Strategy - Harsh4999/Design-Patterns GitHub Wiki

Strategy

USE

• Allows us to encapsulate an algo in class. Possible to use varios algo's
• A good indication to use this is when we have different condition for making a calculation for using different approaches
• Usually implemented in an inheritance hierarchy so that we can choose any one implementation and it'll work with our main object/context as the interface is same for all implementations.

UML

• Context: Uses strategy object to perform an operation. It will hold a strategy object inside which will have algo implementation
• Strategy: Interface defining different algo
• Concrete Strategy: Implementation of strategy

Implementation

• Start by creating interface for strategy. Context class provides strategy with all the data that it needs.
• We provide implementation for various algorithms by implementing strategy interface a class per algorithm
• Our context class provides a way to configure it with one of the strategy implementations.
• We can configure in such a way that if client does not give strategy we use default stratedy
• Eg: Comparator