Free  Understanding Design Patterns - Strategy

Defines a family of algorithms, encapsulates each one, and makes them interchangeable. Strategy lets the algorithm vary independently from clients that use it. Commuting is a part of our daily lives. Every day, when ...

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Free  Understanding Design Patterns - Template Method

Defines the skeleton of an algorithm in a method, deferring some steps to subclasses. Template Method lets subclasses redefine certain steps of an algorithm without changing the algorithm’s structure. ...

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Free  Understanding Design Patterns - Command

Encapsulates a request as an object, thereby letting you parameterize other objects with different requests, queue or log requests, and support undoable operations. Battles are meant to be won, and no battle can be w...

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Free  Understanding Design Patterns - Observer

Defines a one-to-many dependency between objects so that when on object changes state, all of its dependents are notified and updated automatically. Mary just became a new Mom! Like all new mothers, she is very excit...

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Free  Understanding Design Patterns - Singleton

Ensures a class has only one instance, and provides a global point of access of it. The health clinic has recently offered free medicines if you come in for a checkup. The promotional stint is wo...

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