/**
* Label entities in an ExtractionSentence. Assumes the classifier has already been trained.
*
* @param sentence ExtractionSentence that we want to extract entities from
* @return an ExtractionSentence with text content, tree and entities set. Relations will not be
* set.
*/
private CoreMap extractEntities(CoreMap sentence, int sentCount) {
// don't add answer annotations
List<CoreLabel> testSentence =
AnnotationUtils.sentenceEntityMentionsToCoreLabels(
sentence, false, annotationsToSkip, null, useSubTypes, useBIO);
// now label the sentence
List<CoreLabel> annotatedSentence = this.classifier.classify(testSentence);
if (logger.isLoggable(Level.FINEST)) {
logger.finest("CLASSFIER OUTPUT: " + annotatedSentence);
}
List<EntityMention> extractedEntities = new ArrayList<>();
int i = 0;
// variables which keep track of partially seen entities (i.e. we've seen
// some but not all the words in them so far)
String lastType = null;
int startIndex = -1;
//
// note that labels may be in the BIO or just the IO format. we must handle both transparently
//
for (CoreLabel label : annotatedSentence) {
String type = label.get(AnswerAnnotation.class);
if (type.equals(SeqClassifierFlags.DEFAULT_BACKGROUND_SYMBOL)) {
type = null;
}
// this is an entity end boundary followed by O
if (type == null && lastType != null) {
makeEntityMention(sentence, startIndex, i, lastType, extractedEntities, sentCount);
logger.info("Found entity: " + extractedEntities.get(extractedEntities.size() - 1));
startIndex = -1;
}
// entity start preceded by an O
else if (lastType == null && type != null) {
startIndex = i;
}
// entity end followed by another entity of different type
else if (lastType != null
&& type != null
&& (type.startsWith("B-")
|| (lastType.startsWith("I-") && type.startsWith("I-") && !lastType.equals(type))
|| (notBIO(lastType) && notBIO(type) && !lastType.equals(type)))) {
makeEntityMention(sentence, startIndex, i, lastType, extractedEntities, sentCount);
logger.info("Found entity: " + extractedEntities.get(extractedEntities.size() - 1));
startIndex = i;
}
lastType = type;
i++;
}
// replace the original annotation with the predicted entities
sentence.set(MachineReadingAnnotations.EntityMentionsAnnotation.class, extractedEntities);
logger.finest("EXTRACTED ENTITIES: ");
for (EntityMention e : extractedEntities) {
if (logger.isLoggable(Level.FINEST)) {
logger.finest("\t" + e);
}
}
postprocessSentence(sentence, sentCount);
return sentence;
}
