Note: I have delayed the due date
Contents
1. If using Unix and NT it is not easy to have a program print directly to the printer For Cmpt 275 I will allow you to instead just write to a file then tell the user in the manual to use a DOS or MS Windows command to get the file printed Marking You will be marked out of 50 using the following distribution 5 marks Release pages and consistency with other CSCIs and Architectural Design Document title revision history and table of contents pages 10 marks Excellence of design description of design justification of design choices 7 marks Correct use of diagrams and scenario descriptions pseudo code 5 marks Main and source file history and general top module comments 3 marks Function prototype comments parameter and general top comments 10 marks Test cases each with 4 parts what being tested exact pre conditions exact steps and exact expected results i e simulated screen or printer outputs 5 marks Organization and neatness choice definition and consistent use of coding and commenting convention order of listings bursting of listings labelled tab dividers 5 marks Spelling and grammar aimed and worded at correct audience Page 13 of 16 Addendum on File Iterators When doing your design many students in the past have had a hard time knowing how to struc ture a program that needs to get every record from a file Perhaps this is needed for a displaying all records so the user can select one or perhaps it2. design gap decide on a number of design issues and document why you made the design choices you did by comparing to an al ternate design You will also have to compare files space for two different designs depending on the semester project this might be a 2NF vs 3NF calculation or a roll up vs split inherit ance implementation And you will decide on a team coding and commenting convention then write and compile the main module which may or may not be particularly long and write the C header files or Java classes without function bodies for the other modules that you feel will be needed You will NOT write the function bodies except for the main function and you will NOT link or run your program You just must get a clean compile of the main module and implicitly any h files it includes and for the other modules just supply uncompiled inter face h files In the case of Java you MUST compile the other bodiless class files as that will catch any obvious interface syntax errors Warning Student Assignment 3 s prior to 95 2 that may be provided as examples in the SFU Library Reserves did not use the trace union technique so be careful not to copy their design derivations and sections topics formats directly Whenever you are writing remember to ask yourself who your target audience is In the case of a design specification it is neither yourself nor your 275 instructor The fact that you are a de signer on a big project
3. I O etc out of the chart to make the diagram a little simpler Leave room at the bottom for pseudo code scenario descriptions Make many copies of the resultant diagram You are to hand in one single scenario OCD collaboration diagram for each scenario You may hand draw the call traces on each scenario collaboration diagram and hand write in the pseudo code description on the bottom of the single scenario diagram or on the next page Make sure you label the arrows with the call precedence number If possible show these num bers within the pseudo code Discuss somewhere in your design document which modules will be responsible for initializa _ tion shutdown of others Where in the hierarchy can decisions to reset or end the program origi nate How will any necessary initialization and shutdown control be signalled throughout the OCD to each module needing it It is considered bad design if one module calls and therefore knows about all the others each module typically knows only about the few below it or beside it 5 Draw an overall OCD by taking the union of all the single scenario collaboration dia grams Remember you will not need sequence numbers The overall OCD will determine the services functions required to be exported from each module In the new drawing show the module icons like the following Module Name procNamel ee procName2 yee procName3 The gap in the middle of the object represent
4. easy to get a listing that proves your main and source files compile If you find a way sometimes asking for a compilation listing with line numbers and no error messages showing please tell me So in order to prove your code compiles do NOT try to build or make you must supply a floppy disk of all your code Attach it firmly to the inside cover of your assignment or buy a special plastic 3 ring holder to hold it in your 3 ring binder Or scotch tape an envelope onto the inside cover of the binder put the floppy in the envelope and lightly seal it with a bit of scotch tape Note that some languag es do not have the concept of an interface header file e g Java and possibly Visual Basic But you can write the classes or modules and not give any bodies to the functions yet And Java has a neat tool to extract the prototypes and special comments from an implementation module NOTES In your spare time though you are not supposed to think about implementation at this point one team member could start some experiments trying to call the operating system trying to open and use binary files with fixed length records try overwriting a record in the middle of the file or whatever else you are going to require support for For C programmers there is informa tion on random access binary I O available in file advanced io pdf on the class web site These preliminary implementation tests are a good task to assign to a systems programmer
5. four functions for each class module that is controlling a particular database file you will allow the scenario control functions to properly orchestrate a user command Note that some teams occasionally try to create one file management class and have multiple instances of it one for each database file That is not trivial for 2nd year students so I advise you do it at your own peril You may want to have one of your expert system programmers write one java class that fronts for a database file She can show it to others and then each of them can write a similar module class for their database file Thus each student gets the experience of writing random access bi nary I O functions but the team generally has to only waste time struggling with writing the ini tial one The reason we have a module or class front for a file is that the file format and organization may change in the future and we do not want this to affect the rest of the program E g instead of having unsorted records in the file we could have sorted ones or a B tree for faster access The rest of the program should not be affected by such implementation changes if they are hid den from other modules programmers by a nice module or class interface that provide adequate general functionality as described above Page 14 of 16 Classes Fronting for Persistent Records Students in 2nd and 3rd year often have trouble with the concept of file records First they are temp
6. global constants That way by changing the 30 above to 40 not only do you increase the size of the array but also change the limit of all loops that traverse that array Note 1 Do not put all the global definitions in one h file Instead put each one in the h file or class to which is most related Note 2 Often students like to put constants highly related to a C class inside the C class itself Then you refer to it the same way you would to an attribute variable in the shep herd s brain This is good cohesion But if you need these constants at compile time to dimen sion the size of arrays C generally restricts inside constants to be integer only See the document classConstants pdf on the Cmpt 275 web site if you are working in C Note that in Java it is possible to advertise global constants in an interface file Example Table of Contents for the Architectural Design Document Don t forget the 3 release pages and other revised documents that come before this one in your assignment submission Don t forget to turn on change bars before revising the previous docu ments And don t forget the labelled tab dividers before each document 1 Architecture Document Title Page ii Architecture Document Revision History Page iii Architecture Document Table of Contents Page Page 6 of 16 The following provides hints for what I would like in each section of the Architecture Design Document You may assume the
7. is for getting them out of the file so that you can select a subset of them e g all cargo items scheduled for a particular flight or perhaps it is for a printout where you want to compose and print one line at a time In any case the proper concept to use is that of an iterator Iterators can be fancy objects in themselves however you probably just need a couple of plain C functions perhaps not even in a class or a couple of java static functions in each class that fronts for a database file The two functions typically needed are moveToBeginningOfFile getRecord The first does what its name implies The second reads the record currently pointed to by your file module and returns the data in an object instance The read implicitly has the effect of moving the current position in the file ahead by one record These are not direct random access file library functions they are meant to be functions your module class exports to other programmers on your team so they can access your module s class s records You will write these functions by calling the underlying random access binary file i o library functions provided by your programming language You might also want to provide a few other functions like AddRecord that takes an class in stance say ChangeRequest as a parameter and throws it onto the end of the database You may also need a function that deletes the next record from your current position By providing these
8. not have a lot of instance oriented nature to it many informations systems do not If you make yours instance oriented you will have to work at figuring out where you are going to create use pass around and destroy instances In Cmpt 275 Assignment 3 you have to choose between some of these alternatives that s what design is There are three well known types of classes boundary classes scenario con trol classes and persistent entity classes If you are going to write an entity class that some one else on your team needs to call then in Assignment 3 you must decide on your class s software interface Are you going to use static functions or not How exactly What are the functions going to be named What kinds of things do they pass in and out Should your team mates not use any RAM objects after they have been written to disk because you have deleted them What functions are you going to provide for moving forward and back in the file Is your whole team going to use the similar strategies for all the entity classes in your project Addendum Returning Base Type Parameters In Java you can return parameters by reference if they are instances You pass an instance to a function parameter the function can mess with the instance and when the function returns the caller finds the instance modified However it is very hard to do this with Java base types like int float boolean If you want to return one of these you can
9. that needs an architectural design phase means that it is unlikely you will do the low level design coding or testing yourself Instead assume you will have a team of coders and testers on your project staff to do the low level design and implementation So you are old gray haired and wise to the ways of good design and software engineering of big sys tems And you are to use that wisdom to do a good maintainable not brittle design and to communicate it definitively to your staff via your design document and some well documented by function bodiless code The target audience low level designers coders design review in spection test personnel maintenance personnel who may look at the architectural spec to ori ent themselves to where things are in the system and your boss the director of development in your company You may assume all readers have read the requirements spec and user manu al By the way I have met project managers who rejected high level design specs not because the design was incorrect or sub optimal but because it was poorly documented and thus hard to review for correctness and sensibility Page of 16 Also assume you are going to do the design and you have been told you are then going to be transferred to England Your document should communicate your design definitively enough so that the low level designers and coders will not have to keep calling you in England It will also be accompanied by enoug
10. with any tricky use calling or exception details for that function Do not comment about how the func tion works internally only what abstract service it provides to other programmers that might call it By the way in semester 93 2 a student sent me the following e mail message How much do we have to comment For instance I have a procedure called InitMenuBar I can t see how much clearer I can describe it Does it need a descriptive comment My an swer was Dear Student Does your procedure just initialize it or also create allocate it possi bly returning the exception out of memory and or actually display it Russ This illustrates how hard it is to extract yourself from what you know about your own design in order to comment for a maintenance or client module coder who doesn t know what is in your mind The best policy is to pretend you are going to give your code to your best friend then leave the country Assume he is new on the project and has only skimmed the requirements spec and user manual How would you comment for him her Anyway here s an example of Page 10 of 16 kind of coding and commenting style I want It is in Modula 2 but Iam sure you will get the idea Note that the comment delimiters in Modula 2 are and Page 11 of 16 E ExampleSort It is also good lar change was made by R Tront Modified by Joe Smith to add third parameter to p
11. 4 but students always seem to code first rather than in parallel then write the tests just before the Assignment 4 deadline So to prove to yourself that writing black box test cases can be done before implementation code in Assignment 3 you are to hand in 3 black box test cases You don t have to supply a battery of tests which will completely test the system or even fully test a module class I only want you to demonstrate that you can write one functional test case one stress test case and one performance test case These must be complete stating what kind of error each test tests for the exact pre conditions of the test exact input files state mode you are presently in and or what you typed to get to the present state mode exactly what you type in or do to accomplish the test and exactly what actions outputs you expect from the test likely an example of an expected output screen printout or resultant file contents And I mean EX ACT Page 8 of 16 Source Code The source code is NOT part of the Architectural Design Document Each module is a sep arate Computer Software Configuration Item CSCI Each CSCI must be mentioned in its own row in the Release Table and separately put into the back of the release binder with a labeled tab divider Each CSCI including source files must be separated from the others by a labelled tab divider You will loose marks for neatness if you do not include these dividers between e
12. CMPT 275 ASSIGNMENT 3 02 2 DUE DATE At START of class on Friday July 5 2002 Note I have delayed the due date by two days to Friday because the midterm in Cmpt 275 and many of your other courses is in this time period However there are several disadvantages of this One the last assignment debugging and final report will have to be shortened to just 12 days duration Two if you cannot hand this assignment in on Friday before 4pm you will loose 15 not just 5 because Monday is 3 days later than Friday i e 5 penalty PER day Note there is some very interesting and important design hints in the three addendums at the end of this assignment The first two are very important Note Before editing your Assignment 1 or 2 to reflect any changes in the design during this assignment be sure to accept all the change tracking annotations from your previous assign ment 2 changes This deletes the change tracking so that further changes will only show the changes since you handed Assignment 2 in In this assignment you will do the architectural design the internal software interface design and write a few test cases don t forget these I will not ask you to do a complete design speci fication document as your project is not really large enough to warrant subsystem and process distribution issues But you will have to go through a smaller design process based on use case implementation collaboration diagram traces to span the
13. R modules This is easily documented with extremely well comment ed interfaces files In C these are header files In Java these will likely be classes with empty function bodies though java does have an interface concept it is only for instances and therefore cannot document static attributes and static methods Once these are all available at the end of Assignment 3 then in Assignment 4 other team members can immediately begin writing their module s implementations with statements which call your module appropriately The team call all work at coding in parallel at the same time If the interfaces are well de signed and don t reveal a lot about the internal implementation e g list vs tree the resulting implementation modules will be fairly abstract self sufficient and adaptable By exact interface of a modules I mean the interface another programmer needs to know e the names and return types of all exported functions and constructors e the number type and name of all function parameters e the exceptions that might be thrown by each function e names and types of any global constants e name and types of global variables global variables should be rare e names and definition of named global types and classes quite common so others can send your functions the right type of parameters e other things like name and format of shared files usable by other modules By global I mean exported to known to
14. ach CSCI the only exception to this rule is that you needn t divide the separate C header and implementation source listings of the same module The written documents of your as signment should be first followed by the main module source listing then the rest of the list ings in alphabetical order If using tractor feed continuous paper the included listings MUST be burst torn into separate pages so they can be easily read while bound otherwise you will loose marks for neatness Each source code module is to have a certain commenting and coding format I will specify some of the commenting that is required Your group is to specify the smaller details of your coding convention in your main source file comments This will provide the needed revision information informative commenting and a uniform look to all modules even though they might have been written by many different coders Studies have shown that a common coding style in a company increases the speed at which others can read and understand your code The things to agree on are a how to divide major sections of a source code module b the com menting of modules and functions c the capitalization of type variable procedure names d spacing indenting and e the revision history format and order a Each major section of a listing should be separated by a dividing comment line e g ae or KKK KK KR ee eK KK a KK KK KK See my examples below Pick one sty
15. and purpose of each module and possibly point out any layering major abstractions co hesion and fan in present Discuss the design decisions you made and how they affect the visual nature of the diagram i e added or merged modules Keep in mind Section 4 0 below In a paragraph each discuss where you will put the menu state machine code and why Some students even put the main menu stuff in one module and distribute the submenus to other control modules I do not think this is better or worse the nature of your overall scenario design strategy and scenario control location policy either distributed in a roundabout manner distributed in a principle object rooted manner centralized in the UI or scenario modules or centralized in principle object modules Why did you choose this architecture Present the list of scenarios that the system must handle and then attach the many single sce nario collaboration diagrams alternately you could use UML sequence diagrams if you wish Don t forget each must include a scenario description possibly in pseudo code form Discuss which modules need initialization shutdown and describe show which other modules are re sponsible for triggering or passing on needed initialization shutdown control signals 4 0 Comparison with Alternate Design The only way I have been able to get students to actually consider design alternatives which is the essence of design is to insist they provide an al
16. at least one other module The interface then contrib utes to the export space dictionary pool of program elements which any other module s pro grammer could choose to import include use This space could be very large in sloppy C where most things are global unless you take the trouble to declare them to be static There will be some of Russ Tront s Cmpt 212 notes on C scope near the back in coursepak B listed under Tront Even Java programmers might want to read this however Java tends to control its scope just with class private protected and public keywords where as C additionally uses the keyword static for scope as well Note that the keyword static has 5 meanings in C depending on context and some of them in particular as I am discussing here have noth ing to do with the way that Java uses the static keyword Note that Java has another kind of Page 2 of 16 scope called package scope which is indicated by the lack of any of the private protected or public keywords you can see sections 7 5 and 14 of my Jcourse lectures in http www cs sfu ca CC 101 tront lectureNotes for more info on java scope Generally you should choose to export a minimum of entities and you will loose marks if you do not restrict scope appropriately Don t export functions that are not needed outside the module they are defined in and for each non functional item exported y
17. d worry about what are the cohesive chunks of the system i e modules and classes and about what functionality each needs to provide to the other chunks of your team s program Concern yourself with how the nature of the interface and coupling between modules will affect the organization architecture and cleanliness of the system design Function calls are mainly used to send in and or receive data from an abstraction To deter mine the list of procedures required to be exported from each module or class use the union of all use case scenario traces to determine what services are needed by the various clients of a particular module Then give the functions exact names and think about WHAT info should be passed and the DIRECTION parameters need to go in only in out pass by reference out pass by reference or function return value You MUST comment in the prototypes in your header files or in your java class files whether parameters passed by reference or pointer are Page 3 of 16 in out or just out other programmers should not have to scan around the code to find this out Finally decide what a suitable type would be to serve as the INTERFACE representation of each parameter passed in each function call To start 1 You must identify all the modules that will participate in the Object Communication Dia gram OCD Before doing so it is best to decide whether some entity objects in your ORD might not be present in the im
18. e instance needing saving To get the record for a customer named Russ Tront do you construct a RAM instance and set the customer name attribute to Russ Tront and then tell the instance to find its data on disk The instance function then goes and reads the file until it finds the one with the correct name and then reads the other attributes of that record into the other instance attributes of itself Or do you call a static function and pass it the string Russ Tront It constructs fills and re turns an instance Question In C do you want this returned by value or by reference Or to you create an instance set the name attribute to Russ Tront then pass the instance to the static function by reference The static function will read the file and restore the attributes of the instance from disk then return The calling function will now notice that the instance s at tributes are all properly restored from the persistant store on disk Page 15 of 16 In fact I would not take marks off if a student team did not have entity class instances at all You can read a record with a static member function that returns the attributes in multiple pa rameters And you can pass all the fields of say a customer record each in a separate parame ter to a static member function for writing to disk What do you need instances for I am not saying this would be best but it is not horrible You might find that your 275 project does
19. er they definition t what it does suggest what advertisement Note that yo are not END ter ar i in xa or exported ExampleSort OtherProc he parameters of a procedure should be listed one per line as shown above is an input parameter ut parameter giving info on whet a what ther it or solely an outp VAR ref pointer paramet here should be at how to use it ternal algorit only how anot u do not least during interface design Page 12 of 16 ters or not a 1 paragraph description of the procedure its restrictions are hm a procedure will use ther programmer should use an exported procedure t procedures that is being hidden abstracted data to be sorted is ta may in future need d also mention in 1 nature of the you may document units here too if inches or meters and given sorting an input and You can t tel 1 After each etc This int procedure You do not have terface file is have to document why will use a different strategy depending on already returns this simply by EO an Assign good descriptive names to all exported program entities modules files And if possi ble use C reference types rather than pointers for in out and out parameters Compilation Modern development environments don t make it very
20. g a whole function after the signature before the first statement n Java you may put the general comment about a function above the function This is because unfortunately a comment extraction program called javadoc which automatically writes beautiful documents for a class requires that the comment describing a function must go above the function signature in special delimiters You do NOT have to learn to use these special delimiters though it is really interesting to do so and I bet that at least one group will hand in the javadoc for their classes rather than the source itself Java programmers should put a thin dividing line comment then the function comment then some short end of comment indicator e g so readers can quickly find the signature below an indefinite number of comment lines am going to insist that you put each function parameter within a signature on its own separate line Each parameter line will show the parameter s formal name its type and its parameter direction either in in out or out See the example below If necessary each parameter s line should also include the unit of measure for each parameter e g radians or degrees Celsius or Fahrenheit if this is relevant Don t bother to state the unit of measure for a storage module whose parameters simply take data in for later retrieval and output Why The comment for each function signature will describe what the function does along
21. h explanatory text and comments justifying your design espe cially as compared to other alternative designs so that they will not be tempted to change your perfect design You want to prevent them from changing or wasting time thinking about changing the design to a different one that you have already ruled out for good reason The rea sons may not be apparent to them at first glance unless you point these reasons out The end of the architectural portion of this assignment results in the documentation of each individual sce nario implementation and why you chose your trace implementation vs alternatives and an overall Object Communication Diagram Obviously this will include added reactive software modules possibly representing classes other than just the classes corresponding to your data base entities Note that an implementation normally has 3 kinds of modules or classes data base entity related ones orchestrating control ones and so called boundary ones Boundary modules or classes are user interface or system I O related e g a special class of GUI dialog box or a class module that handles incoming network packets These classes provide the functionality at the outer boundaries of your Level 0 DFD The next portion of the assignment is internal interface design I believe the goal of internal in terface design should be a complete definition of how each module appears to programmers which are coding OTHE
22. his may include estimates of database size relative frequency of operations on certain mod ules and required access speed for specific modules The requirements spec only spoke of these things for the overall system This section will have broken things down to the individual module level The coder will know for instance that if inserts to and deletes from collections are very frequent compared to inquiries and modifications sorted files are not very desirable You could also give book or article references to any great algorithms for particular calcula tions that will be needed For Cmpt 275 you can leave section 7 0 out or just simply say that for the prototype files can be unsorted and use linear search which is actually all I expect in Assignment 5 remember the goal of Cmpt 275 is not to make a hot product but to experience a project 8 0 Testing The testing section would normally suggest test strategies to be used or test coverage suggest ed You in CMPT 275 should change the section title to Test Cases and include 3 detailed test cases as mentioned below Test Cases If test cases have not been covered yet in the course they will be very soon They are in Sec tion 7 10 if you want to assign someone to start writing these right away I have a hard time to get students to write black box test cases before they write the code In in dustry this is often done in parallel with low level design and coding 1 e Assignment
23. lasses now unless they are private in scope This is because another module that instantiated or subclassed your class could get access to the non private attributes and that other module s programmer may want to start using your class soon However that pro grammer need not know about how you store entity attributes on disk He she only has to know the non private instance and static attributes in RAM which he she might use because you have not made them private 8 Begin detailed interface design by writing on paper or in the h file the procedure pa rameter lists for each exported procedure and decide the directional nature of each parameter in only in out or out only Define the representation of each user defined global type global variable and each functions formal parameters Also give widely used types a type name or constants a name e g const CUSTOMERSIZE 30 typedef char CustomerArray CUSTOMERSIZE A programmer defined type name like CustomerArray above can be defined once in a particular header file which one then exported to everywhere it is needed Then if this type should ever have to change say change CustomerArray to a C String class then it likely only need be changed in one header file and this will perhaps smoothly affect all the other modules that include it Note that it is also good to define constants that might be used in sever al modules for loop limits or screen output widths as
24. le and all members are to stick with it Actually better yet use rather bold dividers for major sections e g beginning of constants and types beginning of static functions beginning of instance functions and use less bold ones between each function b Each module will start with a comment stating that file s name then have a Revision History section Agree on the revision history format and chronology oldest first or last The next section should be a paragraph long comment describing the purpose of the class module What group of functionality does it encapsulate It is important to state the nature of the cohesion of the module or the nature of not implementation of the data or control abstraction retained by hidden in the module You may also mention any general rules as to how the module should be used e g You must call CreateStack before you can use a stack In contrast advice that is specific to only one function should go in the comments of the individual functions Again see my example below c You need a name spelling and capitalization convention I will accept any standard you propose but the whole project must use exactly the standard For instance is the first letter of a type or class always upper case Is the first letter of every embedded word in a variable name capitalized Are names of constants completely uppercase d Finally you need to decide on an indenting spacing and punctuation conven
25. ou should justify its need to be global by ex plaining in a comment in the C header or Java class file what other module might need it and why C programmers in particular are warned that we will be watching to see if you in particular know how to restrict the unfortunate default global scope of functions and variables not inside functions or classes in C C programmers should make sure they read my Cmpt 212 notes on scope Also your language may throw exceptions when you read to end of file and for other prob lems You may even what to program your own exceptions One of the purposes of excep tions is to be able to write a module that detects a problem like end of file but doesn t know what to do with it but forces the caller to either deal with it The calling function often doesn t know how to detect the problem but it knows what to do about it More than any other lan guage Java forces you to catch or declare the throwing of exceptions A least a couple of peo ple on each team should understand exceptions preferrably all of you If you need to learn more see http www cs sfu ca CC 101 tront lectureNotes Jcourse s12 exceptions pdf The interface design also includes instructions and restrictions on how importers should use a module s exported elements e g whether the initialization function should be called before all the other functions listed in the header file Or that the global variable Done should never be changed b
26. p 2 Abstraction dictates that we try to hide the persistent i e disk storage of vehicles car go items whatever applies in your semester of all types each in their own single module So for the time being think of both superclass and subclass items as being together in one mod ule In Assignment 4 you can refine how this is handled roll up roll down or split Note students often make a mistake here about what their later implementation will be like which wrongly dictates some aspects of their architectural and interface design They wrongly assume that on program start up they simply open and read in all the data from a file and store it in a linked list in RAM You must consider that the data files might be large and will not fitin RAM Also what would happen if the power failed while the updated data was in RAM You must learn to read and write individual binary records in place on disk You must use random access binary I O for all your files in Cmpt 275 The instructor has notes on the class web site on how to do random access binary I O in both C advanced io pdf and in Java BIOJava rev 11 pdf At least two of your team members should start reading these right away Though you won t use these techniques until assignment 4 the fact that you will be us ing them somewhat affects how you should do your design in Assignment 3 Also in some semester s projects you may find that adding derived attribute
27. plementation So do some calculations to decide which file de sign uses less space Depending on the semester s project this may be a 2NF vs 3NF compari son or a roll up vs split comparison Semesters other than 1993 3 Re do the space calculation you did for the retained data in the requirements spec but this time use 2NF Show in your design document which uses less 3NF or 2NF and the assumptions underlying your conclusion If 2NF uses less space and you don t think the time and trouble of entering maintaining redundant data is a problem you would elim inate the 3NF objects and use 2NF In fact for Cmpt 275 use 2NF anyway even if it uses more space because it will make your 275 project simpler You must show the 2NF calculation and state which uses less space but your reason for choosing 2NF can be the instructor told us to use 2NF Semester 1993 3 Calculate the space needed for 1000 cargo items 10 of which are pallets Do this calculation assuming roll up then compare it to a calculation using split In an appro priate section of your design document show the calculation indicate the assumptions underly ing your conclusion do not assume the reader has read this assignment sheet and state which uses less space If roll up uses less space use it and say that is why If split uses less space in dicate that but state you are using roll up because to save the programmers work the instruc tor told us to use roll u
28. reader will have read the requirements spec and the user man ual Remember write and include what you wish a project manager would leave you if you were a coder about his wise high level design before heads to England 1 0 Introduction In a paragraph introduce the reader to the application and mention the other existing docu ments that he should refer to for background info In the second paragraph describe the pur pose of the Architectural Design Document Mention that much of the interface design is not located in this document but available by referring to the actual source code modules that are part of the release Put these source listings after yet further labelled tab dividers in the back of the assignment binder and make an entry for each in the project release table Put a labelled tab divider in front of each class or module s source files 2 0 Refinement of the Analysis Models In a big project this section might show further decomposed DFDs added sub states etc However for Cmpt 275 all I want you to show is the calculations for disk space for 2NF vs 3NF or roll up vs split whichever is appropriate for your semester Also show and discuss the reasons for any derived attributes you may have added recently to improve the performance of certain operations 3 0 Architecture Presentation and Discussion Present the overall OCD i e union of all collaboration diagrams Very briefly describe the name
29. rite an instance to a file Q to what location in the file e A function to fill an instance overwrite its RAM attributes from a record at the current position in the file Et cetera There are many strategies to read and write the file First you can write in binary fixed length records or use Java s Serialization functions which produce variable length records that have a number of drawbacks Note in C writing structs and non polymorphic class instances to disk in binary is quite easy just give the write function a pointer to the first byte of the instance and the number of bytes to read However if a C class has virtual functions or any of its an cestor classes have virtual functions then there are sneaky hidden points in the instances that point to virtual function tables If you write these to disk and read them back another day the virtual function table will not likely be at the previous location In Java writing in binary is much harder that simply writing structs in C C see BIOJa va rev 11 pdf advice written by a previous Cmpt 275 TA However Java does have some nice libraries for accessing different types of formal databases In Cmpt 275 please use the tech niques shown in BIOJava rev 11 pdf Second are you going to use static functions or not e g To write an instance to file do you call an instance function and tell an instance to save itself Or do you call a static function and pass it a reference to th
30. rocedure Sort to document WHY a DEFINITION MODUL Revision History Rev 2 90 02 11 Note particul Rev 1 89 03 19 Original This module procedure is called qualif mostly sorted already to change depending on the dat the module header comment these procedures and other at cohesion F in ied by a flag as The algorithm used for unsorted dat tabase size addit hides the implementation of the sorting algorit thms The exported CO tribut Cmpt tion to what whether the 275 You shoul ther i e the s are tog IMPORT or include s tatemen ts go here Exported constants types variables TYPE Sorted Almost NotVery self explanatory WasAlready OK OrNot indicates whether array was already sorted zj PROCEDURE Sort VAR data ARRAY OF INTEGER in out sortedness Sorted im this parameter is a hint to the sort routine VAR already WasAlready R OUER A Fa Sort is a usef information via whether the data whet relevant or e g i e ul procedure which will sort an integer array the second parameter is almost sorted already her the input array was already sorted Variable didn t need not PROC CAST with HE DURE a comment output parame wheth
31. s to some of the objects may allow a considerable increase in performance Actually you may already have put some derived attributes in your requirements spec There may or may not depending on the semester be opportunities for more For any that you could potentially use you must discuss their advantage over not using them 3 Your OCD will contain a main module one module for each entity class in your ORD and possibly UI and or scenario control modules To decide whether to include the latter mod ules first decide on where you are going to implement your menu code in the main in a UI Page 4 of 16 module or split among main and scenario modules e g perhaps a sub menu in the scenario module that implement the use case operations from that sub menu Document in your de sign document why you chose the menu code placement you did for this project compared to some other alternative Then you will want to decide the following 3 design issues in conjunc tion with each other whether you are going to use centralized scenario control roundabout control or principle object control whether you will use special mid level control functions modules added specifically to contain the scenario orchestration code what UI library scope you are going to allow Document why you made your particular choices in comparison to other options 4 Lay the module icons out on a blank OCD You may leave system provided modules such as file
32. s the place that we put the attributes if we wanted to show them we don t here as we are concerned only with functional services in this part of the design process You may want to draw the call arrows to the correct function name as shown above then you don t have to label the arrows with procedure names If this conven tion becomes too spaghetti like use the other side of the box too or revert to arrows labelled with function names that hit the module icon anywhere on its perimeter Optional If you want you can now additionally put these functions names into the bottom section of the class icons in the ORD shown in the prototype section of your requirements spec 6 Agree ona coding standard see more below You can document this coding standard either in your design spec or as comments at the top or bottom of your main program Most Page 5 of 16 Cmpt 275 teams choose to put it at the bottom of their main module Make sure you decide how you are going to document the revision history of each module in the comments within that module 7 Start writing the interface C h or Java class files At the top of each write a sen tence or two describing each module or class s general purpose exported services and what it contains hides e g Abstract Data Types sub menus user I O More information on comment ing is supplied further below By the way you should write the class instance and static at tributes in your c
33. ted to read them all into a linked list in RAM like Cmpt 201 This is usually incorrect for a large database like file Second they don t appreciate that there is no use converting a four byte 2 s complement integer to a variable length up to 10 byte ASCII or UNICODE string for storage in a file then changing it back to 2 s complement when it is read back in what a silly waste of conversion effort and space Third they usually do not have experience doing ran dom access file I O where they can move to any location in the file without reading all the bytes between their current location and where they want to get to When they get there unless they have read further about random access I O they don t realize it is possible to overwrite one record on disk without disturbing the record before and after it And finally they have a hard time merging object oriented concepts which are only RAM related and file records Usual ly a programmer writes a class to have some kind of functions written to write a RAM instance to a file record and also provides a function to read from disk back into a RAM instance It is not student s fault that they do not understand these concepts Let s talk about the last topic above a class that provides instances that are also stored on disk What must such a class provide e Functions to create open and move around the file And constructors for RAM instances e A function static or instance to w
34. ternate design Give an alternate OCD dia gram which illustrates a different design from the one you are going to adopt but which actual ly could have been used Generally you will want to show the effect of a major design policy change Don t spend a lot of time using a computer to draw this you could just sketch it with a pencil Also don t give the individual scenarios just an overall OCD In a paragraph or two discuss the advantages and disadvantages of this alternate design when compared to the actual design you want to use Finally mention why you feel your final de Page 7 of 16 sign s advantages outweigh the alternate design s advantages or why your final design s disad vantages are fewer than the alternate s This is your chance to blow your own horn and tell me WHY your design is so CLEAN and beautiful architecturally not implementation or effi ciency wise but architecture wise 5 0 Initial Interface Design Justify the use of any exported constants types or variables Discuss why you couldn t avoid them or why they contribute to a more maintainable design 6 0 Detailed Interface Design State that detailed interface design is not part of this document and refer the reader to the main and header class modules included separately in the release 7 0 Suggestions for Lower Level Design Optional As a high level architect you may optionally include any advice for the lower level coders here T
35. tion Where will go below the function switch or loop or on the first line Will the body of the else clause be indented 3 or 5 spaces Will be surrounded by spaces and will there be spaces after commas and colons e g from Modula 2 Type Color Red Green Blue Page 9 of 16 vs Type Color Red Green Blue Document your coding convention at the end of the main module It should only take about a half page if you are concise Before group members set off to code they should agree on this convention write this half page of the main and give e mail each member a copy This will prevent some poor editor from having to go through all the code just before the assignment due date and fix it all up See my example format below and choose a similar convention to adopt in your group Your convention must include all the information my example does though you may format it differently if you want The only exceptions are the following compulsory things z n C each individual function prototype in header files must be immediately preceded with a thin horizontal dividing line You are not to put a line then comments then the function prototype body This is because when scanning a document the TAs and I and most programmers want to find the function signatures quickly not have to wade through a indefinite number of comments lines under a dividing line to find the signature Put any specific comments regardin
36. use it as the return value If you want to return several base types via the parameter list you must use special holder classes Java provides wrapper classes for base types so that you can put an integer in a linked list Java lists assume the elements in the list are references to object instances not int or float Java provides wrapper classes like Integer and Float which are instances that can hold an int or float respectively However these silly classes do not allow you to ever change the contained value Instead you have to import the classes IntHolder FloatHolder et cetera from the package org omg CORBA Here is an example import org omg CORBA int value 6 IntHolder myIntReference new IntHolder value y functionThatChangesValue myIntReference Java is a beautiful language but not everything about Java is beautiful eh The three not very beautiful things about Java that I hate are keyboard input binary I O of in stances and passing base types by reference as shown above Russ Tront Page 16 of 16
37. y code in a client module This information is included as comments within the in terface definition files I want you to realize that by defining the types of parameters used by procedures you are NOT defining how that parameter info is to be stored in a hidden data structure file encapsulated by the module boundary 1 e If a date is passed to a module as type String say an array of 8 char acters 91 02 25 this does NOT mean that it could not be converted inside the function and stored as three separate unsigned short integers or as a linked list of characters Realizing this will ease your mind when you feel you are going out on a limb by defining interfaces for which the internal representations are not yet determined Do not create interfaces that commit the im plementation module coders in Assignment 4 to a particular design Type definitions for the entities used in the interface are just that interface types not storage types Internals are not your problem as a high level designer so don t worry about it and especially don t let it distract clutter your mind Also keeping this in mind may help you as a coder later you don t have to store things with the same representation they are passed into a function So don t worry too much about how the interface will affect the implementation module code A large system may have 100s of modules and 1000s of procedures You can t worry about the implementation at this point Instea
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