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#
# libraryBookDemo.py
#
# Simple statemachine demo, based on the state transitions given in librarybookstate.pystate
#
import statemachine
import librarybookstate
class Book(librarybookstate.BookStateMixin):
def __init__(self):
self.initialize_state(librarybookstate.New)
class RestrictedBook(Book):
def __init__(self):
super().__init__()
self._authorized_users = []
def authorize(self, name):
self._authorized_users.append(name)
# specialized checkout to check permission of user first
def checkout(self, user=None):
if user in self._authorized_users:
super().checkout()
else:
raise Exception(
"{} could not check out restricted book".format(
user if user is not None else "anonymous"
)
)
def run_demo():
book = Book()
book.shelve()
print(book)
book.checkout()
print(book)
book.checkin()
print(book)
book.reserve()
print(book)
try:
book.checkout()
except librarybookstate.BookState.InvalidTransitionException as e:
print(e)
print("..cannot check out reserved book")
book.release()
print(book)
book.checkout()
print(book)
print()
restricted_book = RestrictedBook()
restricted_book.authorize("BOB")
restricted_book.restrict()
print(restricted_book)
for name in [None, "BILL", "BOB"]:
try:
restricted_book.checkout(name)
except Exception as e:
print(".." + str(e))
else:
print("checkout to", name)
print(restricted_book)
restricted_book.checkin()
print(restricted_book)
if __name__ == "__main__":
run_demo()