Today to see the part of the state machine, and can simplify the code book, then there is the following the old scheme and a new scheme, and then have the following 4 piece of confusion, a new scheme to tell the truth feeling like gobbledygook, a face of meng force completely, doesn't understand how to simplify the code on new package), each master can help explain the meaning of some related code, thank you very much

"" "the old scheme, a lot of a statement, inefficient "" "
The class Connection:
Def __init__ (self) :
The self. The state='CLOSED'
Def read (self) :
If the self state!='OPEN' :
Raise RuntimeError (' Not open ')
Print (' reading ')
Def write (self, data) :
If the self state!='OPEN' :
Raise RuntimeError (' Not open ')
Print (' writing ')
Def open (self) :
If self. State=='OPEN' :
Already raise RuntimeError (' open ')
The self. The state='OPEN'
Def close (self) :
If the self. The state=='CLOSED' :
Raise RuntimeError (' Already closed ')
The self. The state='CLOSED'


"" "the new scheme, for each state defines a class, class Connection1 is the "" "
The class Connection1:
Def __init__ (self) :
Self. New_state (ClosedConnectionState) doubt # 1 this code is what meaning, what new_state and ClosedConnectionState said
Def new_state (self, newstate because) : # wondering what is the purpose of this code 2
Self. _state=newstate because
Def read (self) :
# call is subordinate to the instance methods (Close/Open)
Return the self. _state. Read (self)
Def write (self, data) :
Return the self. _state. Write (self, data)
Def open (self) :
Return the self. _state. Open (self)
Def close (self) :
Return the self. _state. Close (self)


Class ConnectionState: # doubt 3 actually this whole class ConnectionState: don't understand meaning
@ # staticmethod wondering what part 4 staticmethod is corresponding to the above
Def read (conn) :
# subclasses must implement methods of the parent, or report the following error
Raise NotImplementedError ()
@ staticmethod
Def write (conn, data) :
Raise NotImplementedError ()
@ staticmethod
Def open (conn) :
Raise NotImplementedError ()
@ staticmethod
Def close (conn) :
Raise NotImplementedError ()


Class ClosedConnectionState (ConnectionState) : # doubts this is associated with the above ClosedConnectionState?
@ staticmethod
Def read (conn) :
Raise RuntimeError (' Not open ')
@ staticmethod
Def write (conn, data) :
Raise RuntimeError (' Not open ')
@ staticmethod
Def open (conn) :
Conn. New_state (OpenConnectionState)
@ staticmethod
Def close (conn) :
Raise RuntimeError (' Already closed ')


The class OpenConnectionState (ConnectionState) :
@ staticmethod
Def read (conn) :
Print (' reading ')
@ staticmethod
Def write (conn, data) :
Print (' writing ')
@ staticmethod
Def open (conn) :
Already raise RuntimeError (' open ')
@ staticmethod
Def close (conn) :
# into the Close instance, call the superclass method new_state
Conn. New_state (ClosedConnectionState)

CodePudding user response:

Can see my blog, auxiliary understanding

CodePudding user response:

https://blog.csdn.net/hbu_pig/article/details/80808896

CodePudding user response:

You this is a lot of the object-oriented basic knowledge of grammar can't see, just looking at the program
Advice first take a look at class, inheritance, class of static methods and class methods and instance methods
Everything python objects