6) Working with Protege

    If you are not acquainted with Protege, this tutorial will provide you with all the knowledge that you need to use the DAML+OIL Plug-in, however more information is available at the Protege site.  See Section 7 for information on current restrictions.

The Protege GUI utilizes the following buttons. 

Their meanings are as follows:

• View
• Create new class, slot, etc.
• Add existing class, slot, etc.
• Remove
• Delete
• Create a copy

    Classes

        New Class

            New classes in DAML+OIL should be subclasses of daml_oil:Thing, since everything is a "Thing" in DAML+OIL.  Follow the instructions for subclassing below, and subclass off of daml_oil:Thing to create all of your basic classes.

        Subclasses

• Creating subclasses can be done in one of two ways from within the Classes tab.
• The first method is to right click on the class you want to subclass and pressing Create subclass

• The other way is to select the class that you wish to create subclasses of, and press the Create Button: at the top of the classes tab.  (The tool tip reads create subclass.)
• Once you've done this you'll have a new class who's name begins with "KB_" 

• You may give your class a new name in the Name field, or leave the name as it is.
• Any class who's name begins with "KB_" will be made into an anonymous class upon serialization.  This means the class will not get an rdf:ID.

    Multiple inheritance

• To add more superclasses to a class press the add button of the Superclasses field at the bottom of the Classes tab.

    Properties (Slots)

           DAML+OIL Properties are mapped to Slots in Protege.  This tutorial will use Property to refer to the daml_oil:Property and Slot to refer to the Protege representation.

        New Properties

• Creating Slots can be done one of two ways from the Slots tab.
• One way is to use the Create Button: at the top of the Slots tab window.
• The other way is to right click on any slot listed in the Slots tab and select Create slot

• The slot has a default name that you can change in the name field

• Now you have a new Slot. In the current version the default rangeType is Instance.  This means that the range of the property will be a class.  We explain below how this can be used to specify properties that have user-defined classes as their range as well as XMLSchema datatypes. 

        Range

• Click on the Add Classes button next to Allowed classes
• Most of the XML Datatypes are available should you desire to use them.  Click on the knob next to XMLSchema:anyType to see the list expanded

• Otherwise you can select daml_oil:Thing or any of its subclasses

        Domain

• Domains are not specified on the Slots tab, instead go over to the Classes tab.
• Select the class that you mean to be the domain of the slot.
• You need to put the slot into the damlProperties field of the class.

• To add a previously created Slot press the add button and choose the slot from the window that pops up.

• To create a new slot for this class, press the create button
• You do not have to specify a domain for any slot, however you might want to use the slot in several places without specifying the domain.  In this case the best thing to do is to add the slot to daml_oil:Thing.  If the slot appears in the damlProperties field of daml_oil:Thing it will be available to all your classes.

        Subproperties

• Protege supports subslots which we will use to map to subproperties. 
• To create a new subslot go to the Slots tab
• Right click on the Slot you wish to use as the superslot, and select create subslot

• Note: Protege subslots are not fully implemented yet.  One thing that you should know is that subslots only inherit things from their parents at creation time.  So if you should update the superslot, the subslot will not change unless you do it manually.  This should be fixed in the next version of Protege.

        Object & Datatype Properties

Properties that have been created using the steps described under New Properties, will be serialized into daml_oil:Property.

• You can create Object or Datatype Properties by changing the metaclass of the Slot
• Right click on the slot that you want to change and then select "Change slot metaclass..."

• Then you can select ObjectProperty DatatypeProperty.

        Additional Property information

• You can change the property's type using the three checkboxes, and you can add or create other slots to fill the roles of EquivalentTo, SamePropertyAs, and InverseOf, if you so desire.

Important things to remember:

• TransitiveProperty and Unambiguous Property are subclasses of ObjectProperty
• If a TransitiveProperty is used in a cardinality constraint, class consistency may no longer be decidable

    Instances^(NEW)

To create view or edit instance click on the Instances tab

First select the class of which you would like to create an instance

Then click the button above the Direct Instances field.

You now have an instance of a class.

You should rename it, since any instance that begins with "KB_" will not get an rdf:ID upon serialization.  If you do not rename it, you may lose your work upon serialization.  Rename your instance by editing the ":NAME" field.

You can add values to the slots of an instance by clicking on the create , or add buttons on the respective field.  (Note:  If your property is not showing up in your instance, then you have not specified its domain properly.  Remember properties with no specified domain should be added to the daml_oil:Thing as mentioned above.)  When you press you are creating a new instance of the type that is specified by the range of the property.  When you press you are adding an existing instance of that type.

        Important notes regarding XML

    When you create instances of XML types, they are actual instances of that type.  For example, the property MyPropertyB has the range XMLSchema:integer.  Supposing that I want to add the value 42 to my instance.  I press the button (unless I alredy have an instance of 42) and select the correct type.

    Then I enter the value that I desire into the :NAME slot of the new instance that appears on the screen.

    Now the value will appear in the field for the property.

    If I had already created the XMLSchema:integer value of 42 previous to this time, I would not be able to create another instance of it (There is only one 42 in the universe and for everything that has the value 42, it is the same 42).

    Instead I would add the value to my property field using the button.

    It will be a Direct Instance of XMLSchema:integer, so I can select it from this dialog.

    IMPORTANT:  Do not edit the value of the instance of an XML datatype!

    Do not view and change the value of 42.  These slots are filled with references to instances.  Since this is a reference to the actual instance of 42, changing its value has the same effect as changing the value of 42 everywhere in the ontology.  If one were to view and change 42, to 43, the value of 42 is actually changed to 43, and all references to 42 will continue to point to the same instance which now has the value of 43. 

    Instead of doing that, remove the value from the property using the button, and create a NEW instance of an integer to take it's place.  Removing the instance does not delete it.  It only removes it from the slot.  It can still be referenced elsewhere in the ontology, and those slots will remain unchanged.

    Restrictions

Restrictions are created from the Classes tab.  In the DAML+OIL plug-in there is a field in each class for Restrictions.  In that field you can specify a Restriction, and on serialization the Class will be a subclass of all the Restrictions listed there.

• You create a new Restriction by pressing the Create button of the Restriction field
• Then select the type of restriction you would like to create.  (See Qualified Restriction below for the other kinds of Restrictions)

• You'll then get a window that looks like this

• Select a slot that you would like to put this restriction on by pressing the add or create buttons next to onProperty
• Then enter a value for the restriction
• If the restriction is a cardinality restriction, then you'll be able to put a number in the value slot
• Otherwise you'll be able to select the appropriate type of object by using the add or create buttons.
• When you close the Restriction's window it should show up in the Restriction field of the class.

        Qualified Restrictions

• The Restrictions cardinalityQ, minCardinalityQ, and maxCardinalityQ were unavailable to you in the Restrictions field, but you can enter them in the Qualified Restrictions field.  The only difference is that this time you must enter a hasClassQ value.

• In the Class window you should get something like this

    Boolean Combinations (Logical Definitions)

The boolean combinations unionOf, intersectionOf, and complementOf, and further class elements such as disjointUnionOf, oneOf, and disjointWith, can be added to a class from the Logical Definition field in a similar manner to the way Restrictions worked.

• Press the create button
• Select the type

• You'll get a window that looks like this:

• Press the add button to add one or more classes or the create button to create a class on the fly.
• First you'll have to select the type of class that you are trying to add
• Note all user-defined classes that are not Restrictions are under "Class"

• You should end up with something like this

    Miscellaneous

As you have probably guessed SameClassAs and EquivalentTo map to their respective DAML+OIL tags.  You can add or create classes for those slots using the buttons above the fields.

The daml:Ontology can be accessed from the Ontology Class under the Classes tab