STRATEGYSTRATEGYObject Behavioral Pattern

You are at the Pub two weeks before Fall You are at the Pub two weeks before Fall Formal and still don’t have a date! All of a Formal and still don’t have a date! All of a sudden a girl who you had a crush on during sudden a girl who you had a crush on during o-week walks ino-week walks in

There are many different ways that you could approach this situation. Each approach requires a different methodology, but achieves the same goal (i.e. you have confronted your crush)

How you doin?How you doin?

Do you believe in love at first sight or should I walk around the room again?

Intent of StrategyIntent of Strategy

• Define a family of algorithms, Define a family of algorithms, encapsulate each one, and make encapsulate each one, and make them interchangeablethem interchangeable

• Strategy provides a common Strategy provides a common interface for all encapsulated interface for all encapsulated algorithms and allows the algorithm algorithms and allows the algorithm to vary independently of the clientto vary independently of the client

When is Strategy used?When is Strategy used?

• When many related classes differ When many related classes differ only in their behavioronly in their behavior

• Different variants of an algorithm Different variants of an algorithm exist in order to reflect different exist in order to reflect different space/time trade-offsspace/time trade-offs

StructureStructure

Airline Ticket ReservationsAirline Ticket Reservations

• There are many different ways to There are many different ways to obtain an airline ticket. Depending obtain an airline ticket. Depending on your utility for time and money, on your utility for time and money, you may be looking for the cheapest you may be looking for the cheapest flight available or you might want to flight available or you might want to find the quickest flight to your find the quickest flight to your destination. destination.

Airline Ticket ReservationsAirline Ticket Reservations