Free  Understanding Design Patterns - Composite

Allows you to compose objects into tree structures to represent part-whole hierarchies. Composite lets clients treat individual objects and compositions of objects uniformly. Agnes has been working at Walmart for mor...

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Free  Understanding Design Patterns - Iterator

Provides a way to access the elements of an aggregate object sequentially without exposing its underlying representation. As a store manager, Eric’s job includes checking in products from each department. ...

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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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