adding commonal parent class LDPDocumentCollection

factored out the dict-like behaviour (and added sorting behaviour)
from SourceCollection and OutputCollection to LDPDocumentCollection

tldp/ldpcollection.py

@@ -0,0 +1,56 @@
+#! /usr/bin/python
+# -*- coding: utf8 -*-
+
+from __future__ import absolute_import, division, print_function
+
+import collections
+
+
+class LDPDocumentCollection(collections.MutableMapping):
+    '''a dict-like container for DocumentCollection objects
+
+    Intended to be subclassed.
+
+    Implements all the usual dictionary stuff, but also provides sorted
+    lists of documents in the collection.
+    '''
+    def __repr__(self):
+        return '<%s:(%s docs)>' % (self.__class__.__name__, len(self))
+
+    def __delitem__(self, key):
+        del self.__dict__[key]
+
+    def __getitem__(self, key):
+        return self.__dict__[key]
+
+    def __setitem__(self, key, value):
+        self.__dict__[key] = value
+
+    def __iter__(self):
+        return iter(self.__dict__)
+
+    def __len__(self):
+        return len(self.__dict__)
+
+    def iterkeys(self):
+        return iter(self.keys)
+
+    def itervalues(self):
+        for key in sorted(self, key=lambda x: x.lower()):
+            yield self[key]
+
+    def iteritems(self):
+        for key in self.keys:
+            yield (key, self[key])
+
+    def keys(self):
+        return sorted(self, key=lambda x: x.lower())
+
+    def items(self):
+        return [(key, self[key]) for key in self.keys()]
+
+    def values(self):
+        return [self[key] for key in self.keys()]
+
+#
+# -- end of file