Implementation Issues

• Implementation Variants
  • The Context and Strategy interfaces must be designed carefully so that the needed data can be passed/accessed efficiently and new algorithms can be added without having to extend an interface. There are two main variants:
• Variant1: Push Data
  • Context passes the data to the strategy:
    strategy.algorithm(data1,data2,…)
  • The Strategy interface may get complex because it must pass in the needed data for all supported algorithms (whether they are simple or complex).
• Variant2: Pull Data
  • Context passes nothing but itself to the strategy, letting strategy call back to get (pull) the required data from context:
    strategy.algorithm(this)
  • The Context interface may have to be extended to let strategies do their work and access the needed data.