deb-python-cassandra-driver/cassandra/cqlengine/operators.py
2017-04-24 17:20:57 -04:00

96 lines
2.3 KiB
Python

# Copyright 2013-2017 DataStax, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import six
from cassandra.cqlengine import UnicodeMixin
class QueryOperatorException(Exception):
pass
class BaseQueryOperator(UnicodeMixin):
# The symbol that identifies this operator in kwargs
# ie: colname__<symbol>
symbol = None
# The comparator symbol this operator uses in cql
cql_symbol = None
def __unicode__(self):
if self.cql_symbol is None:
raise QueryOperatorException("cql symbol is None")
return self.cql_symbol
class OpMapMeta(type):
def __init__(cls, name, bases, dct):
if not hasattr(cls, 'opmap'):
cls.opmap = {}
else:
cls.opmap[cls.symbol] = cls
super(OpMapMeta, cls).__init__(name, bases, dct)
@six.add_metaclass(OpMapMeta)
class BaseWhereOperator(BaseQueryOperator):
""" base operator used for where clauses """
@classmethod
def get_operator(cls, symbol):
try:
return cls.opmap[symbol.upper()]
except KeyError:
raise QueryOperatorException("{0} doesn't map to a QueryOperator".format(symbol))
class EqualsOperator(BaseWhereOperator):
symbol = 'EQ'
cql_symbol = '='
class NotEqualsOperator(BaseWhereOperator):
symbol = 'NE'
cql_symbol = '!='
class InOperator(EqualsOperator):
symbol = 'IN'
cql_symbol = 'IN'
class GreaterThanOperator(BaseWhereOperator):
symbol = "GT"
cql_symbol = '>'
class GreaterThanOrEqualOperator(BaseWhereOperator):
symbol = "GTE"
cql_symbol = '>='
class LessThanOperator(BaseWhereOperator):
symbol = "LT"
cql_symbol = '<'
class LessThanOrEqualOperator(BaseWhereOperator):
symbol = "LTE"
cql_symbol = '<='
class ContainsOperator(EqualsOperator):
symbol = "CONTAINS"
cql_symbol = 'CONTAINS'