1 #

     2 # Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies).

     3 # All rights reserved.

     4 # This component and the accompanying materials are made available

     5 # under the terms of "Eclipse Public License v1.0"

     6 # which accompanies this distribution, and is available

     7 # at the URL "http://www.eclipse.org/legal/epl-v10.html".

     8 #

     9 # Initial Contributors:

    10 # Nokia Corporation - initial contribution.

    11 #

    12 # Contributors:

    13 #

    14 # Description: 

    15 #

    16 

    17 import sys

    18 import logging

    19 import inspect

    20 

    21 def load_plugin_classes(entry_point_group, base_class):

    22     """

    23     Load plugin classes from plug-in entry points.

    24     

    25     @param entry_point_group: Entry point group from which to load

    26         classes. Each entry point is expected to be an iterable of

    27         plugin class instances.

    28     @param base_class: The base class that every loaded class must inherit.

    29     @return: List of loaded plugin classes.

    30     """

    31     log = logging.getLogger('cone')

    32     log.setLevel(logging.DEBUG)

    33     validator_classes = []

    34     

    35     import pkg_resources

    36     working_set = pkg_resources.WorkingSet(sys.path)

    37     for entry_point in working_set.iter_entry_points(entry_point_group):

    38         class_list = entry_point.load()

    39         

    40         # Make sure that the class list is a list

    41         try:

    42             class_list = [c for c in class_list]

    43         except:

    44             log.warn("Entry point %s:%s is not iterable (%r)" % (entry_point_group, entry_point.name, class_list))

    45             continue

    46         

    47         for i, cls in enumerate(class_list):

    48             if not inspect.isclass(cls):

    49                 log.warn("Object %d from entry point %s:%s is not a class (%r)" % (i, entry_point_group, entry_point.name, cls))

    50             elif not issubclass(cls, base_class):

    51                 log.warn("Object %d from entry point %s:%s is not a sub-class of %s.%s (%r)" \

    52                          % (i, entry_point, entry_point.name,

    53                             base_class.__module__,

    54                             base_class.__name__,

    55                             cls))

    56             else:

    57                 msg = "Validator class %r loaded from egg entry point %s:%s, item %d" % (cls, entry_point_group, entry_point.name, i)

    58                 log.debug(msg)

    59                 #print msg

    60                 validator_classes.append(cls)

    61             

    62     return validator_classes

    63 

    64 def filter_classes(classes, filter):

    65     """

    66     Filter the given list of validator by the given ProblemTypeFilter object.

    67     

    68     @param classes: The class list for filter. Each 

    69         class is assumed to have a PROBLEM_TYPES attribute that defines

    70         an iterable of the types of problems that the problem yields.

    71     @param filter: The filter object to use. Can be None, in which case

    72         the class list is simply returned back.

    73     @return: The filtered list.

    74     """

    75     if filter == None:

    76         return classes

    77     else:

    78         result = []

    79         for klass in classes:

    80             for problem_type in klass.PROBLEM_TYPES:

    81                 if filter.match(problem_type):

    82                     result.append(klass)

    83                     break

    84         return result