1. RandomAccessFile Quick Start Albert Guo junyuo@gmail.com 1

2. Agenda RandomAccessFile overview Implement CRUD functions by RandomAccessFile Use case diagram Sequence diagram Class diagram classes 2

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 3

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 4

5. Use Case Diagram 5

6. Class Diagram 6

7. DVD.java Be made up of a couple of setter and getter methods Defined length for each column 7 A DVD record

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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 9

10. DvdFileAccess.java All random access file-related codes are in this class 10

11. findAll() 11

12. 12 Retrieve DVD data based on the cursor

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15. findByCriteria() 15

16. findByCriteria() – cont. 16

17. persistDvd() 17

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20. modifyDVD() 20

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23. deleteDVD() 23

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