cc.factorie.app.nlp.ner.NERChunkAnnotator.scala Maven / Gradle / Ivy

/* Copyright (C) 2008-2016 University of Massachusetts Amherst.
   This file is part of "FACTORIE" (Factor graphs, Imperative, Extensible)
   http://factorie.cs.umass.edu, http://github.com/factorie
   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. */
package cc.factorie.app.nlp.ner

import cc.factorie.app.nlp.{Section, Token, Document, DocumentAnnotator}
import scala.reflect.{ClassTag, classTag}
import scala.collection.mutable

import java.util.logging.{Logger, Level}

/**
 * @author John Sullivan
 */
object BilouConllNerChunkAnnotator extends NerChunkAnnotator[ConllNerSpan, BilouConllNerTag]({() => new ConllNerSpanBuffer}, {(s:Section, start:Int, end:Int, cat:String) => new ConllNerSpan(s, start, end, cat)})
object BilouOntonotesNerChunkAnnotator extends NerChunkAnnotator[OntonotesNerSpan, BilouOntonotesNerTag]({() => new OntonotesNerSpanBuffer}, {(s:Section, start:Int, end:Int, cat:String) => new OntonotesNerSpan(s, start, end, cat)})
object BioConllNerChunkAnnotator extends NerChunkAnnotator[ConllNerSpan, BioConllNerTag]({() => new ConllNerSpanBuffer}, {(s:Section, start:Int, end:Int, cat:String) => new ConllNerSpan(s, start, end, cat)})
object BioOntonotesNerChunkAnnotator extends NerChunkAnnotator[OntonotesNerSpan, BioOntonotesNerTag]({() => new OntonotesNerSpanBuffer}, {(s:Section, start:Int, end:Int, cat:String) => new OntonotesNerSpan(s, start, end, cat)})

/** Takes documents that are already annotated with token-level NerTags of type Tag and annotates them with NerSpans
  * of type Span */
class NerChunkAnnotator[Span <: NerSpan : ClassTag, Tag <: NerTag : ClassTag](newBuffer:() => NerSpanBuffer[Span], newSpan:(Section, Int, Int, String) => Span) extends DocumentAnnotator {

  val prereqAttrs = Seq(classTag[Tag].runtimeClass)
  val postAttrs = Seq(classTag[Span].runtimeClass)

  def tokenAnnotationString(token: Token) = token.attr.exactly[Tag].categoryValue

  def process(doc: Document) = {
    sealed trait State
    case class Reading(tag:String) extends State
    case object NotReading extends State

    val spanBuffer = newBuffer()
    doc.sections.foreach { sec =>
      val iter = sec.tokens.iterator
      var tok:Token = null
      var state:State = NotReading
      val tokBuffer = mutable.ArrayBuffer[Token]()
      while(iter.hasNext) {
        tok = iter.next()
        val tag = tok.attr[Tag]
        (tag.spanPrefix, state) match {
          case ("O", NotReading) => ()
          case ("U", NotReading) => spanBuffer.add(newSpan(sec, tok.positionInSection, 1, tag.baseCategoryValue))(null)
          case ("B", NotReading) =>
            tokBuffer += tok
            state = Reading(tag.baseCategoryValue)
          case ("I", Reading(_)) =>
            tokBuffer += tok
          case ("O", Reading(t)) =>
            spanBuffer.add(newSpan(sec, tokBuffer.head.positionInSection, tokBuffer.size, t))(null)
            tokBuffer.clear()
            state = NotReading
          case ("L", Reading(t)) =>
            tokBuffer += tok
            spanBuffer.add(newSpan(sec, tokBuffer.head.positionInSection, tokBuffer.size, t))(null)
            tokBuffer.clear()
            state = NotReading
          case (prefix, s) =>
            val prevStr = {
              val prevToken = if (tok.hasPrev) tok.prev else null
              if (prevToken != null) prevToken.attr[Tag].categoryValue else ""
            }
            NerChunkAnnotator.logger.log(Level.FINE, "Invalid combination of states, prefix %s, state %s at token %s. Previous token was %s.".format(prefix, s, tok, prevStr))
        }
      }
      if (tokBuffer.nonEmpty) {
        spanBuffer.add(newSpan(sec, tokBuffer.head.positionInSection, tokBuffer.size, state.asInstanceOf[Reading].tag))(null)
      }
    }
    doc.attr += spanBuffer
    doc.annotators ++= Seq(classTag[Tag].runtimeClass -> this.getClass, classTag[NerSpanBuffer[Span]].runtimeClass -> this.getClass)
    doc
  }
}

object NerChunkAnnotator {
    private val logger : Logger = Logger.getLogger(getClass.getName)
}