add validator support

saucebrush/filters.py

@@ -97,18 +97,31 @@ class ConditionalFilter(YieldFilter):
         All derived filters must provide a test_record(self, record) that
         returns True or False -- True indicating that the record should be
         passed through, and False preventing pass through.
+
+        If validator is True then raises a ValidationError instead of
+        silently dropping records that fail test_record.
     """
+
+    validator = False
+
     def process_record(self, record):
         """ Yields all records for which self.test_record is true """
 
         if self.test_record(record):
             yield record
+        elif self.validator:
+            raise ValidationError(record)
 
     def test_record(self, record):
         """ Given a record, return True iff it should be passed on """
         raise NotImplementedError('test_record not defined in ' +
                                   self.__class__.__name__)
 
+class ValidationError(Exception):
+    def __init__(self, record):
+        super(ValidationError, self).__init__(repr(record))
+        self.record = record
+
 #####################
 ## Generic Filters ##
 #####################
@@ -339,6 +352,10 @@ class Unique(ConditionalFilter):
         else:
             return False
 
+class UniqueValidator(Unique):
+    validator = True
+
+
 class UniqueID(ConditionalFilter):
     """ Filter that ensures that all records through have a unique ID.
 
@@ -360,6 +377,10 @@ class UniqueID(ConditionalFilter):
         else:
             return False
 
+class UniqueIDValidator(UniqueID):
+    validator = True
+
+
 class UnicodeFilter(Filter):
     """ Convert all str elements in the record to Unicode.
     """