How can you extend the Observer pattern to support observers that only want updates for specific types of changes?

hard📝 Trade-off Q9 of Q15

LLD - Behavioral Design Patterns — Part 1

AMake all observers receive all updates and filter internally

BUse multiple Subjects for each change type without filtering

CRemove observers frequently to control notifications

DAdd filtering logic in Subject to notify only relevant observers

Step-by-Step Solution

Solution:

Step 1: Understand selective notification need
Observers want updates only for certain change types.
Step 2: Implement filtering in Subject
Subject can track observer interests and notify selectively.
Final Answer:
Add filtering logic in Subject to notify only relevant observers -> Option D
Quick Check:
Selective notify requires filtering in Subject [OK]

Quick Trick: Filter notifications in Subject for selective updates [OK]

Common Mistakes:

MISTAKES

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