Taken "class name to python class" code from convertNodesToPythonClass and created convertStringToPythonClass.

So that code can be factorized.

src/core/stations.py

@@ -249,20 +249,12 @@ class AbstractStation(object):
                 raise KeyError(xpath)
             return default
         classPath = nodes[0].content.strip()
-        i = classPath.rfind(".")
-        assert i >= 0
-        modulePath = classPath[:i]
-        component = __import__(modulePath)
-        componentNames = classPath.split(".")
-        try:
-            for componentName in componentNames[1:]:
-                component = getattr(component, componentName)
-        except AttributeError:
-            logs.info('Unknown Python class = "%s"' % classPath)
+        clas = self.convertStringToPythonClass(classPath)
+        if clas is None:
             if default == "none":
                 raise KeyError(xpath)
             return default
-        return component
+        return clas
 
     def convertNodesToString(self, nodes, nodesOwner, xpath, default = "none"):
         if not nodes:
@@ -305,6 +297,22 @@ class AbstractStation(object):
         else:
             return self.convertPathToAbsolute(location)
 
+    def convertStringToPythonClass(self, classPath):
+        """ Returns the Python class named in classPath.
+        """
+        i = classPath.rfind(".")
+        assert i >= 0
+        modulePath = classPath[:i]
+        component = __import__(modulePath)
+        componentNames = classPath.split(".")
+        try:
+            for componentName in componentNames[1:]:
+                component = getattr(component, componentName)
+        except AttributeError:
+            logs.info('Unknown Python class = "%s"' % classPath)
+            return None
+        return component
+
     def doHttpAccess(self):
         return self