Thuban/UI/extensionregistry.py

# Copyright (C) 2004, 2005 by Intevation GmbH
# Authors:
# Jan-Oliver Wagner <[email protected]> (2004, 2005)
#
# This program is free software under the GPL (>=v2)
# Read the file COPYING coming with Thuban for details.

"""
Registry for Extensions.

This module defines a registry for Extensions.
This is basically used for displaying information on
the active Extensions in the general About-Dialog.
A registration is not mandatory to make a Extension
work, but any Extension should register to provide
a complete information in the Thuban About Dialog.

A Extension should define a ExtensionDesc object
and apply ext_registry.add() to register it.
"""

__version__ = "$Revision$"
# $Source$
# $Id$

from Thuban import _

class ExtensionDesc:

    """
    A description of a Thuban Extension.
    """

    def __init__(self, name, version, authors, copyright, desc,
                 init_callback = None):
        """
        Initialize a new Thuban Extension information.

        name -- The name of the Thuban Extension.
                Example: 'gns2shp'

        version -- The version number of the Thuban Extension.
                   Example: '1.0.0'

        authors -- List of authors.
                   Example: [ 'Jan-Oliver Wagner' ]

        copyright -- Copyright notice.
                     Example: '2003, 2004 Intevation GmbH'

        desc -- Short description of the Thuban Extension.
                Example: _('''
                         Converts GNS (Geographical Name Service of NIMA)
                         to Shapefile format and displays the data.
                         ''')
        init_callback -- a callback method that is executed if not
                         None. This method should contain gui specific
                         initializations of the extension.
                         Default is None.

                         This callback should return None if
                         the intialisation as successful. Else
                         a string describing the problems during
                         intialization.
        """
        self.name = name
        self.version = version
        self.authors = authors
        self.copyright = copyright
        self.desc = desc
        self.init_callback = init_callback
        self.status = _("Initialization not yet requested.")

    def init_ext(self):
        """Execute the init callback for the extension.

        Do nothing if the callback is None.

        It is expected that the callback function returns
        None if all was OK and a string if something was wrong.
        The string is believed to describe the problems.
        """
        if self.init_callback is not None:
            result = self.init_callback()
            if result is not None:
                self.status = result
            else:
                self.status = _("Initialization successful.")

class ExtensionRegistry:

    """
    A ExtensionRegistry keeps information on the registered
    Thuban Extensions.

    The registry will raise a exception either when the version
    required for the Extensions exceeds the version of the currently
    running Thuban or if the name of a registered extension already
    is used for registering another extension.
    """

    def __init__(self):
        self.registry = []

    def __nonzero__(self):
        return len(self.registry) <> 0

    def __iter__(self):
        return iter(self.registry)

    def add(self, ext):
        self.registry.append(ext)


# The central Thuban Extensions registry
ext_registry = ExtensionRegistry()
1	jan	2580	# Copyright (C) 2004, 2005 by Intevation GmbH
2	jan	2353	# Authors:
3	jan	2580	# Jan-Oliver Wagner <[email protected]> (2004, 2005)
4	jan	2353	#
5			# This program is free software under the GPL (>=v2)
6			# Read the file COPYING coming with Thuban for details.
7
8			"""
9			Registry for Extensions.
10
11			This module defines a registry for Extensions.
12			This is basically used for displaying information on
13			the active Extensions in the general About-Dialog.
14			A registration is not mandatory to make a Extension
15			work, but any Extension should register to provide
16			a complete information in the Thuban About Dialog.
17
18			A Extension should define a ExtensionDesc object
19			and apply ext_registry.add() to register it.
20			"""
21
22			__version__ = "$Revision$"
23			# $Source$
24			# $Id$
25
26	jan	2580	from Thuban import _
27
28	jan	2353	class ExtensionDesc:
29
30			"""
31			A description of a Thuban Extension.
32			"""
33
34	jan	2580	def __init__(self, name, version, authors, copyright, desc,
35			init_callback = None):
36	jan	2353	"""
37			Initialize a new Thuban Extension information.
38
39			name -- The name of the Thuban Extension.
40			Example: 'gns2shp'
41
42			version -- The version number of the Thuban Extension.
43			Example: '1.0.0'
44
45			authors -- List of authors.
46			Example: [ 'Jan-Oliver Wagner' ]
47
48			copyright -- Copyright notice.
49			Example: '2003, 2004 Intevation GmbH'
50
51			desc -- Short description of the Thuban Extension.
52			Example: _('''
53			Converts GNS (Geographical Name Service of NIMA)
54			to Shapefile format and displays the data.
55			''')
56	jan	2580	init_callback -- a callback method that is executed if not
57			None. This method should contain gui specific
58			initializations of the extension.
59			Default is None.
60	jan	2353
61	jan	2580	This callback should return None if
62			the intialisation as successful. Else
63			a string describing the problems during
64			intialization.
65	jan	2353	"""
66			self.name = name
67			self.version = version
68			self.authors = authors
69			self.copyright = copyright
70			self.desc = desc
71	jan	2580	self.init_callback = init_callback
72			self.status = _("Initialization not yet requested.")
73	jan	2353
74	jan	2580	def init_ext(self):
75			"""Execute the init callback for the extension.
76
77			Do nothing if the callback is None.
78
79			It is expected that the callback function returns
80			None if all was OK and a string if something was wrong.
81			The string is believed to describe the problems.
82			"""
83			if self.init_callback is not None:
84			result = self.init_callback()
85			if result is not None:
86			self.status = result
87			else:
88			self.status = _("Initialization successful.")
89
90	jan	2353	class ExtensionRegistry:
91
92			"""
93			A ExtensionRegistry keeps information on the registered
94			Thuban Extensions.
95
96			The registry will raise a exception either when the version
97			required for the Extensions exceeds the version of the currently
98			running Thuban or if the name of a registered extension already
99			is used for registering another extension.
100			"""
101
102			def __init__(self):
103			self.registry = []
104
105			def __nonzero__(self):
106			return len(self.registry) <> 0
107
108			def __iter__(self):
109			return iter(self.registry)
110
111			def add(self, ext):
112			self.registry.append(ext)
113
114
115			# The central Thuban Extensions registry
116			ext_registry = ExtensionRegistry()
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