Added a MonthYear field, fixed some field required values and fixed

validation functions. Added numeric state abbreviation capability.
So far everything appears to be working good.

fields.py

@@ -1,7 +1,17 @@
 import decimal, datetime
+import inspect
+from enums import STATE_POSTAL_NUMERIC
 
 class ValidationError(Exception):
-    pass
+    def __init__(self, msg, field=None):
+        self.msg = msg
+        self.field = field
+
+    def __str__(self):
+        if self.field:
+            return "(%s.%s) %s" % (self.field.parent_name, self.field.name, self.msg)
+        else:
+            return repr(self.msg)
 
 class Field(object):
     creation_counter = 0
@@ -42,9 +52,9 @@ class Field(object):
 class TextField(Field):    
     def validate(self):
         if self.value == None and self.required:
-            raise ValidationError("value required")
-        if len(self.value) > self.max_length:
-            raise ValidationError("value is too long")
+            raise ValidationError("value required", field=self)
+        if len(self.get_data()) > self.max_length:
+            raise ValidationError("value is too long", field=self)
 
     def get_data(self):
         value = self.value or ""
@@ -54,9 +64,28 @@ class TextField(Field):
 
 
 class StateField(TextField):
-    def __init__(self, name=None, required=True):
-        return super(StateField, self).__init__(name=name, max_length=2, required=required)
+    def __init__(self, name=None, required=True, use_numeric=False):
+        super(StateField, self).__init__(name=name, max_length=2, required=required)
+        self.use_numeric = use_numeric
 
+    def get_data(self):
+        value = self.value or ""
+        if value.strip() and self.use_numeric:
+            return str(STATE_POSTAL_NUMERIC[value.upper()]).zfill(self.max_length)
+        else:
+            return value.ljust(self.max_length).encode('ascii')
+
+    def validate(self):
+        super(StateField, self).validate()
+        if self.value and self.value.upper() not in STATE_POSTAL_NUMERIC.keys():
+            raise ValidationError("%s is not a valid state abbreviation" % self.value, field=self)
+
+    def parse(self, s):
+        if s.strip() and self.use_numeric:
+            states = dict( [(v,k) for (k,v) in STATE_POSTAL_NUMERIC.items()] )
+            self.value = states[int(s)]
+        else:
+            self.value = s
 
 class EmailField(TextField):
     def __init__(self, name=None, required=True, max_length=None):
@@ -66,14 +95,16 @@ class EmailField(TextField):
 class NumericField(TextField):
     def validate(self):
         super(NumericField, self).validate()
-        try:
-            int(self.value)
-        except ValueError:
-            raise ValidationError("field contains non-numeric characters")
+        if self.value:
+            try:
+                int(self.value)
+            except ValueError:
+                raise ValidationError("field contains non-numeric characters", field=self)
+         
 
     def get_data(self):
         value = self.value or ""
-        return value.zfill(self.max_length)
+        return str(value).zfill(self.max_length)
 
     def parse(self, s):
         self.value = int(s)
@@ -89,6 +120,9 @@ class StaticField(TextField):
         pass
 
 class BlankField(TextField):
+    def __init__(self, name=None, max_length=0, required=False):
+        super(TextField, self).__init__(name=name, max_length=max_length, required=required, uppercase=False)
+    
     def get_data(self):
         return " " * self.max_length
 
@@ -109,12 +143,13 @@ class BooleanField(Field):
     def parse(self, s):
         self.value = (s == '1')
 
+
 class MoneyField(Field):
     def validate(self):
         if self.value == None and self.required:
-            raise ValidationError("value required")
+            raise ValidationError("value required", field=self)
         if len(str(int((self.value or 0)*100))) > self.max_length:
-            raise ValidationError("value is too long")
+            raise ValidationError("value is too long", field=self)
 
     def get_data(self):
         return str(int((self.value or 0)*100)).encode('ascii').zfill(self.max_length)
@@ -122,15 +157,12 @@ class MoneyField(Field):
     def parse(self, s):
         self.value = decimal.Decimal(s) * decimal.Decimal('0.01')
 
+
 class DateField(TextField):
     def __init__(self, name=None, required=True, value=None):
-        super(TextField, self).__init__(name=name, required=required, max_length=8)
-        if isinstance(value, datetime.date):
-            self._value = value
-        elif value:
-            self._value = datetime.date(*[int(x) for x in value[4:8], value[0:2], value[2:4]])
-        else:
-            self._value = None
+        super(TextField, self).__init__(name=name, required=required, max_length=8)    
+        if value:
+            self.value = value
 
     def get_data(self):
         if self._value:
@@ -138,6 +170,53 @@ class DateField(TextField):
         return '0' * self.max_length
         
     def parse(self, s):
-        self.value = datetime.date(*[int(x) for x in s[4:8], s[0:2], s[2:4]])
+        if int(s) > 0:
+            self.value = datetime.date(*[int(x) for x in s[4:8], s[0:2], s[2:4]])
+        else:
+            self.value = None
+
+    def __setvalue(self, value):
+        if isinstance(value, datetime.date):
+            self._value = value
+        elif value:
+            self._value = datetime.date(*[int(x) for x in value[4:8], value[0:2], value[2:4]])
+        else:
+            self._value = None
+
+    def __getvalue(self):   
+        return self._value
+ 
+    value = property(__getvalue, __setvalue)
 
 
+class MonthYearField(TextField):
+    def __init__(self, name=None, required=True, value=None):
+        super(TextField, self).__init__(name=name, required=required, max_length=6)
+
+        if value:
+            self.value = value
+    
+    def get_data(self):
+        if self._value:
+            return self._value.strftime("%m%Y")
+        return '0' * self.max_length
+
+    def parse(self, s):
+        if int(s) > 0:
+            self.value = datetime.date(*[int(x) for x in s[2:6], s[0:2], 1])
+        else:
+            self.value = None
+
+    def __setvalue(self, value):
+        if isinstance(value, datetime.date):
+            self._value = value
+        elif value:
+            self._value = datetime.date(*[int(x) for x in value[2:6], value[0:2], 1])
+        else:
+            self._value = None
+    
+    def __getvalue(self):   
+        return self._value
+ 
+    value = property(__getvalue, __setvalue)
+