87 lines
2.6 KiB
Python
87 lines
2.6 KiB
Python
from collections import OrderedDict
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from .Node import Node
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def isNodeClass(cls):
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try:
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if not issubclass(cls, Node):
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return False
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except:
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return False
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return hasattr(cls, 'nodeName')
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class NodeLibrary:
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"""
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A library of flowchart Node types. Custom libraries may be built to provide
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each flowchart with a specific set of allowed Node types.
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"""
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def __init__(self):
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self.nodeList = OrderedDict()
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self.nodeTree = OrderedDict()
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def addNodeType(self, nodeClass, paths, override=False):
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"""
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Register a new node type. If the type's name is already in use,
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an exception will be raised (unless override=True).
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============== =========================================================
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**Arguments:**
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nodeClass a subclass of Node (must have typ.nodeName)
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paths list of tuples specifying the location(s) this
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type will appear in the library tree.
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override if True, overwrite any class having the same name
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============== =========================================================
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"""
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if not isNodeClass(nodeClass):
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raise Exception("Object %s is not a Node subclass" % str(nodeClass))
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name = nodeClass.nodeName
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if not override and name in self.nodeList:
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raise Exception("Node type name '%s' is already registered." % name)
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self.nodeList[name] = nodeClass
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for path in paths:
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root = self.nodeTree
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for n in path:
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if n not in root:
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root[n] = OrderedDict()
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root = root[n]
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root[name] = nodeClass
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def getNodeType(self, name):
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try:
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return self.nodeList[name]
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except KeyError:
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raise Exception("No node type called '%s'" % name)
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def getNodeTree(self):
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return self.nodeTree
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def copy(self):
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"""
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Return a copy of this library.
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"""
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lib = NodeLibrary()
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lib.nodeList = self.nodeList.copy()
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lib.nodeTree = self.treeCopy(self.nodeTree)
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return lib
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@staticmethod
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def treeCopy(tree):
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copy = OrderedDict()
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for k,v in tree.items():
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if isNodeClass(v):
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copy[k] = v
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else:
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copy[k] = NodeLibrary.treeCopy(v)
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return copy
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def reload(self):
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"""
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Reload Node classes in this library.
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"""
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raise NotImplementedError()
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