Strategy

Intent

Define a family of algorithms, encapsulate each one, and make them interchangeable. Strategy lets the algorithm vary independently from clients that use it.

Class diagram of the original GoF pattern

Another solution in MixJuice

Solved Problem(s)

Complexity problem

The class structure of the original GoF pattern is complicated. (This problem is not mentioned in the GoF book.)

Used programming technique(s)

Implementation selection for Context.

Consequences

• (+) Class structure is not complicated.
• (-) This solution is applicable only if just one implementation of the Algorithm method is used in a program.

Structure and pseudo code

module m {
  define class C {
    define void contextInterface() {
      ... algorithmInterface() ...
    }
    define abstract void algorithmInterface();
  }
}
module m.strategyA extends m {
  class C { void algorithmInterface() {...} }
}
module m.strategyB extends m {
  class C { void algorithmInterface() {...} }
}

Top