Python Adapter Class: Wrap Legacy Interface

class LegacySystem:
    """Legacy interface - old method names and parameter format."""
    def query_employee_info(self, emp_id, emp_name):
        return f"Legacy: {emp_id} - {emp_name}"

    def update_employee_department(self, emp_id, department_code):
        return f"Legacy: Updated {emp_id} to dept {department_code}"

class EmployeeAdapter:
    """Adapter to expose a modern interface over LegacySystem."""
    def __init__(self, legacy_system):
        self._legacy = legacy_system

    def get_employee(self, employee_id):
        # New interface takes just ID; adapter provides a default name
        return self._legacy.query_employee_info(employee_id, "Unknown")

    def set_employee_department(self, employee_id, department_name):
        # Map friendly department name to legacy numeric code
        dept_codes = {"Engineering": 101, "Sales": 202, "HR": 303}
        code = dept_codes.get(department_name, 000)
        return self._legacy.update_employee_department(employee_id, code)

if __name__ == "__main__":
    legacy = LegacySystem()
    adapter = EmployeeAdapter(legacy)

    print(adapter.get_employee(12345))
    print(adapter.set_employee_department(12345, "Engineering"))