# ====================================================================
# 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 Token,PythonTokenFilter,TermAttribute
from lia.analysis.AnalyzerUtils import AnalyzerUtils
#
# A TokenFilter extension
#
class SynonymFilter(PythonTokenFilter):
TOKEN_TYPE_SYNONYM = "SYNONYM"
def __init__(self, inStream, engine):
super(SynonymFilter, self).__init__(inStream)
self.synonymStack = []
self.termAttr = self.addAttribute(TermAttribute.class_)
self.save = inStream.cloneAttributes()
self.engine = engine
self.inStream = inStream
def incrementToken(self):
if len(self.synonymStack) > 0:
syn = self.synonymStack.pop()
self.restoreState(syn)
return True
if not self.inStream.incrementToken():
return False
self.addAliasesToStack()
return True
def addAliasesToStack(self):
synonyms = self.engine.getSynonyms(self.termAttr.term())
if synonyms is None:
return
current = self.captureState()
for synonym in synonyms:
self.save.restoreState(current)
AnalyzerUtils.setTerm(self.save, synonym)
AnalyzerUtils.setType(self.save, self.TOKEN_TYPE_SYNONYM)
AnalyzerUtils.setPositionIncrement(self.save, 0)
self.synonymStack.append(self.save.captureState())
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