Authors:
Umangkumar Maheshbhai Patel - 40228475
Raveena Choudhary - 40232370

Assignment 3- APP

Observer pattern is used as a base application to write aspectj definition named as "Instrumentator.aj"

"Instrumentator.aj" covers method used in base application such as:

1. To add an observer: addObserver(Observer observer)
2. To notify observers: notifyObservers()
3. To update an observer: update()
4. To remove an observer: removeObserver(Observer observer)
5. To get headLine from Blogger: getHeadline()
6. To get current state from Observer: getState()

Also, a file "callgraph.dot" has been created through program(Please refer Logger.java) - to generate UML(Sequence Diagram) using a tool dotUML(https://dotuml.com/playground.html#).

DOT graphical language is as below:

/*
 * Description: This is an automatically generated .DOT file
 * representing a call graph.
 * Author: Umangkumar Maheshbhai Patel - 40228475, Raveena Choudhary - 40232370
 * Date: Sun Oct 30 15:05:35 EDT 2022
 *
 */
SequenceDiagram [frame=true framecolor=steelblue label="Observer Design PatternSequence Diagram"]{
 lifeline "Blogger:blogger" as Blogger
 lifeline "Newsportal:observer 1" as Newsportal
 Newsportal --> Blogger "1. addObserver(..)"
 lifeline "Newspaper:observer 2" as Newspaper
 Newspaper --> Blogger "2. addObserver(..)"
 lifeline "MobileSubscriber:observer 3" as MobileSubscriber
 MobileSubscriber --> Blogger "3. addObserver(..)"
 -f-> Blogger "4. setHeadline(..)"
 Blogger --> Blogger "5. notifyObservers()"
 Blogger --> Newsportal "6. update()"
 Newsportal --> Blogger "7. getHeadline()"
 Blogger --> Newspaper "8. update()"
 Newspaper --> Blogger "9. getHeadline()"
 Blogger --> MobileSubscriber "10. update()"
 MobileSubscriber --> Blogger "11. getHeadline()"
 Newsportal --> Newsportal "12. getState()"
 Newspaper --> Newspaper "13. getState()"
 MobileSubscriber --> MobileSubscriber "14. getState()"
 Blogger --> Blogger "15. removeObserver(..)"
 -f-> Blogger "16. setHeadline(..)"
 Blogger --> Blogger "17. notifyObservers()"
 Blogger --> Newsportal "18. update()"
 Newsportal --> Blogger "19. getHeadline()"
 Blogger --> Newspaper "20. update()"
 Newspaper --> Blogger "21. getHeadline()"
 Newsportal --> Newsportal "22. getState()"
 Newspaper --> Newspaper "23. getState()"
 MobileSubscriber --> MobileSubscriber "24. getState()"
}