ConditionalPathFilter

saucebrush/filters.py

@@ -172,6 +172,20 @@ class SubrecordFilter(Filter):
             self.process_subrecord(subrecord_parent)
         return record
 
+class ConditionalPathFilter(Filter):
+    """ Filter that uses a predicate to split input among two filter paths. """
+
+    def __init__(self, predicate_func, true_filter, false_filter):
+        self.predicate_func = predicate_func
+        self.true_filter = true_filter
+        self.false_filter = false_filter
+
+    def process_record(self, record):
+        if self.predicate_func(record):
+            return self.true_filter.process_record(record)
+        else:
+            return self.false_filter.process_record(record)
+
 #####################
 ## Generic Filters ##
 #####################

saucebrush/tests/filters.py

@@ -2,7 +2,7 @@ import unittest
 import operator
 import types
 from saucebrush.filters import (Filter, YieldFilter, FieldFilter,
-                                SubrecordFilter,
+                                SubrecordFilter, ConditionalPathFilter,
                                 ConditionalFilter, FieldModifier,
                                 FieldRemover, FieldMerger, FieldAdder,
                                 FieldCopier, FieldRenamer, Unique)
@@ -175,6 +175,19 @@ class FilterTestCase(unittest.TestCase):
 
         self.assertEquals(list(result), expected)
 
+    def test_conditional_path(self):
+
+        predicate = lambda r: r['a'] == 1
+
+        # double b if a == 1, otherwise double c
+        cpf = ConditionalPathFilter(predicate, FieldDoubler('b'),
+                                    FieldDoubler('c'))
+        expected_data = [{'a':1, 'b':4, 'c':3},
+                         {'a':5, 'b':5, 'c':10},
+                         {'a':1, 'b':20, 'c':100}]
+
+        self.assert_filter_result(cpf, expected_data)
+
     ### Tests for Generic Filters
 
     def test_field_modifier(self):