# ====================================================================
#   Licensed under the Apache License, Version 2.0 (the "License");
#   you may not use this file except in compliance with the License.
#   You may obtain a copy of the License at
#
#       http://www.apache.org/licenses/LICENSE-2.0
#
#   Unless required by applicable law or agreed to in writing, software
#   distributed under the License is distributed on an "AS IS" BASIS,
#   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#   See the License for the specific language governing permissions and
#   limitations under the License.
# ====================================================================

from lucene import IndexReader, Term, BitSet, PythonFilter, JArray

#
# A Filter extension, with a TermDocs wrapper working around the lack of
# support for returning values in array arguments.
#
class SpecialsFilter(PythonFilter):

    def __init__(self, accessor):
        
        super(SpecialsFilter, self).__init__()
        self.accessor = accessor

    def bits(self, reader):

        bits = BitSet(reader.maxDoc())
        isbns = self.accessor.isbns()

        for isbn in isbns:
            if isbn is not None:
                termDocs = reader.termDocs(Term("isbn", isbn))
                docs = JArray(int)(1)
                freq = JArray(int)(1)
                if termDocs.read(docs, freq) == 1:
                    bits.set(docs[0])

        return bits

    def __str__():

        return "SpecialsFilter"