Even less metaclass usage

Author: honzakral

elasticsearch_dsl/aggs.py

@@ -1,6 +1,5 @@
-from six import add_metaclass
 
-from .utils import DslMeta, DslBase, _make_dsl_class
+from .utils import DslBase, _make_dsl_class
 
 def A(name_or_agg, **params):
     # {"terms": {"field": "tags"}, "aggs": {...}}
@@ -29,7 +28,6 @@ def A(name_or_agg, **params):
     # "terms", field="tags"
     return Agg.get_dsl_class(name_or_agg)(**params)
 
-@add_metaclass(DslMeta)
 class Agg(DslBase):
     _type_name = 'agg'
     _type_shortcut = staticmethod(A)

elasticsearch_dsl/filter.py

@@ -1,6 +1,4 @@
-from six import add_metaclass
-
-from .utils import DslMeta, DslBase, BoolMixin, _make_dsl_class
+from .utils import DslBase, BoolMixin, _make_dsl_class
 
 def F(name_or_filter, filters=None, **params):
     # 'and/or', [F(), F()]
@@ -26,7 +24,6 @@ def F(name_or_filter, filters=None, **params):
     # 'term', tag='python', ...
     return Filter.get_dsl_class(name_or_filter)(**params)
 
-@add_metaclass(DslMeta)
 class Filter(DslBase):
     _type_name = 'filter'
     _type_shortcut = staticmethod(F)

elasticsearch_dsl/function.py

@@ -1,6 +1,4 @@
-from six import add_metaclass
-
-from .utils import DslMeta, DslBase
+from .utils import DslBase
 
 def SF(name_or_sf, **params):
     # {"script_score": {"script": "_score"}, "filter": {}}
@@ -30,7 +28,6 @@ def SF(name_or_sf, **params):
     # "script_score", script="_score", filter=F()
     return ScoreFunction.get_dsl_class(name_or_sf)(**params)
 
-@add_metaclass(DslMeta)
 class ScoreFunction(DslBase):
     _type_name = 'score_function'
     _type_shortcut = staticmethod(SF)

elasticsearch_dsl/query.py

@@ -1,6 +1,4 @@
-from six import add_metaclass
-
-from .utils import DslMeta, DslBase, BoolMixin, _make_dsl_class
+from .utils import DslBase, BoolMixin, _make_dsl_class
 from .function import SF, ScoreFunction
 
 def Q(name_or_query, **params):
@@ -23,7 +21,6 @@ def Q(name_or_query, **params):
     # "match", title="python"
     return Query.get_dsl_class(name_or_query)(**params)
 
-@add_metaclass(DslMeta)
 class Query(DslBase):
     _type_name = 'query'
     _type_shortcut = staticmethod(Q)

elasticsearch_dsl/utils.py

@@ -1,6 +1,6 @@
 from __future__ import unicode_literals
 
-from six import iteritems
+from six import iteritems, add_metaclass
 
 from .exceptions import UnknownDslObject
 
@@ -81,6 +81,43 @@ def to_dict(self):
         return self._d_
 
 
+class DslMeta(type):
+    """
+    Base Metaclass for DslBase subclasses that builds a registry of all classes
+    for given DslBase subclass (== all the query types for the Query subclass
+    of DslBase).
+
+    It then uses the information from that registry (as well as `name` and
+    `shortcut` attributes from the base class) to construct any subclass based
+    on it's name.
+
+    For typical use see `QueryMeta` and `Query` in `elasticsearch_dsl.query`.
+    """
+    _types = {}
+    def __init__(cls, name, bases, attrs):
+        super(DslMeta, cls).__init__(name, bases, attrs)
+        # skip for DslBase
+        if not hasattr(cls, '_type_shortcut'):
+            return
+        if cls.name is None:
+            # abstract base class, register it's shortcut
+            cls._types[cls._type_name] = cls._type_shortcut
+            # and create a registry for subclasses
+            if not hasattr(cls, '_classes'):
+                cls._classes = {}
+        else:
+            # normal class, register it
+            cls._classes[cls.name] = cls
+
+    @classmethod
+    def get_dsl_type(cls, name):
+        try:
+            return cls._types[name]
+        except KeyError:
+            raise UnknownDslObject('DSL type %s does not exist.' % name)
+
+
+@add_metaclass(DslMeta)
 class DslBase(object):
     """
     Base class for all DSL objects - queries, filters, aggregations etc. Wraps
@@ -243,39 +280,6 @@ def __and__(self, other):
         return self._bool(must=[self, other])
 
 
-class DslMeta(type):
-    """
-    Base Metaclass for DslBase subclasses that builds a registry of all classes
-    for given DslBase subclass (== all the query types for the Query subclass
-    of DslBase).
-
-    It then uses the information from that registry (as well as `name` and
-    `shortcut` attributes from the base class) to construct any subclass based
-    on it's name.
-
-    For typical use see `QueryMeta` and `Query` in `elasticsearch_dsl.query`.
-    """
-    _types = {}
-    def __init__(cls, name, bases, attrs):
-        super(DslMeta, cls).__init__(name, bases, attrs)
-        if cls.name is None:
-            # abstract base class, register it's shortcut
-            cls._types[cls._type_name] = cls._type_shortcut
-            # and create a registry for subclasses
-            if not hasattr(cls, '_classes'):
-                cls._classes = {}
-        else:
-            # normal class, register it
-            cls._classes[cls.name] = cls
-
-    @classmethod
-    def get_dsl_type(cls, name):
-        try:
-            return cls._types[name]
-        except KeyError:
-            raise UnknownDslObject('DSL type %s does not exist.' % name)
-
-
 class BoolMixin(object):
     """
     Mixin containing all the operator overrides for Bool queries and filters.