[PDF] Introduction to Design Patterns - University of Colorado

What is the observers design pattern?

Observer: Encapsulating Control Flow Name: Observer design pattern Problem description: Maintains consistency across state of one Subject and many Observers. Solution: A Subject has a primary function to maintain some state (e.g., a data structure).

What is observer pattern in AngularJS?

The Observer object is an abstract class that allows for the concrete observers to implements the notify method. Let’s take a look at an AngularJS example that encompasses the observer pattern through event management. With the observer pattern, it is important to distinguish the independent object or the subject.

What is the difference between observer and prototype?

• Observer:Define a one-to-many dependency between objects so that when one object changes state, all it‘s dependents are notified and updated automatically. • Prototype: • Specify the kinds of objects to create using a prototypical instance, and create new objects by copying this prototype.

What is the difference between observer pattern and polling pattern?

Observer pattern: Process A sends a message to process B that says "each time an event E occurs, send a message to Process A". Polling pattern: Process A regularly sends a message to process B that says "if you event E occured since the last time I've polled, send me a message now". The polling pattern produces a bit more network load.