Jesse Jesse

Hi Guys

I think the 1:1 association between an Equipment and Flight is ok. My reasoning being a flight can only have one Equipment at a specific point in time but this does not stop a flight from having a different Equipment at a different time.

I have read on other posts that people who have changed the cardinality of BDM associations have got as good a mark, if not better than people who have not changed it as long as you justify your assumptions in the documentation.

I see segment and leg as meaning the same thing.
IF I agree with the assumption that a segment simply represents one take off and one landing (departure airport, arrival airport)that is qualified by a flight(flight no. price etc as travel terminology suggests and if I agree with the association between segment and flight as being one to one then this implies that a new class needs to be introduced between segment and itinerary to track a customers reservation for a particular segment including seat reservation etc. But then what's the point then of having an extra association between itinerary and segment?. However if I change my model so a flight can have many segments(Seat reservations for a flight) then in my view - so far, this simplifies the model.

All in all I think this assignment is to ambiguous for its own good. If the concepts where cleanly defined it would save so much bother especially given there is no customer to aid in analysis etc - it kind of puts me off the whole assignment. At the end of the day if our assumptions are properly documented and it supports the needs of the business how can you fail unless of course the examiner wants to see certain terminology defined within the model i.e. segment which I think would be very harsh.


Look forward to your thoughts.

Jesse

Thanks Sri.

That's more or how I understood segment to be, but if we follow a one to one association between Segment and Flight, then it seems a requirement to introduce an additional class between Itinerary and Segment to track seat number etc, as if a Segment holds the seat number the multiplicity between segment and flight needs to be changed as there would be multiple segments related to a flight i.e.

customer1 books segment1 - Krakow to Poland with seat no 12 for flight fr333

customer2 books the same segment, segment1 - Krakow to poland with seat no 112 for flight fr333

Also in this context if the segment only holds the departure and arrival city, no seats etc, then this breaks the business rule implied by the one to 1:m association between Itinerary and Segment as Segment can now really belong to more than one Itinerary, given that introducing a new class also breaks this association.

But if we consider a Segment as a reservation line item on an Itinerary and introduce a Flight Description class (holds flight number departure city, arrival city one take of and landing) that is associated to flight (scheduling of a trip date and time) which models the same semantics as segment and flight. Also I was considering introducing the concept of a FlightPlan and possibly another concept to group flights together to fulfill a journey that takes multiple segments (flights in this case).


look forward to your response


Jesse.

Hi Guys, thanks for the response.

I am still running over all of this in my head trying to come to a solution given that the requirements contain a high level of ambiguity and trying to understand why certain BDM associations are defined as such.

Vagner in response to your post:

I see Segment as a line item on a Itinerary too.
But I see a Flight as flight number, and each Flight has 1 or many Legs.
For instance, Flight 3370 has Legs A -> B, B -> C and C -> D.
Then, Customer X can buy the seat number 14C in the Legs from A to C, and Customer Y can buy the same seat 14C in the Leg from C to D.
I introduced a class Reservation, that associate Segment, Leg and Seat.
What do you think?

I think I see what you are getting at. I think it is something along the lines of what I am thinking of. One question though, will you still have an association between segment and flight and what data would you hold in leg?

From other posts I came across a link defining travel terminology ->

Travel Terminology

After reading this I see Segment and leg as having the same meaning when used in that sense ( one take off and landing). When I consider the one to one association between a Segment and Flight I say to myself why!, as I can't see the reason for it as I consider flight also to have the same meaning as segment one take off and landing. Therefore this implies that a segment given its definition will have the same attributes as a flight for its take off and landing. This raises two interesting choices for me if there is to be a one to one association between flight and segment then flight does not hold the origin and destination only flight number etc and we search on segments using an object that aggregates segments into a route when a customer wishes to search for flights.

If a flight is to hold the destination and arrival then the second option we search by flight and change the association between segment and flight to flight 1 segment 1 ..*. And in this sense, segment is simply a booking line on the itinerary. As a flight can have many segments (seat reservations).


Hi arvind in respone to ur post.

- So there will be passenger details per segment ?
Would this duplicate the passenger info. May be you can put it at itinerary level and still store the booked seat info at segment level.

Yep I was thinking that myself but this asks the question what happens if there is multiple passengers being booked by the same customer. I guess it comes down to how the seat selection is implemented if the customer simply selects coach or first class which I think should probably selected when the initial search is carried out or if there is a more in depth seat selection option that would require the passeneger to be explicity coupled to each section.

Where do you plan to put this higher level object

Here it depends on I guess what I am going to search - either segment or flight, as commented on in response to wagner


Maybe I am missing something simple here ...

Look forward to your responses.

Jesse

Hi I realize this is a very old topic, I have being looking at a few posts, thought I would put my design out there to see if I am on the right track.

Basically I see a Segment as a line item on an Itinerary (similar to the relationship between an order and orderline). The segment holds information such as the flight details - arrival airport, destination airport price etc obtained through its association with flight and also has the seat no, and passenger details.

I see a flight as a trip between an arrival and destination airport i.e. on take off and one landing. Therefore since the flight class represents all flight instances I see there is a need for a higher level object that groups flights together in order to get from point a to point b offering various options to the customer i.e. for indirect flights this could contain two or more flights possibly or direct 1 flight etc.

Any comments would be appreciated

Thanks

Hi I am using Jude the free commerical edition available at http://www.esm.jp/jude-web/index.html. Did try visio and posiedon, however I have found this to be the better of the two so far (easier to use, not as restrictive), allthough have not created a component diagram yet.

congrats steve

Yep, that�s near enough to how I see it - although only just started the assignment so not done too much in depth research and have read a few posts. A segment, flight is taken care of by a single equipment (aeroplane).

I see segment as a line item in an itenerary similar to an order line on an order that tracks the passenger, reserved seat etc. In contrast to reading other posts which show a the concept of segment being a take off and landing between two points. I can't see the point of having duplicate information for departure and arrival in segment and flight. Maybe I am missing something here as have not properly thought this through? But I see having a higher level concept such as route which is an aggregation of flights where each flight provides a means for traveling between two points in order to fulfill a defined route.


Any comments would be great.

Good score, just to follow up on the last post, u say you showed framework classes on the diagram I take it by this you mean open source framworks such as struts action classes for the controller .... if u went that root.

Thanks

Hi

Just wondering is it allowed to modify the supplied BDM model when creating the class diagram i.e. has BDM concepts and structural constraints between the concepts required to be the same in the class diagram. I also take it that you can add new classes to the class diagram to supplement the existing BDM concepts such as inventory, flight etc.

The other question is related to controller classes etc has anybody added these concepts to there class model or what exactly is the class model supposed to show an analysis model or a fully fledged design depicting the classes in the system
.

Any input would be great

Hi all, just read through my assignment, can't seem to find a reference to any specific J2EE version does this mean we can use any J2EE version?


Thanks