#!/usr/bin/env python
# ClusterDriverFactory.py
#
#   Copyright (C) 2006 CCLRC, Graeme Winter
#
#   This code is distributed under the BSD license, a copy of which is 
#   included in the root directory of this package.
#
# 19th June 2006
# 
# A DriverFactory for cluster-specific driver instances.
# At the moment this supports the following machines:
# 
# Linux/Sun Grid Engine
# 
# 

import os

from SunGridEngineClusterDriver import SunGridEngineClusterDriver

class _ClusterDriverFactory:

    def __init__(self):

        self._driver_type = 'cluster.sge'

        self._implemented_types = ['cluster.sge']

        # should probably write a message or something explaining
        # that the following Driver implementation is being used

        if os.environ.has_key('XIA2CORE_DRIVERTYPE'):
            if 'cluster' in os.environ['XIA2CORE_DRIVERTYPE']:
                self.setDriver_type(os.environ['XIA2CORE_DRIVERTYPE'])

        return

    def set_driver_type(self, type):
        return self.setDriver_type(type)

    def setDriver_type(self, type):
        '''Set the kind of driver this factory should produce.'''

        if not type in self._implemented_types:
            raise RuntimeError, 'unimplemented driver class: %s' % type
        
        self._driver_type = type

        return

    def Driver(self, type = None):
        '''Create a new Driver instance, optionally providing the
        type of Driver we want.'''

        if not type:
            type = self._driver_type

        if type == 'cluster.sge':
            return SunGridEngineClusterDriver()

        raise RuntimeError, 'Driver class "%s" unknown' % type

ClusterDriverFactory = _ClusterDriverFactory()

if __name__ == '__main__':
    # then run a test

    d = ClusterDriverFactory.Driver()

    d = ClusterDriverFactory.Driver('nosuchtype')