubs.add(body)
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > > > > > >> > > Instead of directly relating the class
> "body"
> > > to
> > > > > >> > > > > > > > > >> > > the
> > > > > >> > meta
> > > > > >> > > > > > class
> > > > > >> > > > > > > > "taggable", I create a shadow of the meta class
> > > "taggable"
> > > > > >> > > > > > > > with
> > > > > >> > the
> > > > > >> > > > > > same
> > > > > >> > > > > > > > name in the namespace of the class "body", and
> make
> > > "body" a
> > > > > >> > > > subclass
> > > > > >> > > > > > of
> > > > > >> > > > > > > > this shadow. That way the sub classing
> relationship
> > > remains
> > > > > >> > nicely
> > > > > >> > > > in
> > > > > >> > > > > > one
> > > > > >> > > > > > > > name space, while the instance relationship
> transcends
> > > name
> > > > > >> > spaces,
> > > > > >> > > > as
> > > > > >> > > > > > it
> > > > > >> > > > > > > > should.
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > > > > > >> > > This could in principle be generalized by
> > > adding a
> > > > > >> > methods
> > > > > >> > > > to
> > > > > >> > > > > > > > MetaModelClass:
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > > > > > >> > > public MetaModelClass
> > > createShadowClass(NameSpace
> > > > > >> > > > > > > > > >> > > ns){
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > > > > > >> > > MetaModelClass mc =
> > > > > >> > ns.getMetaClass(this.getName(),
> > > > > >> > > > true);
> > > > > >> > > > > > > > > >> > > this.getDirectInstances.add(mc.node);
> > > > > >> > > > > > > > > >> > > return mc;
> > > > > >> > > > > > > > > >> > > }
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > > > > > >> > > This returns a shadow of a given
> > > MetaModelClass in
> > > > > >> > > > > > > > > >> > > a
> > > > > >> > given
> > > > > >> > > > > > > > namespace and adds it as a an instance of this.
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > > > > > >> > > It would of course be nicer to have a
> method
> > > with
> > > > > >> > > > > > > > > >> > > the
> > > > > >> > > > > > signature:
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > > > > > >> > > public MetaModelClass getShadow(NameSpace
> ns,
> > > > > >> > > > > > > > > >> > > Boolean
> > > > > >> > > > create)
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > > > > > >> > > This is much more in line with the rest
> of
> > > the API,
> > > > > >> > but
> > > > > >> > > > > > requires a
> > > > > >> > > > > > > > way to find out the namespace a given
> MetaModelClass
> > > is
> > > > > >> > > > > > > > defined
> > > > > >> > in.
> > > > > >> > > > I
> > > > > >> > > > > > didn't
> > > > > >> > > > > > > > see a method getNamespace() for a given class, and
> > > didn't
> > > > > >> > > > > > > > delve
> > > > > >> > > > deeply
> > > > > >> > > > > > > > enough in the source code to figure out how to do
> > > that.
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > > > > > >> > > A similar approach can of course also be
> > > applied to
> > > > > >> > > > > > > > MetaModelProperties, by adding the following
> method to
> > > > > >> > > > MetaModelClass:
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > > > > > >> > > public MetaModelProperty
> > > > > >> > > > > > > > > >> > > createShadowProperty(NameSpace ns){
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > > > > > >> > > MetaModelProperty mp =
> > > > > >> > > > > > > > > >> > > ns.getMetaProperty(this.getName(), true);
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > > > > > >> > > this.getDirectInstances.add(mp.node);
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > > > > > >> > > return mp;
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > > > > > >> > > }
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > > > > > >> > > This way the underlying node of a
> > > MetaModelProperty
> > > > > >> > can
> > > > > >> > > > > > properly
> > > > > >> > > > > > > > be used as a class of its own and have properties,
> > > > > >> > relationships,
> > > > > >> > > > that
> > > > > >> > > > > > can
> > > > > >> > > > > > > > be further modeled in the meta layer. This e.q.
> allows
> > > to
> > > > > >> > > > > > > > set a
> > > > > >> > > > default
> > > > > >> > > > > > > > rendering format for a given property class.
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > > > > > >> > > I don't see a MetaModelRelationships,
> which
> > > is
> > > > > >> > > > unfortunate,
> > > > > >> > > > > > since
> > > > > >> > > > > > > > that would allow the modeling of the properties of
> a
> > > > > >> > Relationship.
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > > > > > >> > > Kind regards,
> > > > > >> > > > > > > > > >> > > Niels Hoogeveen
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > > > > > >> > > > Date: Fri, 26 Mar 2010 11:26:29 +0100
> > > > > >> > > > > > > > > >> > > > From: matt...@neotechnology.com
> > > > > >> > > > > > > > > >> > > > To: user@lists.neo4j.org
> > > > > >> > > > > > > > > >> > > > Subject: Re: [Neo] meta meta classes
> > > > > >> > > > > > > > > >> > > >
> > > > > >> > > > > > > > > >> > > > That's an interresting case you've got
> here
> > > and
> > > > > >> > > > > > > > > >> > > > it
> > > > > >> > looks
> > > > > >> > > > to
> > > > > >> > > > > > me
> > > > > >> > > > > > > > like it's
> > > > > >> > > > > > > > > >> > > > probably the best way to model it in
> the
> > > meta
> > > > > >> > > > > > > > > >> > > > model.
> > > > > >> > > > > > > > > >> > > >
> > > > > >> > > > > > > > > >> > > > 2010/3/25 Niels Hoogeveen <
> > > > > >> > pd_aficion...@hotmail.com>
> > > > > >> > > > > > > > > >> > > >
> > > > > >> > > > > > > > > >> > > > >
> > > > > >> > > > > > > > > >> > > > > 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
> > > > > >> > > > > > > > > >> > > > >
> > > > > >> > > > > > > > > >> > > > >
> > > > > >> > > > > > > > > >> > > > >
> > > > > >> > > > > > > >
> > > > > >> >
> _________________________________________________________________
> > > > > >> > > > > > > > > >> > > > > New Windows 7: Find the right PC for
> you.
> > > Learn
> > > > > >> > more.
> > > > > >> > > > > > > > > >> > > > > http://windows.microsoft.com/shop
> > > > > >> > > > > > > > > >> > > > >
> > > _______________________________________________
> > > > > >> > > > > > > > > >> > > > > Neo mailing list
> > > > > >> > > > > > > > > >> > > > > User@lists.neo4j.org
> > > > > >> > > > > > > > > >> > > > >
> > > https://lists.neo4j.org/mailman/listinfo/user
> > > > > >> > > > > > > > > >> > > > >
> > > > > >> > > > > > > > > >> > > >
> > > > > >> > > > > > > > > >> > > >
> > > > > >> > > > > > > > > >> > > >
> > > > > >> > > > > > > > > >> > > > --
> > > > > >> > > > > > > > > >> > > > Mattias Persson, [
> > > matt...@neotechnology.com]
> > > > > >> > > > > > > > > >> > > > Neo Technology, www.neotechnology.com
> > > > > >> > > > > > > > > >> > > >
> > > _______________________________________________
> > > > > >> > > > > > > > > >> > > > Neo mailing list
> > > > > >> > > > > > > > > >> > > > User@lists.neo4j.org
> > > > > >> > > > > > > > > >> > > >
> > > https://lists.neo4j.org/mailman/listinfo/user
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > >
> > > _________________________________________________________________
> > > > > >> > > > > > > > > >> > > Express yourself instantly with MSN
> > > Messenger!
> > > > > >> > Download
> > > > > >> > > > today
> > > > > >> > > > > > it's
> > > > > >> > > > > > > > FREE!
> > > > > >> > > > > > > > > >> > >
> > > > > >> > > > > >
> > > http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/
> > > > > >> > > > > > > > > >> > >
> > > _______________________________________________
> > > > > >> > > > > > > > > >> > > Neo mailing list
> > > > > >> > > > > > > > > >> > > User@lists.neo4j.org
> > > > > >> > > > > > > > > >> > >
> > > https://lists.neo4j.org/mailman/listinfo/user
> > > > > >> > > > > > > > > >> >
> > > > > >> > > > > > > > > >> >
> > > > > >> > > > > >
> > > _________________________________________________________________
> > > > > >> > > > > > > > > >> > New Windows 7: Find the right PC for you.
> Learn
> > > more.
> > > > > >> > > > > > > > > >> > http://windows.microsoft.com/shop
> > > > > >> > > > > > > > > >> >
> _______________________________________________
> > > > > >> > > > > > > > > >> > Neo mailing list
> > > > > >> > > > > > > > > >> > User@lists.neo4j.org
> > > > > >> > > > > > > > > >> >
> https://lists.neo4j.org/mailman/listinfo/user
> > > > > >> > > > > > > > > >>
> > > > > >> > > > > > > > > >>
> > > > > >> > > >
> > > _________________________________________________________________
> > > > > >> > > > > > > > > >> New Windows 7: Find the right PC for you.
> Learn
> > > more.
> > > > > >> > > > > > > > > >> http://windows.microsoft.com/shop
> > > > > >> > > > > > > > > >>
> _______________________________________________
> > > > > >> > > > > > > > > >> Neo mailing list
> > > > > >> > > > > > > > > >> User@lists.neo4j.org
> > > > > >> > > > > > > > > >>
> https://lists.neo4j.org/mailman/listinfo/user
> > > > > >> > > > > > > > > >>
> _______________________________________________
> > > > > >> > > > > > > > > >> Neo mailing list
> > > > > >> > > > > > > > > >> User@lists.neo4j.org
> > > > > >> > > > > > > > > >>
> https://lists.neo4j.org/mailman/listinfo/user
> > > > > >> > > > > > > > > >
> > > > > >> > > > > > > > > >
> > > > > >> > > >
> > > _________________________________________________________________
> > > > > >> > > > > > > > > > New Windows 7: Find the right PC for you.
> Learn
> > > more.
> > > > > >> > > > > > > > > > http://windows.microsoft.com/shop
> > > > > >> > > > > > > > > >
> _______________________________________________
> > > > > >> > > > > > > > > > Neo mailing list
> > > > > >> > > > > > > > > > User@lists.neo4j.org
> > > > > >> > > > > > > > > > https://lists.neo4j.org/mailman/listinfo/user
> > > > > >> > > > > > > > > >
> > > > > >> > > > > > > > > _______________________________________________
> > > > > >> > > > > > > > > Neo mailing list
> > > > > >> > > > > > > > > User@lists.neo4j.org
> > > > > >> > > > > > > > > https://lists.neo4j.org/mailman/listinfo/user
> > > > > >> > > > > > > >
> > > > > >> > > > > > > >
> > > > > >> >
> _________________________________________________________________
> > > > > >> > > > > > > > Express yourself instantly with MSN Messenger!
> > > Download
> > > > > >> > > > > > > > today
> > > > > >> > it's
> > > > > >> > > > > > FREE!
> > > > > >> > > > > > > >
> > > > > >> >
> http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/
> > > > > >> > > > > > > > _______________________________________________
> > > > > >> > > > > > > > Neo mailing list
> > > > > >> > > > > > > > User@lists.neo4j.org
> > > > > >> > > > > > > > https://lists.neo4j.org/mailman/listinfo/user
> > > > > >> > > > > > > >
> > > > > >> > > > > > >
> > > > > >> > > > > > >
> > > > > >> > > > > > >
> > > > > >> > > > > > > --
> > > > > >> > > > > > > Mattias Persson, [matt...@neotechnology.com]
> > > > > >> > > > > > > Neo Technology, www.neotechnology.com
> > > > > >> > > > > > > _______________________________________________
> > > > > >> > > > > > > Neo mailing list
> > > > > >> > > > > > > User@lists.neo4j.org
> > > > > >> > > > > > > https://lists.neo4j.org/mailman/listinfo/user
> > > > > >> > > > > >
> > > > > >> > > > > >
> > > _________________________________________________________________
> > > > > >> > > > > > Express yourself instantly with MSN Messenger!
> Download
> > > today
> > > > > >> > > > > > it's
> > > > > >> > > > FREE!
> > > > > >> > > > > >
> > > http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/
> > > > > >> > > > > > _______________________________________________
> > > > > >> > > > > > Neo mailing list
> > > > > >> > > > > > User@lists.neo4j.org
> > > > > >> > > > > > https://lists.neo4j.org/mailman/listinfo/user
> > > > > >> > > > > >
> > > > > >> > > > >
> > > > > >> > > > >
> > > > > >> > > > >
> > > > > >> > > > > --
> > > > > >> > > > > Mattias Persson, [matt...@neotechnology.com]
> > > > > >> > > > > Hacker, Neo Technology
> > > > > >> > > > > www.neotechnology.com
> > > > > >> > > > > _______________________________________________
> > > > > >> > > > > Neo mailing list
> > > > > >> > > > > User@lists.neo4j.org
> > > > > >> > > > > https://lists.neo4j.org/mailman/listinfo/user
> > > > > >> > > >
> > > > > >> > > >
> > > _________________________________________________________________
> > > > > >> > > > Express yourself instantly with MSN Messenger! Download
> today
> > > it's
> > > > > >> > FREE!
> > > > > >> > > >
> > > http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/
> > > > > >> > > > _______________________________________________
> > > > > >> > > > Neo mailing list
> > > > > >> > > > User@lists.neo4j.org
> > > > > >> > > > https://lists.neo4j.org/mailman/listinfo/user
> > > > > >> > > >
> > > > > >> > >
> > > > > >> > >
> > > > > >> > >
> > > > > >> > > --
> > > > > >> > > Mattias Persson, [matt...@neotechnology.com]
> > > > > >> > > Hacker, Neo Technology
> > > > > >> > > www.neotechnology.com
> > > > > >> > > _______________________________________________
> > > > > >> > > Neo mailing list
> > > > > >> > > User@lists.neo4j.org
> > > > > >> > > https://lists.neo4j.org/mailman/listinfo/user
> > > > > >> >
> > > > > >> >
> _________________________________________________________________
> > > > > >> > New Windows 7: Find the right PC for you. Learn more.
> > > > > >> > http://windows.microsoft.com/shop
> > > > > >> > _______________________________________________
> > > > > >> > Neo mailing list
> > > > > >> > User@lists.neo4j.org
> > > > > >> > https://lists.neo4j.org/mailman/listinfo/user
> > > > > >> >
> > > > > >>
> > > > > >>
> > > > > >>
> > > > > >> --
> > > > > >> Mattias Persson, [matt...@neotechnology.com]
> > > > > >> Hacker, Neo Technology
> > > > > >> www.neotechnology.com
> > > > > >> _______________________________________________
> > > > > >> Neo mailing list
> > > > > >> User@lists.neo4j.org
> > > > > >> https://lists.neo4j.org/mailman/listinfo/user
> > > > > >
> > > > > > _________________________________________________________________
> > > > > > Express yourself instantly with MSN Messenger! Download today
> it's
> > > FREE!
> > > > > > http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/
> > > > > > _______________________________________________
> > > > > > Neo mailing list
> > > > > > User@lists.neo4j.org
> > > > > > https://lists.neo4j.org/mailman/listinfo/user
> > > > > >
> > > > >
> > > > >
> > > > > --
> > > > > Mattias Persson, [matt...@neotechnology.com]
> > > > > Hacker, Neo Technology
> > > > > www.neotechnology.com
> > > > > _______________________________________________
> > > > > Neo mailing list
> > > > > User@lists.neo4j.org
> > > > > https://lists.neo4j.org/mailman/listinfo/user
> > > >
> > > > _________________________________________________________________
> > > > Express yourself instantly with MSN Messenger! Download today it's
> FREE!
> > > > http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/
> > > > _______________________________________________
> > > > Neo mailing list
> > > > User@lists.neo4j.org
> > > > https://lists.neo4j.org/mailman/listinfo/user
> > >
> > > _________________________________________________________________
> > > Express yourself instantly with MSN Messenger! Download today it's
> FREE!
> > > http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/
> > > _______________________________________________
> > > Neo mailing list
> > > User@lists.neo4j.org
> > > https://lists.neo4j.org/mailman/listinfo/user
> > >
> >
> >
> >
> > --
> > Mattias Persson, [matt...@neotechnology.com]
> > Hacker, Neo Technology
> > www.neotechnology.com
> > _______________________________________________
> > Neo mailing list
> > User@lists.neo4j.org
> > https://lists.neo4j.org/mailman/listinfo/user
>
> _________________________________________________________________
> New Windows 7: Simplify what you do everyday. Find the right PC for you.
> http://windows.microsoft.com/shop
> _______________________________________________
> Neo mailing list
> User@lists.neo4j.org
> https://lists.neo4j.org/mailman/listinfo/user
>
--
Mattias Persson, [matt...@neotechnology.com]
Hacker, Neo Technology
www.neotechnology.com
_______________________________________________
Neo mailing list
User@lists.neo4j.org
https://lists.neo4j.org/mailman/listinfo/user
