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In some programming languages, such as those without polymorphism, the issues addressed by strategy pattern are handled through forms of reflection, such as the native function pointer or function delegate syntax. | In some programming languages, such as those without polymorphism, the issues addressed by strategy pattern are handled through forms of reflection, such as the native function pointer or function delegate syntax. | ||
= Example & Illustration = | = Example & Illustration = | ||
[[Image:Strategy-Example.jpg]] | |||
= Real World Problem = | = Real World Problem = | ||
== Java's Solution == | == Java's Solution == | ||
Revision as of 23:22, 28 September 2007
Note: Santthosh (sbselvad@ncsu.edu) and Agustin (agusvega@nc.rr.com) are editing this page.
Strategy Pattern
Strategy pattern is one of the several software design patterns, where in algorithms can be selected on-the-fly at runtime execution of the program. The Strategy pattern lets one build software as a loosely coupled collection of interchangeable parts, in contrast to a monolithic, tightly coupled system. That loose coupling makes the software much more extensible, maintainable, and reusable. The strategy pattern is useful for situations where it is necessary to dynamically swap the algorithms used in an application.
Concept to explore
Take a case of the Strategy pattern and implement it as succinctly as possible in Ruby and Java. Compare the two implementations in terms of clarity and succinctness. The example should be a "real-world" example. While it may be grossly oversimplified for the purpose of illustration, it should not be totally contrived (i.e., should not raise the question, Why would anyone ever want to do that?).
Definitions
Design Patterns
A design pattern is a general repeatable solution to a commonly occurring problem in software design. A design pattern is neither a finished design nor a solution that can be transformed directly into code. It is a template on how to solve a problem that can be used in many different situations. Design patterns are more often use in Object oriented designs as they typically show relationships and interactions between classes or objects, without specifying the final application classes or objects that are involved.
Note: Algorithms are not design patterns, algorithms solve computational problems and design patterns solve design problems.
Strategy Pattern
The Strategy Design Pattern defines a family of algorithms, encapsulates each one, and makes them interchangeagle. Stratergy lets the algorithm vary independently from clients that use it.
Polymorphism
Encapsulation
Composition
Inheritance
Related Patterns
Alternatives
In some programming languages, such as those without polymorphism, the issues addressed by strategy pattern are handled through forms of reflection, such as the native function pointer or function delegate syntax.
Example & Illustration
