How can I create my own TokenFilter in PyLucene inherited from PythonTokenFilter

[王聃]

everyone:

I'm developing my own Analyzer in PyLucene 4.9.0 and created a TokenFilter for CompoundTokenFilter for compound word splitting in the analyzer as the DictionaryCompoundWordTokenFilter not performing very well.

DictionaryCompoundWordTokenFilter uses a brute algorithm, but I'd like to split compound words only when the subwords in the compound word are all in the dictionary, like "breastcancer" is split when "breast" and "cancer" are both in the given dictionary.

Actually the whole code is based on CompoundWordTokenFilterBase and I just edited the docompose() method in DictionaryCompoundWordTokenFilter class. But when running the program, it show that "the attribute 'length' of 'CharTermAttribute' objects is not readable", and I cannot find what's wrong with it.
And I've searched for how to inherit java classes in pylucene with jcc, but cannot work it out, could someone share some experiences or give some help? Thanks!
from __future__ import division
import lucene, math, itertools

from java.lang importCharSequencefrom java.io importIOExceptionfrom java.util importLinkedListfrom org.apache.pylucene.analysis importPythonTokenStreamfrom org.apache.lucene.analysis importTokenFilterfrom org.apache.pylucene.analysis importPythonTokenFilterfrom org.apache.lucene.analysis importTokenStreamfrom org.apache.lucene.analysis.tokenattributes importCharTermAttributefrom org.apache.lucene.analysis.tokenattributes importOffsetAttributefrom org.apache.lucene.analysis.tokenattributes importPositionIncrementAttributefrom org.apache.lucene.analysis.util importCharArraySetfrom org.apache.lucene.util importAttributeSourcefrom org.apache.lucene.util importVersionclassCompoundTokenFilter(PythonTokenFilter):def __init__(self,matchVersion,input,dictionary,DEFAULT_MIN_WORD_SIZE,DEFAULT_MIN_SUBWORD_SIZE,DEFAULT_MAX_SUBWORD_SIZE):super(CompoundTokenFilter,self).__init__(input)self.matchVersion=matchVersion
self.dictionary=dictionary
self.tokens=LinkedList()self.minWordSize=DEFAULT_MIN_WORD_SIZE
self.minSubwordSize=DEFAULT_MIN_SUBWORD_SIZE
self.maxSubwordSize=DEFAULT_MAX_SUBWORD_SIZE
self.current=AttributeSource.Stateself.termAtt=input.addAttribute(CharTermAttribute.class_)self.offsetAtt=input.addAttribute(OffsetAttribute.class_)self.posIncAtt=input.addAttribute(PositionIncrementAttribute.class_)self.input=input

def decompose(self):
l=self.termAtt.length()
s=self.termAtt.subSequence(0,l)if s inself.dictionary:self.tokens.add(CompoundToken(self.matchVersion,self.input,self.dictionary,self.minWordSize,self.minSubwordSize,self.maxSubwordSize,0,l))else:

d=filter(lambda x:len(x)>=self.minSubwordSize and len(x)<=self.maxSubwordSize in s,this.dictionary)if len(d)>0:
start=int(math.floor(l/self.maxSubwordSize))end=int(math.ceil(l/self.minSubwordSize))
subwords_combinations=[]for i in xrange(start,end+1):
subwords_combinations.extend(itertools.permutations(d,i))
subwords_combinations=filter(lambda x:''.join(x)==s,subwords_combinations)
subwords=sorted(set(reduce(lambda x,y:x+y,subwords_combinations)),key=lambda x:-1*len(x))for subword in subwords:
tokens.add(CompoundToken(self.matchVersion,self.input,self.dictionary,self.minWordSize,self.minSubwordSize,self.maxSubwordSize,s.find(subword),s.find(subword)+len(subword)))def incrementToken(self):if(notself.tokens.isEmpty()):assertself.current!=None
token=self.tokens.removeFirst()AttributeSource.restoreState(self.current)self.termAtt.setEmpty().append(token.txt)self.offsetAttribute.setOffset(token.startOffset, token.endOffset)self.posIncAtt.setPositionIncrement(0)returnTrueself.current=Noneif(self.input.incrementToken()):ifself.termAtt.length()>=self.minWordSize:
decompose()ifnot tokens.isEmpty():self.current=AttributeSource.captureState()returnTrueelse:returnFalsedef reset(self):super(CompoundTokenFilter,self).reset()self.tokens.clear()self.current=NoneclassCompoundToken:def __init__(self,matchVersion,input,dictionary,DEFAULT_MIN_WORD_SIZE,DEFAULT_MIN_SUBWORD_SIZE,DEFAULT_MAX_SUBWORD_SIZE,offset,length):
compoundTokenFilter=CompoundTokenFilter(matchVersion,input,dictionary,DEFAULT_MIN_WORD_SIZE,DEFAULT_MIN_SUBWORD_SIZE,DEFAULT_MAX_SUBWORD_SIZE)self.txt=compoundTokenFilter.termAtt.subSequence(offset, offset + length)

startOff = compoundWordTokenFilterBase.this.offsetAtt.startOffset()
endOff = compoundWordTokenFilterBase.this.offsetAtt.endOffset()if matchVersion.onOrAfter(Version.LUCENE_4_4)or endOff - startOff != compoundTokenFilter.termAtt.length():self.startOffset = startOff
self.endOffset = endOff
else:
newStart = startOff + offset
self.startOffset = newStart
self.endOffset = newStart + length

[Andi Vajda]

Post by 王聃
I'm developing my own Analyzer in PyLucene 4.9.0 and created a TokenFilter for CompoundTokenFilter for compound word splitting in the analyzer as the DictionaryCompoundWordTokenFilter not performing very well.
DictionaryCompoundWordTokenFilter uses a brute algorithm, but I'd like to split compound words only when the subwords in the compound word are all in the dictionary, like "breastcancer" is split when "breast" and "cancer" are both in the given dictionary.
Actually the whole code is based on CompoundWordTokenFilterBase and I just edited the docompose() method in DictionaryCompoundWordTokenFilter class. But when running the program, it show that "the attribute 'length' of 'CharTermAttribute' objects is not readable", and I cannot find what's wrong with it.
And I've searched for how to inherit java classes in pylucene with jcc, but cannot work it out, could someone share some experiences or give some help? Thanks!
from __future__ import division
import lucene, math, itertools
from java.lang importCharSequencefrom java.io importIOExceptionfrom java.util importLinkedListfrom org.apache.pylucene.analysis importPythonTokenStreamfrom org.apache.lucene.analysis importTokenFilterfrom org.apache.pylucene.analysis importPythonTokenFilterfrom org.apache.lucene.analysis importTokenStreamfrom org.apache.lucene.analysis.tokenattributes importCharTermAttributefrom org.apache.lucene.analysis.tokenattributes importOffsetAttributefrom org.apache.lucene.analysis.tokenattributes importPositionIncrementAttributefrom org.apache.lucene.analysis.util importCharArraySetfrom org.apache.lucene.util importAttributeSourcefrom org.apache.lucene.util importVersionclassCompoundTokenFilter(PythonTokenFilter):def __init__(self,matchVersion,input,dictionary,DEFAULT_MIN_WORD_SIZE,DEFAULT_MIN_SUBWORD_SIZE,DEFAULT_MAX_SUBWORD_SIZE):super(CompoundTokenFilter,self).__init__(input)self.matchVersion=matchVersion
self.dictionary=dictionary
self.tokens=LinkedList()self.minWordSize=DEFAULT_MIN_WORD_SIZE
self.minSubwordSize=DEFAULT_MIN_SUBWORD_SIZE
self.maxSubwordSize=DEFAULT_MAX_SUBWORD_SIZE
self.current=AttributeSource.Stateself.termAtt=input.addAttribute(CharTermAttribute.class_)self.offsetAtt=input.addAttribute(OffsetAttribute.class_)self.posIncAtt=input.addAttribute(PositionIncrementAttribute.class_)self.input=input
l=self.termAtt.length()
start=int(math.floor(l/self.maxSubwordSize))end=int(math.ceil(l/self.minSubwordSize))
subwords_combinations.extend(itertools.permutations(d,i))
subwords_combinations=filter(lambda x:''.join(x)==s,subwords_combinations)
tokens.add(CompoundToken(self.matchVersion,self.input,self.dictionary,self.minWordSize,self.minSubwordSize,self.maxSubwordSize,s.find(subword),s.find(subword)+len(subword)))def incrementToken(self):if(notself.tokens.isEmpty()):assertself.current!=None
compoundTokenFilter=CompoundTokenFilter(matchVersion,input,dictionary,DEFAULT_MIN_WORD_SIZE,DEFAULT_MIN_SUBWORD_SIZE,DEFAULT_MAX_SUBWORD_SIZE)self.txt=compoundTokenFilter.termAtt.subSequence(offset, offset + length)
startOff = compoundWordTokenFilterBase.this.offsetAtt.startOffset()
endOff = compoundWordTokenFilterBase.this.offsetAtt.endOffset()if matchVersion.onOrAfter(Version.LUCENE_4_4)or endOff - startOff != compoundTokenFilter.termAtt.length():self.startOffset = startOff
self.endOffset = endOff
newStart = startOff + offset
self.startOffset = newStart
self.endOffset = newStart + length

I don't know enough about the particular API you're trying to use to be of
much help. You might want to try this in Java first and ask on
java-***@lucene.apache.org.

About writing a python extension of a Lucene class, there are a couple of
examples in the PyLucene tests that should be helpful.
$ cd test
$ grep -l Python *.py

Andi..