Thuban/Model/session.py

# Copyright (c) 2001, 2002 by Intevation GmbH
# Authors:
# Bernhard Herzog <[email protected]>
# Jan-Oliver Wagner <[email protected]>
#
# This program is free software under the GPL (>=v2)
# Read the file COPYING coming with Thuban for details.

__version__ = "$Revision$"

from Thuban.Lib.connector import Publisher

from messages import MAPS_CHANGED, EXTENSIONS_CHANGED, FILENAME_CHANGED, \
     LAYERS_CHANGED, MAP_PROJECTION_CHANGED, \
     LAYER_LEGEND_CHANGED, LAYER_PROJECTION_CHANGED, LAYER_VISIBILITY_CHANGED,\
     EXTENSION_CHANGED, EXTENSION_OBJECTS_CHANGED, CHANGED

from base import TitledObject, Modifiable

from map import Map


class Session(TitledObject, Modifiable):

    """A complete session.

    A Session consists of arbitrary numbers of maps, tables and extensions

    Session objects send the following events:

        TITLE_CHANGED -- The title has changed. Parameters: the session.

        FILENAME_CHANGED -- The filename has changed. No parameters.

        MAPS_CHANGED -- Maps were added, removed.

        EXTENSIONS_CHANGED -- Extensions were added, removed.

        LAYERS_CHANGED -- Same as the map's event of the same name.
                          It's simply resent from the session to make
                          subscriptions easier.

        CHANGED -- Generic changed event. Parameters: the session. The
                   event is always issued when any other changed event
                   is issused. This is useful for code that needs to be
                   notified whenever something in the session has
                   changed but it's too cumbersome or error-prone to
                   subscribe to all the individual events.
    """

    # message channels that have to be forwarded from maps contained in
    # the session.
    forwarded_channels = (
        # map specific channels
        MAP_PROJECTION_CHANGED,
        LAYERS_CHANGED,

        # layer channels forwarded by the map
        LAYER_PROJECTION_CHANGED,
        LAYER_LEGEND_CHANGED,
        LAYER_VISIBILITY_CHANGED,

        # channels forwarded by an extension
        EXTENSION_CHANGED,
        EXTENSION_OBJECTS_CHANGED)

    def __init__(self, title):
        TitledObject.__init__(self, title)
        Modifiable.__init__(self)
        self.filename = None
        self.maps = []
        self.tables = []
        self.extensions = []

    def changed(self, channel = None, *args):
        """Like the inherited version but issue a CHANGED message as well.

        The CHANGED message is only issued if channel given is a
        different channel than CHANGED.
        """
        Modifiable.changed(self, channel, *args)
        if channel != CHANGED:
            self.issue(CHANGED, self)

    def SetFilename(self, filename):
        self.filename = filename
        self.changed(FILENAME_CHANGED)

    def Maps(self):
        return self.maps

    def HasMaps(self):
        return len(self.maps) > 0

    def AddMap(self, map):
        self.maps.append(map)
        for channel in self.forwarded_channels:
            map.Subscribe(channel, self.forward, channel)
        self.changed(MAPS_CHANGED)

    def Extensions(self):
        return self.extensions

    def HasExtensions(self):
        return len(self.extensions) > 0

    def AddExtension(self, extension):
        self.extensions.append(extension)
        for channel in self.forwarded_channels:
            extension.Subscribe(channel, self.forward, channel)
        self.changed(EXTENSIONS_CHANGED)

    def Destroy(self):
        for map in self.maps:
            map.Destroy()
        self.maps = []
        self.tables = []
        Publisher.Destroy(self)

    def forward(self, *args):
        """Reissue events.

        If the channel the event is forwarded to is a changed-channel
        that is not the CHANGED channel issue CHANGED as well. An
        channel is considered to be a changed-channel if it's name ends
        with 'CHANGED'.
        """
        if len(args) > 1:
            args = (args[-1],) + args[:-1]
        apply(self.issue, args)
        channel = args[0]
        # It's a bit of a kludge to rely on the channel name for this.
        if channel.endswith("CHANGED") and channel != CHANGED:
            self.issue(CHANGED, self)

    def WasModified(self):
        """Return true if the session or one of the maps was modified"""
        if self.modified:
            return 1
        else:
            for map in self.maps:
                if map.WasModified():
                    return 1
        return 0

    def UnsetModified(self):
        """Unset the modified flag of the session and the maps"""
        Modifiable.UnsetModified(self)
        for map in self.maps:
            map.UnsetModified()

    def TreeInfo(self):
        items = []
        if self.filename is None:
            items.append("Filename:")
        else:
            items.append("Filename: %s" % self.filename)

        if self.WasModified():
            items.append("Modified")
        else:
            items.append("Unmodified")

        items.extend(self.maps)
        items.extend(self.extensions)

        return ("Session: %s" % self.title, items)


def create_empty_session():
    """Return an empty session useful as a starting point"""
    import os
    session = Session('unnamed session')
    session.SetFilename(None)
    session.AddMap(Map('unnamed map'))
    session.UnsetModified()
    return session
1	# Copyright (c) 2001, 2002 by Intevation GmbH
2	# Authors:
3	# Bernhard Herzog <[email protected]>
4	# Jan-Oliver Wagner <[email protected]>
5	#
6	# This program is free software under the GPL (>=v2)
7	# Read the file COPYING coming with Thuban for details.
8
9	__version__ = "$Revision$"
10
11	from Thuban.Lib.connector import Publisher
12
13	from messages import MAPS_CHANGED, EXTENSIONS_CHANGED, FILENAME_CHANGED, \
14	LAYERS_CHANGED, MAP_PROJECTION_CHANGED, \
15	LAYER_LEGEND_CHANGED, LAYER_PROJECTION_CHANGED, LAYER_VISIBILITY_CHANGED,\
16	EXTENSION_CHANGED, EXTENSION_OBJECTS_CHANGED, CHANGED
17
18	from base import TitledObject, Modifiable
19
20	from map import Map
21
22
23	class Session(TitledObject, Modifiable):
24
25	"""A complete session.
26
27	A Session consists of arbitrary numbers of maps, tables and extensions
28
29	Session objects send the following events:
30
31	TITLE_CHANGED -- The title has changed. Parameters: the session.
32
33	FILENAME_CHANGED -- The filename has changed. No parameters.
34
35	MAPS_CHANGED -- Maps were added, removed.
36
37	EXTENSIONS_CHANGED -- Extensions were added, removed.
38
39	LAYERS_CHANGED -- Same as the map's event of the same name.
40	It's simply resent from the session to make
41	subscriptions easier.
42
43	CHANGED -- Generic changed event. Parameters: the session. The
44	event is always issued when any other changed event
45	is issused. This is useful for code that needs to be
46	notified whenever something in the session has
47	changed but it's too cumbersome or error-prone to
48	subscribe to all the individual events.
49	"""
50
51	# message channels that have to be forwarded from maps contained in
52	# the session.
53	forwarded_channels = (
54	# map specific channels
55	MAP_PROJECTION_CHANGED,
56	LAYERS_CHANGED,
57
58	# layer channels forwarded by the map
59	LAYER_PROJECTION_CHANGED,
60	LAYER_LEGEND_CHANGED,
61	LAYER_VISIBILITY_CHANGED,
62
63	# channels forwarded by an extension
64	EXTENSION_CHANGED,
65	EXTENSION_OBJECTS_CHANGED)
66
67	def __init__(self, title):
68	TitledObject.__init__(self, title)
69	Modifiable.__init__(self)
70	self.filename = None
71	self.maps = []
72	self.tables = []
73	self.extensions = []
74
75	def changed(self, channel = None, *args):
76	"""Like the inherited version but issue a CHANGED message as well.
77
78	The CHANGED message is only issued if channel given is a
79	different channel than CHANGED.
80	"""
81	Modifiable.changed(self, channel, *args)
82	if channel != CHANGED:
83	self.issue(CHANGED, self)
84
85	def SetFilename(self, filename):
86	self.filename = filename
87	self.changed(FILENAME_CHANGED)
88
89	def Maps(self):
90	return self.maps
91
92	def HasMaps(self):
93	return len(self.maps) > 0
94
95	def AddMap(self, map):
96	self.maps.append(map)
97	for channel in self.forwarded_channels:
98	map.Subscribe(channel, self.forward, channel)
99	self.changed(MAPS_CHANGED)
100
101	def Extensions(self):
102	return self.extensions
103
104	def HasExtensions(self):
105	return len(self.extensions) > 0
106
107	def AddExtension(self, extension):
108	self.extensions.append(extension)
109	for channel in self.forwarded_channels:
110	extension.Subscribe(channel, self.forward, channel)
111	self.changed(EXTENSIONS_CHANGED)
112
113	def Destroy(self):
114	for map in self.maps:
115	map.Destroy()
116	self.maps = []
117	self.tables = []
118	Publisher.Destroy(self)
119
120	def forward(self, *args):
121	"""Reissue events.
122
123	If the channel the event is forwarded to is a changed-channel
124	that is not the CHANGED channel issue CHANGED as well. An
125	channel is considered to be a changed-channel if it's name ends
126	with 'CHANGED'.
127	"""
128	if len(args) > 1:
129	args = (args[-1],) + args[:-1]
130	apply(self.issue, args)
131	channel = args[0]
132	# It's a bit of a kludge to rely on the channel name for this.
133	if channel.endswith("CHANGED") and channel != CHANGED:
134	self.issue(CHANGED, self)
135
136	def WasModified(self):
137	"""Return true if the session or one of the maps was modified"""
138	if self.modified:
139	return 1
140	else:
141	for map in self.maps:
142	if map.WasModified():
143	return 1
144	return 0
145
146	def UnsetModified(self):
147	"""Unset the modified flag of the session and the maps"""
148	Modifiable.UnsetModified(self)
149	for map in self.maps:
150	map.UnsetModified()
151
152	def TreeInfo(self):
153	items = []
154	if self.filename is None:
155	items.append("Filename:")
156	else:
157	items.append("Filename: %s" % self.filename)
158
159	if self.WasModified():
160	items.append("Modified")
161	else:
162	items.append("Unmodified")
163
164	items.extend(self.maps)
165	items.extend(self.extensions)
166
167	return ("Session: %s" % self.title, items)
168
169
170	def create_empty_session():
171	"""Return an empty session useful as a starting point"""
172	import os
173	session = Session('unnamed session')
174	session.SetFilename(None)
175	session.AddMap(Map('unnamed map'))
176	session.UnsetModified()
177	return session
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