Strategy Pattern

defines a family of algorithms, encapsulates each one, and makes them interchangeable.Strategy lets the algorithm vary independently from clients that use it.

Class A{
SortInterface i;
}

Interface SortInterface{
sort();
}

Class ConcreteAlgorithm1 implements SortInterface{
sort(){
...
}

}

Class ConcreteAlgorithm2 implements SortInterface{
sort(){
...
}

}

a family of sort algorithms