6 State Model Syntax AML presently provides no language for defining state model syntaxes. Unless the AML user has a suitable graphical meta-language at hand, the user should define graphical symbols for resources and relations of the resource model in this section. In addition, drawing rules have to be defined (in plain english) that describe how the symbols may be interconnected when creating state models (see also Sect. 1.6.4). Elements of Interactions 7.4.1 Introduction This section identifies and defines all concepts that are needed to understand and describe interactions between service objects. Basic concepts are operation, 7.4 Elements of Interactions abstract service primitive (ASP) and communication event. Secondary concepts are activity and transaction. Figure 7.22 defines the relations between these concepts and properties of operations and ASPs. existsln Communication canAffect Primitive State Event Service (see Fig. 7.42) isInstanceOf Relation (see Fig. 7.2) Abstract *primitiveType{ Service "Request", "Confirm", "Refuse", Primitive "Order", "Offer", "Reject", "Invite", Activity 1..3,5 "ReportInit", "ReportConfirm", "ReportRefuse"} defines Operation refers # *operationName Operation *operationClass{ (see Fig. 7.14) isAsequenceOf "REQUEST", "ORDER", "OFFER", "INVITE", Service "C_REPORT", "U_REPORT"} Transaction "effect{modifier,initiator,selector,analyser) *synchronism{synch,asynch] *atomicity{atomic,notAtomic} *destructiveness{destr,notDestr} o *timeConstraint-temporal - expression o activityTime{CHOICE{absolut, symbolic, standard} o *userDefinedProperty - user-defined Fig. 7.22 Concepts for interaction elements Behaviour is generated by the activities that are performed by service objects. When these activities are referred to in communication between service objects, they are regarded as operations. The key information element that describes instances of the concepts of Fig. 7.22 is therefore the operation specification, see Fig. 7.23. Two forms of operation specification may exist: the symbolic fo