Process Input and Output

The process ontology (DAML) shows the various types of processes we can have.

The LocateBook service is atomic, so we say that its a subclass of an atomic process. We also limit its cardinality to 1:

<daml:Class rdf:ID="LocateBook">
  <rdfs:subClassOf rdf:resource="&process;#AtomicProcess"/>
  <rdfs:subClassOf>
    <daml:Restriction daml:cardinality="1">
      <daml:onProperty rdf:resource="#bookName"/>
    </daml:Restriction>
  </rdfs:subClassOf>
</daml:Class>

Processes have properties associated with them. The input property tells us what the process takes as input. If we want LocateBook to take a book name as input we say:

<rdf:Property rdf:ID="bookName">
  <rdfs:subPropertyOf rdf:resource="&process;#input"/>
  <rdfs:domain rdf:resource="#LocateBook"/>
  <rdfs:range rdf:resource="&xsd;#string"/>
</rdf:Property>

The output property will depend on whether the call worked, and what it returns. Its what DAML-S calls a ConditionalOutput (class).

If the book described by "bookName" is in Congo's catalog, then the output of LocateBook is the description of the book and the prices. If the book is not in Congo's catalogs, then the output is a message to this effect. The output of LocateBook is thus described as a conditional output. We illustrate the notion of a conditional output below in terms of the bookDescription.

<rdf:Property rdf:ID="bookDescription">
  <rdfs:subPropertyOf rdf:resource="&process;#conditionalOutput"/>
  <rdfs:domain rdf:resource="#LocateBook"/>
  <rdfs:range rdf:resource="InCatalogueBookDescription"/>
</rdf:Property>

<daml:Class rdf:ID="InCatalogueBookDescription">
  <rdfs:subClassOf rdf:resource="&process;#ConditionalOutput"/>
</daml:Class>

<rdf:Property rdf:ID="condInCatalogueBookDescription">
  <rdfs:subPropertyOf rdf:resource="&process;#coCondition"/>
  <rdfs:domain rdf:resource="#InCatalogueBookDescription"/>
  <rdfs:range rdf:resource="#InCatalogueBook"/>
</rdf:Property>

<rdf:Property rdf:ID="outInCatalogueBookDescription">
  <rdfs:subPropertyOf rdf:resource="&process;#coOutput"/>
  <rdfs:domain rdf:resource="#InCatalogueBookDescription"/>
  <rdfs:range rdf:resource="#TextBookDescription"/>
</rdf:Property>

<daml:Class rdf:ID="TextBookDescription">
  <rdfs:subClassOf rdf:resource="&daml;#Thing"/>
</daml:Class>