34 lines
1.2 KiB
Markdown
34 lines
1.2 KiB
Markdown
---
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layout: pattern
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title: Event Aggregator
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folder: event-aggregator
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permalink: /patterns/event-aggregator/
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categories: Structural
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tags:
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- Reactive
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---
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## Intent
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A system with lots of objects can lead to complexities when a
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client wants to subscribe to events. The client has to find and register for
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each object individually, if each object has multiple events then each event
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requires a separate subscription. An Event Aggregator acts as a single source
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of events for many objects. It registers for all the events of the many objects
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allowing clients to register with just the aggregator.
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## Class diagram
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## Applicability
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Use the Event Aggregator pattern when
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* Event Aggregator is a good choice when you have lots of objects that are
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potential event sources. Rather than have the observer deal with registering
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with them all, you can centralize the registration logic to the Event
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Aggregator. As well as simplifying registration, a Event Aggregator also
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simplifies the memory management issues in using observers.
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## Credits
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* [Martin Fowler - Event Aggregator](http://martinfowler.com/eaaDev/EventAggregator.html)
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