design-patterns/behavioral/strategy/context.py

from behavioral.strategy.strategy import Strategy


class Context:
    """
    The Context defines the interface of interest to clients.
    """

    def __init__(self, strategy: Strategy):
        """
        Usually, the Context accepts a strategy through the constructor, but also provides a setter to change it at
        runtime.
        """
        self._strategy = strategy

    @property
    def strategy(self):
        """
        The Context maintains a reference to one of the Strategy objects. The
        Context does not know the concrete class of a strategy. It should work
        with all strategies via the Strategy interface.
        """
        return self._strategy

    @strategy.setter
    def strategy(self, strategy: Strategy):
        """
        Usually, the Context allows replacing a Strategy object at runtime.
        """
        self._strategy = strategy

    def do_some_business_logic(self) -> None:
        """
        The Context delegates some work to the Strategy object instead of implementing multiple versions of the
        algorithm on its own.
        """

        print("Context: Sorting data using the strategy (not sure how it'll do it)")
        result = self._strategy.do_algorithm(["a", "b", "c", "d", "e"])
        print(",".join(result))