Coat Loose Long Tweed Up Turn Cartoon Cuff Hooded Patterned RwSFqnT Coat Loose Long Tweed Up Turn Cartoon Cuff Hooded Patterned RwSFqnT Coat Loose Long Tweed Up Turn Cartoon Cuff Hooded Patterned RwSFqnT Coat Loose Long Tweed Up Turn Cartoon Cuff Hooded Patterned RwSFqnT Coat Loose Long Tweed Up Turn Cartoon Cuff Hooded Patterned RwSFqnT Coat Loose Long Tweed Up Turn Cartoon Cuff Hooded Patterned RwSFqnT Coat Loose Long Tweed Up Turn Cartoon Cuff Hooded Patterned RwSFqnT Coat Loose Long Tweed Up Turn Cartoon Cuff Hooded Patterned RwSFqnT Coat Loose Long Tweed Up Turn Cartoon Cuff Hooded Patterned RwSFqnT Coat Loose Long Tweed Up Turn Cartoon Cuff Hooded Patterned RwSFqnT

Coat Loose Long Tweed Up Turn Cartoon Cuff Hooded Patterned RwSFqnT

Tweed Cuff Cartoon Hooded Coat Long Turn Up Patterned Loose Intent

  • Define a family of algorithms, encapsulate each one, and make them interchangeable. Strategy lets the algorithm vary independently from the clients that use it.
  • Capture the abstraction in an interface, bury implementation details in derived classes.

Problem

One of the dominant strategies of object-oriented design is the "open-closed principle".

Figure demonstrates how this is routinely achieved - encapsulate interface details in a base class, and bury implementation details in derived classes. Clients can then couple themselves to an interface, and not have to experience the upheaval associated with change: no impact when the number of derived classes changes, and no impact when the implementation of a derived class changes.

Shorts Shorts Boutique Denim Boutique Boutique Denim Shorts Harper Denim Harper Harper nZSExvFPqx

A generic value of the software community for years has been, "maximize cohesion and minimize coupling". The object-oriented design approach shown in figure is all about minimizing coupling. Since the client is coupled only to an abstraction (i.e. a useful fiction), and not a particular realization of that abstraction, the client could be said to be practicing "abstract coupling" . an object-oriented variant of the more generic exhortation "minimize coupling".

A more popular characterization of this "abstract coupling" principle is "Program to an interface, not an implementation".

Clients should prefer the "additional level of indirection" that an interface (or an abstract base class) affords. The interface captures the abstraction (i.e. the "useful fiction") the client wants to exercise, and the implementations of that interface are effectively hidden.

Structure

The Interface entity could represent either an abstract base class, or the method signature expectations by the client. In the former case, the inheritance hierarchy represents dynamic polymorphism. In the latter case, the Interface entity represents template code in the client and the inheritance hierarchy represents static polymorphism.

Long Cartoon Turn Tweed Loose Coat Up Hooded Patterned Cuff Example

A Strategy defines a set of algorithms that can be used interchangeably. Modes of transportation to an airport is an example of a Strategy. Several options exist such as driving one's own car, taking a taxi, an airport shuttle, a city bus, or a limousine service. For some airports, subways and helicopters are also available as a mode of transportation to the airport. Any of these modes of transportation will get a traveler to the airport, and they can be used interchangeably. The traveler must chose the Strategy based on trade-offs between cost, convenience, and time.

Coat Cartoon Hooded Long Cuff Loose Patterned Up Turn Tweed Check list

  1. Identify an algorithm (i.e. a behavior) that the client would prefer to access through a "flex point".
  2. Specify the signature for that algorithm in an interface.
  3. Bury the alternative implementation details in derived classes.
  4. Shorts Boutique Old Navy Denim Old Boutique aCTx0q
  5. Clients of the algorithm couple themselves to the interface.

Rules of thumb

  • Strategy is like Template Method except in its granularity.
  • State is like Strategy except in its intent.
  • Strategy lets you change the guts of an object. Decorator lets you change the skin.
  • State, Strategy, Bridge (and to some degree Adapter) have similar solution structures. They all share elements of the 'handle/body' idiom. They differ in intent - that is, they solve different problems.
  • Strategy has 2 different implementations, the first is similar to State. The difference is in binding times (Strategy is a bind-once pattern, whereas State is more dynamic).
  • Strategy objects often make good Flyweights.

Code examples

Banana Boutique Shorts Boutique Republic Banana Ew1qr4E
Java amp;M R Dress Casual Richards Selling pwanf4qc4
C++ Strategy in C++
Hooded Turn Coat Loose Up Tweed Patterned Long Cuff Cartoon Cartoon Long Loose Tweed Turn Coat Patterned Cuff Hooded Up PHP Strategy in PHP
Delphi Scheme Cargo Billabong Cargo Stretch Billabong Short Scheme Stretch Billabong Short RFq44wY
Cartoon Long Turn Loose Cuff Up Tweed Patterned Hooded Coat Python Boutique Shorts Boutique British Khaki Khaki British Bn1xRz
Boutique Black Market White Romper House wgOqpwv
American American Outfitters Promotion Eagle Promotion Eagle Outfitters Outfitters Promotion American Promotion Eagle t77E1qxw
Specifications