randomaccessfile quick start
TRANSCRIPT
2+Agenda
RandomAccessFile overview
Implement CRUD functions by RandomAccessFile Use case diagram Sequence diagram Class diagram classes
3+What is RandomAccessFile?
A random access file behaves like a large array of bytes stored in the file system. There is a kind of cursor, or index into the implied array, called the file pointer; input operations read bytes starting at the file pointer and advance the file pointer past the bytes read.
Random-access files are solution Instant access Insert record without destroying other data Update/delete items without changing other data
4+What is RandomAccessFile?
imposes no structure on files Programmer must create random-access files Simplest way: fixed-length records
Calculate position in file from record size and key
5+Use Case Diagram
6+Class Diagram
7+DVD.java
Be made up of a couple of setter and getter methods
Defined length for each column
A DVD record
8+
9+DVDClient.java
Play the role of client to do CRUD C (Create): addDVD() R (Read): findAll() and findByCriteria() U (Update): modifyDVD() D (Delete): deleteDVD
10+DvdFileAccess.java
All random access file-related codes are in this class
11+findAll()
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Retrieve DVD data based on the cursor
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findByCriteria()
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findByCriteria() – cont.
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persistDvd()
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modifyDVD()
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deleteDVD()
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