statemap.py
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00001 #
00002 # The contents of this file are subject to the Mozilla Public
00003 # License Version 1.1 (the "License"); you may not use this file
00004 # except in compliance with the License. You may obtain a copy of
00005 # the License at http://www.mozilla.org/MPL/
00006 #
00007 # Software distributed under the License is distributed on an "AS
00008 # IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
00009 # implied. See the License for the specific language governing
00010 # rights and limitations under the License.
00011 #
00012 # The Original Code is State Machine Compiler (SMC).
00013 #
00014 # The Initial Developer of the Original Code is Charles W. Rapp.
00015 # Portions created by Charles W. Rapp are
00016 # Copyright (C) 2005. Charles W. Rapp.
00017 # All Rights Reserved.
00018 #
00019 # Port to Python by Francois Perrad, francois.perrad@gadz.org
00020 # Copyright 2004, Francois Perrad.
00021 # All Rights Reserved.
00022 #
00023 # Contributor(s):
00024 #
00025 # RCS ID
00026 # $Id: statemap.py,v 1.7 2009/11/24 20:42:39 cwrapp Exp $
00027 #
00028 # See: http://smc.sourceforge.net/
00029 #
00030 
00031 import sys
00032 
00033 class StateUndefinedException(Exception):
00034         """A StateUndefinedException is thrown by
00035         an SMC-generated state machine whenever a transition is taken
00036         and there is no state currently set. This occurs when a
00037         transition is issued from within a transition action."""
00038         pass
00039 
00040 class TransitionUndefinedException(Exception):
00041         """A TransitionUndefinedException is thrown by
00042         an SMC-generated state machine whenever a transition is taken
00043         which:
00044 
00045          - Is not explicitly defined in the current state.
00046          - Is not explicitly defined in the current FSM's default state.
00047          - There is no Default transition in the current state."""
00048         pass
00049 
00050 
00051 class State(object):
00052         """base State class"""
00053 
00054         def __init__(self, name, id):
00055                 self._name = name
00056                 self._id = id
00057 
00058         def getName(self):
00059                 """Returns the state's printable name."""
00060                 return self._name
00061 
00062         def getId(self):
00063                 """Returns the state's unique identifier."""
00064                 return self._id
00065 
00066 
00067 class FSMContext(object):
00068         """The user can derive FSM contexts from this class and interface
00069         to them with the methods of this class.
00070 
00071         The finite state machine needs to be initialized to the starting
00072         state of the FSM.  This must be done manually in the constructor
00073         of the derived class.
00074         """
00075 
00076         def __init__(self, state):
00077                 self._state = state
00078                 self._previous_state = None
00079                 self._state_stack = []
00080                 self._transition = None
00081                 self._debug_flag = False
00082                 self._debug_stream = sys.stderr
00083 
00084         def getDebugFlag(self):
00085                 """Returns the debug flag's current setting."""
00086                 return self._debug_flag
00087 
00088         def setDebugFlag(self, flag):
00089                 """Sets the debug flag.
00090                 A true value means debugging is on and false means off."""
00091                 self._debug_flag = flag
00092 
00093         def getDebugStream(self):
00094                 """Returns the stream to which debug output is written."""
00095                 return self._debug_stream
00096 
00097         def setDebugStream(self, stream):
00098                 """Sets the debug output stream."""
00099                 self._debug_stream = stream
00100 
00101         def getState(self):
00102                 """Returns the current state."""
00103                 if self._state == None:
00104                         raise StateUndefinedException
00105                 return self._state
00106 
00107         def isInTransition(self):
00108                 """Is this state machine already inside a transition?
00109                 True if state is undefined."""
00110                 if self._state == None:
00111                         return True
00112                 else:
00113                         return False
00114 
00115         def getTransition(self):
00116                 """Returns the current transition's name.
00117                 Used only for debugging purposes."""
00118                 return self._transition
00119 
00120         def clearState(self):
00121                 """Clears the current state."""
00122                 self._previous_state = self._state
00123                 self._state = None
00124 
00125 
00126         def getPreviousState(self):
00127                 """Returns the state which a transition left.
00128                 May be None"""
00129                 return self._previous_state
00130 
00131 
00132         def setState(self, state):
00133                 """Sets the current state to the specified state."""
00134                 if not isinstance(state, State):
00135                         raise ValueError("state should be a statemap.State")
00136                 self._state = state
00137                 if self._debug_flag:
00138                         self._debug_stream.write("NEW STATE       : %s\n" % self._state.getName())
00139 
00140         def isStateStackEmpty(self):
00141                 """Returns True if the state stack is empty and False otherwise."""
00142                 return len(self._state_stack) == 0
00143 
00144         def getStateStackDepth(self):
00145                 """Returns the state stack's depth."""
00146                 return len(self._state_stack)
00147 
00148         def pushState(self, state):
00149                 """Push the current state on top of the state stack
00150                 and make the specified state the current state."""
00151                 if not isinstance(state, State):
00152                         raise ValueError("state should be a statemap.State")
00153                 if self._state != None:
00154                         self._state_stack.append(self._state)
00155                 self._state = state
00156                 if self._debug_flag:
00157                         self._debug_stream.write("PUSH TO STATE   : %s\n" % self._state.getName())
00158 
00159         def popState(self):
00160                 """Make the state on top of the state stack the current state."""
00161                 if len(self._state_stack) == 0:
00162                         if self._debug_flag:
00163                                 self._debug_stream.write("POPPING ON EMPTY STATE STACK.\n")
00164                         raise ValueError("empty state stack")
00165                 else:
00166                         self._state = self._state_stack.pop()
00167                         if self._debug_flag:
00168                                 self._debug_stream.write("POP TO STATE    : %s\n" % self._state.getName())
00169 
00170         def emptyStateStack(self):
00171                 """Remove all states from the state stack."""
00172                 self._state_stack = []


smclib
Author(s): Various
autogenerated on Sun Oct 5 2014 22:32:28