Specification of IT Systems Mandatory Exercise Week 4Group 3, Søren Vestergaard, Smari Waage, Belma Boyraz, Jannick Hoy

State table - event/action

Event Current state Action Next state

request reservation(t, u) NotReserved(t, u) validate(t, u)

validate(t, u)reserve(t, u)

validate = falseNotReserved(t, u)

validate = trueReserved(t, u)

cancel reservation(t, u) Reserved(t, u) confirm(t, u)

confirm(t, u)cancel(t, u)

confirm = falseReserved(t, u)

confirm = trueNotReserved(t, u)

State transition diagram

State diagram - descriptionReserve

User clicks “reserve” on a travel element from his list. Date and time are validated for overlap between this and other possible

reserved elements. If the validation succeeds, the element is reserved for the user, otherwise

it stays unreserved.Cancel

User clicks “cancel” on his list of reserved travel elements. User is asked for confirmation. If confirmed, the travel element is cancelled, otherwise it stays

reserved.

Assumptions about the environment

User might be interested in travel elements and/or packages from advertisement

Web services are online and functional

State table - stimulus/response

Stimulus Current state Response Next state

request reservation(t, u) NotReserved(t, u) validate(date, time)query webservice(t,date, time)present reply(u)confirm(t, u)update webservice(date, time, t, u)inform user(t, u)

validate = true &query webservice =accepted &update webservice =accepted

Reserved(t, u)

NotReserved(t, u)

cancel reservation(t, u) Reserved(t, u) confirm(t, u)update webservice(date, time, t, u)inform user (t, u)

confirm = true &update webservice =failed

NotReserved(t, u)

Reserved(t, u)

Make travel package

System engineering argument

Assumption The relevant web service is online and functional

Current state Travel element is not already reserved by user

Stimulus User chooses to reserve a travel element

If all of the above are satisfiedA travel element is reserved for a user