def cursor(self, filter=None, sort=None, hints=None):
"""
Returns a :class:`Cursor <geoscript.layer.cursor.Cursor>` over the features of the layer.
*filter* is a optional :class:`Filter <geoscript.filter.Filter>` to constrain the features iterated over.
*sort* is an optional tuple or ``list`` of tuples that defined the order in
which features are iterated over. The first value of each tuple is the name
of a field to sort on. The second value is one of the strings 'ASC' or
'DESC', representing ascending and decending sort order respectively.
>>> l = Layer()
>>> from geoscript import geom
>>> l.add([geom.Point(1,2)])
>>> l.add([geom.Point(3,4)])
>>> l.add([geom.Point(5,6)])
>>> l.add([geom.Point(7,8)])
>>> l.add([geom.Point(9,10)])
>>> c = l.cursor()
>>> f = c.next()
>>> f.geom
POINT (1 2)
>>> f = c.next()
>>> f.geom
POINT (3 4)
>>> features = c.read(2)
>>> len(features)
2
>>> features[0].geom
POINT (5 6)
>>> features[1].geom
POINT (7 8)
>>> features = c.read(2)
>>> len(features)
1
>>> features[0].geom
POINT (9 10)
>>> c.close()
"""
f = Filter(filter) if filter else Filter.PASS
q = DefaultQuery(self.name, f._filter)
if sort:
sort = sort if isinstance(sort, list) else [sort]
sortBy = []
ff = _filterFactory
for s in sort:
s = s if isinstance(s, tuple) else [s, 'ASC']
sortBy.append(ff.sort(s[0], SortOrder.valueOf(s[1])))
q.setSortBy(sortBy)
if self.proj:
q.coordinateSystem = self.proj._crs
if hints is not None:
q.setHints(Hints(hints))
fcol = self._source.getFeatures(q)
#r = self._source.dataStore.getFeatureReader(q,Transaction.AUTO_COMMIT)
return Cursor(fcol, self)
def __init__(self,
format,
file=None,
proj=None,
coverage=None,
reader=None,
mode='r'):
self.file = file
self._format = format
self._coverage = coverage
self._reader = reader
self.mode = mode
if mode == 'r':
if not coverage:
if not reader:
hints = Hints()
if proj:
proj = Projection(proj)
hints.put(Hints.DEFAULT_COORDINATE_REFERENCE_SYSTEM,
proj._crs)
self._reader = format.getReader(util.toFile(file), hints)
self._coverage = self._reader.read(None)
