addresses #4, allows third party software to define which indexes are…

… used
zopefoundation · Feb 8, 2019 · ce411f5 · ce411f5
1 parent 2d5ead3
commit ce411f5
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diff --git a/CHANGES.rst b/CHANGES.rst
@@ -1,7 +1,7 @@
 CHANGES
 *******
 
-0.7.2 (unreleased)
+0.8.0 (unreleased)
 ==================
 
 Breaking changes:
@@ -10,7 +10,8 @@ Breaking changes:
 
 New features:
 
-- *add item here*
+- addresses #4, allows third party software to define which indexes are used.
+  [jensens]
 
 Bug fixes:
 

diff --git a/src/z3c/relationfield/index.py b/src/z3c/relationfield/index.py
@@ -5,6 +5,35 @@
 
 import BTrees
 
+DEFAULT_INDEXES = [
+    {
+        'name': 'from_id',
+    },
+    {
+        'name': 'to_id',
+    },
+    {
+        'name': 'from_attribute',
+        'kwargs': {
+            'btree': BTrees.family32.OI,
+        },
+    },
+    {
+        'name': 'from_interfaces_flattened',
+        'kwargs': {
+            'btree': BTrees.family32.OI,
+            'multiple': True,
+        },
+    },
+    {
+        'name': 'to_interfaces_flattened',
+        'kwargs': {
+            'btree': BTrees.family32.OI,
+            'multiple': True,
+        },
+    },
+]
+
 
 def dump(obj, catalog, cache):
     intids = cache.get('intids')
@@ -22,15 +51,14 @@ def load(token, catalog, cache):
 
 class RelationCatalog(Catalog):
 
-    def __init__(self):
+    def __init__(self, indexes=DEFAULT_INDEXES):
+        """initialize the catalog with indexes.with
+
+        Uses defaults if not special configuration was passed.was
+        """
         Catalog.__init__(self, dump, load)
-        self.addValueIndex(IRelationValue['from_id'])
-        self.addValueIndex(IRelationValue['to_id'])
-        self.addValueIndex(IRelationValue['from_attribute'],
-                           btree=BTrees.family32.OI)
-        self.addValueIndex(IRelationValue['from_interfaces_flattened'],
-                           multiple=True,
-                           btree=BTrees.family32.OI)
-        self.addValueIndex(IRelationValue['to_interfaces_flattened'],
-                           multiple=True,
-                           btree=BTrees.family32.OI)
+        for index in indexes:
+            self.addValueIndex(
+                IRelationValue[index['name']],
+                **index.get('kwargs', {})
+            )