Thuban/Model/data.py

# Copyright (C) 2003 by Intevation GmbH
# Authors:
# Bernhard Herzog <[email protected]>
#
# This program is free software under the GPL (>=v2)
# Read the file COPYING coming with the software for details.

"""Data source abstractions"""

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

import os
import weakref

import shapelib
import table
import transientdb

from Thuban import _


class ShapeTable(transientdb.AutoTransientTable):

    """A Table that depends on a ShapefileStore

    Intended use is by the ShapefileStore for the table associated with
    the shapefiles.
    """

    def __init__(self, store, db, table):
        """Initialize the ShapeTable.

        Parameters:
            store -- the ShapefileStore the table is to depend on
            db -- The transient database to use
            table -- the table
        """
        transientdb.AutoTransientTable.__init__(self, db, table)
        self.store = weakref.ref(store)

    def Dependencies(self):
        """Return a tuple containing the shapestore"""
        return (self.store(),)


class ShapefileStore:

    """Combine a shapefile and the corresponding DBF file into one object"""

    def __init__(self, session, filename):
        # Make the filename absolute. The filename will be
        # interpreted relative to that anyway, but when saving a
        # session we need to compare absolute paths and it's usually
        # safer to always work with absolute paths.
        self.filename = os.path.abspath(filename)

        self.shapefile = shapelib.ShapeFile(self.filename)
        self.dbftable = table.DBFTable(filename)
        self.table = ShapeTable(self, session.TransientDB(), self.dbftable)

    def Table(self):
        """Return the table containing the attribute data"""
        return self.table

    def Shapefile(self):
        """Return the shapefile object"""
        return self.shapefile

    def FileName(self):
        """Return the filename used to open the shapefile"""
        return self.filename

    def FileType(self):
        """Return the filetype. This is always the string 'shapefile'"""
        return "shapefile"

    def Dependencies(self):
        """Return the empty tuple.

        The ShapefileStore doesn't depend on anything else.
        """
        return ()

    def OrigShapeStore(self):
        """Return None.

        The ShapefileStore was not derived from another shapestore.
        """
        return None


class DerivedShapeStore:

    """A ShapeStore derived from other shapestores or tables"""

    def __init__(self, shapestore, table):
        """Initialize the derived shapestore.

        The arguments are a shapestore for the shapedata and a table for
        the tabular data.

        Raises ValueError if the number of shapes in the shapestore
        is different from the number of rows in the table.
        """

        numShapes = shapestore.Shapefile().info()[0]
        if numShapes != table.NumRows():
            raise ValueError(_("Table not compatible with shapestore."))

        self.shapestore = shapestore
        self.table = table

    def Table(self):
        """Return the table"""
        return self.table

    def Shapefile(self):
        """Return the shapefile of the underlying shapestore"""
        return self.shapestore.Shapefile()

    def Dependencies(self):
        """Return a tuple containing the shapestore and the table"""
        return (self.shapestore, self.table)

    def OrigShapeStore(self):
        """
        Return the original shapestore the derived store was instantiated with
        """
        return self.shapestore
1	# Copyright (C) 2003 by Intevation GmbH
2	# Authors:
3	# Bernhard Herzog <[email protected]>
4	#
5	# This program is free software under the GPL (>=v2)
6	# Read the file COPYING coming with the software for details.
7
8	"""Data source abstractions"""
9
10	__version__ = "$Revision$"
11	# $Source$
12	# $Id$
13
14	import os
15	import weakref
16
17	import shapelib
18	import table
19	import transientdb
20
21	from Thuban import _
22
23
24	class ShapeTable(transientdb.AutoTransientTable):
25
26	"""A Table that depends on a ShapefileStore
27
28	Intended use is by the ShapefileStore for the table associated with
29	the shapefiles.
30	"""
31
32	def __init__(self, store, db, table):
33	"""Initialize the ShapeTable.
34
35	Parameters:
36	store -- the ShapefileStore the table is to depend on
37	db -- The transient database to use
38	table -- the table
39	"""
40	transientdb.AutoTransientTable.__init__(self, db, table)
41	self.store = weakref.ref(store)
42
43	def Dependencies(self):
44	"""Return a tuple containing the shapestore"""
45	return (self.store(),)
46
47
48	class ShapefileStore:
49
50	"""Combine a shapefile and the corresponding DBF file into one object"""
51
52	def __init__(self, session, filename):
53	# Make the filename absolute. The filename will be
54	# interpreted relative to that anyway, but when saving a
55	# session we need to compare absolute paths and it's usually
56	# safer to always work with absolute paths.
57	self.filename = os.path.abspath(filename)
58
59	self.shapefile = shapelib.ShapeFile(self.filename)
60	self.dbftable = table.DBFTable(filename)
61	self.table = ShapeTable(self, session.TransientDB(), self.dbftable)
62
63	def Table(self):
64	"""Return the table containing the attribute data"""
65	return self.table
66
67	def Shapefile(self):
68	"""Return the shapefile object"""
69	return self.shapefile
70
71	def FileName(self):
72	"""Return the filename used to open the shapefile"""
73	return self.filename
74
75	def FileType(self):
76	"""Return the filetype. This is always the string 'shapefile'"""
77	return "shapefile"
78
79	def Dependencies(self):
80	"""Return the empty tuple.
81
82	The ShapefileStore doesn't depend on anything else.
83	"""
84	return ()
85
86	def OrigShapeStore(self):
87	"""Return None.
88
89	The ShapefileStore was not derived from another shapestore.
90	"""
91	return None
92
93
94	class DerivedShapeStore:
95
96	"""A ShapeStore derived from other shapestores or tables"""
97
98	def __init__(self, shapestore, table):
99	"""Initialize the derived shapestore.
100
101	The arguments are a shapestore for the shapedata and a table for
102	the tabular data.
103
104	Raises ValueError if the number of shapes in the shapestore
105	is different from the number of rows in the table.
106	"""
107
108	numShapes = shapestore.Shapefile().info()[0]
109	if numShapes != table.NumRows():
110	raise ValueError(_("Table not compatible with shapestore."))
111
112	self.shapestore = shapestore
113	self.table = table
114
115	def Table(self):
116	"""Return the table"""
117	return self.table
118
119	def Shapefile(self):
120	"""Return the shapefile of the underlying shapestore"""
121	return self.shapestore.Shapefile()
122
123	def Dependencies(self):
124	"""Return a tuple containing the shapestore and the table"""
125	return (self.shapestore, self.table)
126
127	def OrigShapeStore(self):
128	"""
129	Return the original shapestore the derived store was instantiated with
130	"""
131	return self.shapestore
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