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# This file is part of pybliographer
#
# Copyright (C) 1998-2004 Frederic GOBRY
# Email : gobry@pybliographer.org
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
#
#
from Pyblio.Iterator import Iterator
class SearchSelection (Iterator):
''' Iterates on a subset of another iterator. The subset is
defined by a Search object '''
def __init__ (self, search, iterator):
self.search = search
self.iter = iterator
self.base = iterator.base
return
def __iter__ (self):
test = self.search.match
for i in self.iter :
if test(i):
yield i
raise StopIteration
def first (self):
entry = self.iter.first ()
if not entry: return None
while not self.search.match (entry):
entry = self.iter.next ()
if not entry: return None
return entry
def next (self):
entry = self.iter.next ()
if not entry: return None
while not self.search.match (entry):
entry = self.iter.next ()
if not entry: return None
return entry
def __str__ (self):
return '<Search Iterator on %s>' % self.search
class SortSelection (Iterator):
''' Iterates on a sorted version of another iterator. The sort
criterion is defined by a Sort object '''
def __init__ (self, sort, iterator):
# compute asap
self.data = sort.sort (iterator)
self.base = iterator.base
self.count = 0
return
def __iter__ (self):
self.count = 0
for i in self.data:
yield i
self.count += 1
raise StopIteration
def first (self):
self.count = 0
return self.next ()
def next (self):
try:
ret = self.data [self.count]
except IndexError:
return None
self.count = self.count + 1
return ret
def __str__ (self):
return '<Sort Iterator>'
class Selection:
''' This class provides iterators that implement constraints (like
sorting and searching) on another iterator '''
def __init__ (self, search = None, sort = None):
self.search = search
self.sort = sort
return
def iterator (self, iterator):
''' returns an iterator that will provide the entries of the
database according to the properties of the current Selection
'''
# no filtering ? then pass through
if not self.search and not self.sort:
return iterator
if not self.sort:
return SearchSelection (self.search, iterator)
if not self.search:
return SortSelection (self.sort, iterator)
return SortSelection (self.sort,
SearchSelection (self.search, iterator))
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