Lemmatization java [closed]

The Stanford CoreNLP Java library contains a lemmatizer that is a little resource intensive but I have run it on my laptop with <512MB of RAM.

To use it:

1. Download the jar files;
2. Create a new project in your editor of choice/make an ant script that includes all of the jar files contained in the archive you just downloaded;
3. Create a new Java as shown below (based upon the snippet from Stanford’s site);

import java.util.Properties;

public class StanfordLemmatizer {

    protected StanfordCoreNLP pipeline;

    public StanfordLemmatizer() {
        // Create StanfordCoreNLP object properties, with POS tagging
        // (required for lemmatization), and lemmatization
        Properties props;
        props = new Properties();
        props.put("annotators", "tokenize, ssplit, pos, lemma");

        // StanfordCoreNLP loads a lot of models, so you probably
        // only want to do this once per execution
        this.pipeline = new StanfordCoreNLP(props);
    }

    public List<String> lemmatize(String documentText)
    {
        List<String> lemmas = new LinkedList<String>();

        // create an empty Annotation just with the given text
        Annotation document = new Annotation(documentText);

        // run all Annotators on this text
        this.pipeline.annotate(document);

        // Iterate over all of the sentences found
        List<CoreMap> sentences = document.get(SentencesAnnotation.class);
        for(CoreMap sentence: sentences) {
            // Iterate over all tokens in a sentence
            for (CoreLabel token: sentence.get(TokensAnnotation.class)) {
                // Retrieve and add the lemma for each word into the list of lemmas
                lemmas.add(token.get(LemmaAnnotation.class));
            }
        }

        return lemmas;
    }
}