Design Patterns · The Observer Pattern provides an object design where subjects and observers are...
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Transcript of Design Patterns · The Observer Pattern provides an object design where subjects and observers are...
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Observer Pattern
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Weather Information machine
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Code look
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Lets implement
Concrete Class
Same update
Varies
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Observer Concept
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Observer Class Definition
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Power of loose couple
• The subject doesn’t know anything about the implementation except the interface they implement.
• Add new observers anytime.
• Minimum change if we added new observers.
• Change in observer or subject will never change in each other.
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Weather Information new design
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Code for subject
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Code for Observer
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Main Program