Design Pattern DESIGNP

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Design Pattern

OutlineWhat is ?

Why Design Pattern?Pattern In ActionObserver PatternSingleTon PatternClassificationFeedback

Design Pattern

What is DP

General *Reusable* solution to Commonly Occurring problem(Experience Reuse Rather Code Reuse)

Description or Template for how to

Solve A *Common Problem*

Design Pattern

Learn DP

There are around 50(!)s of DPs Already done for you.

So, We Won’t **REINVENT THE WHEEL**

Design Pattern

DP

There are around 50(!)s of DPs Already done for you.

So, We Won’t **REINVENT THE WHEEL**

Design Pattern

Pattern In action

Google Alert / RSS Feed

What Happens?

Design Pattern

Pattern In action

Google Alert / RSS Feed

What Happens?1. New user can subscribe any time

Design Pattern

Pattern In action

Google Alert / RSS Feed

What Happens?1.New user can subscribe any time2.Existing user can De subscribe

Design Pattern

Pattern In action

Google Alert / RSS Feed

What Happens?1.New user can subscribe any time2.Existing user can Desubscribe

Design Pattern

Pattern In action

Google Alert / RSS Feed

What Happens?1.New user can subscribe any time2.Existing user can Desubscribe

Design Pattern

Pattern In action

Google Alert / RSS Feed

What Happens?1.New user can subscribe any time2.Existing user can Desubscribe3.When any updates (Google) automatically Flood this to all subcribers

Design Pattern

Pattern In action

Google Alert / RSS Feed

What Happens?1.New user can subscribe any time2.Existing user can Desubscribe3.When any updates (Google) automatically Flood this to all subcribers

Design Pattern

Pattern In action

Solution is The OBSERVER PATTERN