Guvenc Gulce

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since May 19, 2004
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Recent posts by Guvenc Gulce

Tebrikler Serkan

Would you please tell us a bit more regarding the locking mechanism
that you have used ? this part seems to be the most bothering part
in the assignment. did you implement create()/delete() methods ?

Great Score !

Guvenc Gulce
Congrutalations Hugh,
Great Score.. !
I was just curious about the create()/delete() methods
of data class.. did you implement them, although your
clients dont use them ? or did you just throw
"Unsupportedexception" like some other guys did..

Regards

Guvenc Gulce
19 years ago
Merhaba Baris,
Here is a snip from sun faq:


What do I do if I fail the assignment?
If you have failed and wish to resubmit for another attempt, you will need to contact your local Sun office to purchase a resubmission voucher for your exam. You will only need to resubmit your assignment. We do not require you to retake your essay exam.



You can read it also here :



Sun Certification Faq

Regards

Guvenc Gulce
I agree with Steve.. no need for lock during read..
You are getting a snapshot view when you do a search. It is possible that after you have shown your search results(even with complicated locks for each read) in the GUI, some other clients may change the records afterwards and your snapshot view will become invalid anyway..
that is why(during update) you need to lock, re-read the record and if there is no change then update the record (finally unlock)
so your client will not trust the info that it has from the search results and it will double-check it ;-) should work.. ? I guess..

my 0.02 $ :-)

Guvenc
Hi All,

I am currently implementing my Data class (B&S) and I would like to have
some ideas from you guys regarding my approach..

-> My Data class is a singleton and has a static RAF and a static Record List (which gets opened in the constructor)

-> In the constructor of data class I read the whole file contents to memory(Record List) and do all the job in memory.(Search, Update, Read)

-> I am not sure when to flush memory contents(Record List) to the file. One idea would be to touch also the file together with memory during update,create,delete ???

-> I have created a class called GenericColumn (which has length(in bytes) and name of each available column from file's metadata information)

-> and I also have a Contractor class which get's an array of GenericColumn as a parameter in its constructor. (so it will have an idea about the column names and lengths) so I try not to hardcode any column info. In case a new column gets added to metadata. It will do the job without any change.

What you guys think about this approach ? do you see any obvious flaws in the design ? and also when to flush memory to the file ? (not using nio memory mapper and doing it by myself would be a good idea? as it says I should always use available APIs from the Java 2 but memorymapper is platform specific maybe I can justify my choice

Thanks for your inputs

Guvenc Gulce
Hi All
My name is Guvenc and I am on my way to SCJD so
I may bother you guys with some questions in the
following days/weeks.. :-)

Here are some questions :
-> Does SCJD have some expiration period like SCJP.
My SCJP will expire in 5 months. Does that mean I can
not take SCJD anymore and I have to take SCJP once more ?
Why expiration date ? Does the java language change
drasticly every two year ?

-> I want to keep the things simple during my implementation
and just want to do the things that are really necesssary (must)
I saw during browsing in the forum that more than one people
actually managed to get SCJD without implementing create / delete
methods. They are not used anywhere and there is nothing in
the assigment that implies that these methods need to be implemented.
But I still see in some posts that it is still being strongly adviced
to implement them by some guys in this forum. Why ?
Why should I implement them, if I can pass it withoud doing so
and when I have examples(guys passed without implementing) in
front of me ? (see this post)


2. The instructions in the document tell you what specific piece of funtionality you need to implement for your assignment. Mostly it would be booking() and searching() for a set of records. This is the functionality that is provider to the end-user using the application, but
the instructions also require us to implement all the functionality create, delete, update, read, find etc in the Data Access Layer ....The end-user of the application may not use all this functionality, but we have to implement them. Maybe client programs developed in the future could use this functionality on the server side.



Thanks for your help and here is a great forum
to gather information regarding SCJD

Guvenc Gulce