wxPython/samples/ide/activegrid/util/dependencymgr.py

   1 #----------------------------------------------------------------------------
   2 # Name:         dependencymgr.py
   3 # Purpose:      Dependency Manager
   4 #
   5 # Author:       Jeff Norton
   6 #
   7 # Created:      01/28/05
   8 # CVS-ID:       $Id$
   9 # Copyright:    (c) 2004-2005 ActiveGrid, Inc.
  10 #----------------------------------------------------------------------------
  11
  12 DM_NO_ID = 0
  13 DM_ID_ATTR = "_DependencyMgr__ID"
  14
  15 ##class ManageableObject(object):
  16 ##
  17 ##    def __init__(self):
  18 ##        self.__id = DM_NO_ID
  19 ##
  20 ##    def __repr__(self):
  21 ##        return "<ManageableObject id = %s>" % self.__id
  22 ##
  23 ##    def __getID(self):
  24 ##        return self.__id
  25 ##
  26 ##    def __setID(self, value):
  27 ##        if (self.__id != DM_NO_ID):
  28 ##            raise DependencyMgrException("Cannot set the dependency ID on object %s to \"%s\" because it already has one (\"%s\")." % (repr(self), value, self.__id))
  29 ##        self.__id = value
  30 ##
  31 ##    _DependencyMgr__ID = property(__getID, __setID)
  32
  33 class DependencyMgr(object):
  34
  35     def __init__(self):
  36         self.clear()
  37
  38     def clear(self):
  39         self.__dependencies = {}
  40         self.__lastID = DM_NO_ID
  41
  42     def addDependency(self, parent, child):
  43         pid = self._initObjectID(parent)
  44         try:
  45             parentCollection = self.__dependencies[pid]
  46         except KeyError:
  47             parentCollection = self._newDependencyCollection()
  48             self.__dependencies[pid] = parentCollection
  49         if (child not in parentCollection):
  50             parentCollection.append(child)
  51
  52     def removeDependency(self, parent, child):
  53         pid = self._getObjectID(parent)
  54         if (pid != DM_NO_ID):
  55             try:
  56                 parentCollection = self.__dependencies[pid]
  57                 parentCollection.remove(child)
  58                 if (len(parentCollection) == 0):
  59                     del self.__dependencies[pid]
  60             except KeyError, ValueError:
  61                 pass
  62
  63     def clearDependencies(self, parent):
  64         "Returns a list of objects or an empty list if no dependencies exist as for getDependencies, and then removes the dependency list."
  65         pid = self._getObjectID(parent)
  66         try:
  67             deps = self.__dependencies[pid]
  68             del self.__dependencies[pid]
  69             return deps
  70         except KeyError:
  71             return []
  72
  73     def hasDependency(self, parent):
  74         "Returns a boolean"
  75         return (self._getObjectID(parent) in self.__dependencies)
  76
  77     def getDependencies(self, parent):
  78         "Returns a list of objects or an empty list if no dependencies exist."
  79         try:
  80             return self.__dependencies[self._getObjectID(parent)]
  81         except KeyError:
  82             return []
  83
  84     def dumpState(self, out):
  85         "Writes the state of the dependency manager (as reported by getState) to out"
  86         for line in self.getState():
  87             print >> out, line
  88
  89     def getState(self):
  90         "Returns the state of the dependency manager including all managed objects as a list of strings"
  91         out = []
  92         out.append("DependencyMgr %s has %i parent objects, last id assigned is %i" % (repr(self), len(self.__dependencies), self.__lastID))
  93         for key, val in self.__dependencies.iteritems():
  94             out.append("Object %s has dependents: %s " % (repr(key), ", ".join([repr(d) for d in val])))
  95         return out
  96
  97     def _initObjectID(self, obj):
  98         try:
  99             id = getattr(obj, DM_ID_ATTR)
 100         except AttributeError:
 101             id = DM_NO_ID
 102         if (id == DM_NO_ID):
 103             id = self._newID()
 104             setattr(obj, DM_ID_ATTR, id)
 105         return id
 106
 107     def _getObjectID(self, obj):
 108         try:
 109             id = getattr(obj, DM_ID_ATTR)
 110         except AttributeError:
 111             id = DM_NO_ID
 112         return id
 113
 114     def _newID(self):
 115         self.__lastID += 1
 116         return self.__lastID
 117
 118     def _newDependencyCollection(self):
 119         return []
 120
 121 globalDM = DependencyMgr()
 122
 123 def addDependency(parent, child):
 124     getGlobalDM().addDependency(parent, child)
 125
 126 def removeDependency(parent, child):
 127     getGlobalDM().removeDependency(parent, child)
 128
 129 def clearDependencies(parent):
 130     return getGlobalDM().clearDependencies(parent)
 131
 132 def hasDependency(parent):
 133     return getGlobalDM().hasDependency(parent)
 134
 135 def getDependencies(parent):
 136     return getGlobalDM().getDependencies(parent)
 137
 138 def getState():
 139     return getGlobalDM().getState()
 140
 141 def dumpState(out):
 142     getGlobalDM().dumpState(out)
 143
 144 def getGlobalDM():
 145     return globalDM