nlpcraft-stanford/src/main/scala/org/apache/nlpcraft/common/nlp/core/stanford/NCStanfordTokenizer.scala

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.nlpcraft.common.nlp.core.stanford

import java.io.StringReader
import edu.stanford.nlp.process.PTBTokenizer
import io.opencensus.trace.Span
import org.apache.nlpcraft.common.NCService
import org.apache.nlpcraft.common.nlp.core.{NCNlpCoreToken, NCNlpTokenizer}

import scala.jdk.CollectionConverters.ListHasAsScala

/**
  * Stanford tokenizer implementation.
  */
object NCStanfordTokenizer extends NCNlpTokenizer {
    /**
      *
      * @param parent Optional parent span.
      * @return
      */
    override def start(parent: Span = null): NCService = startScopedSpan("start", parent) { _ =>
        ackStarting()
        ackStarted()
    }

    /**
      *
      * @param parent Optional parent span.
      */
    override def stop(parent: Span = null): Unit = startScopedSpan("stop", parent) { _ =>
        ackStopping()
        ackStopped()
    }

    override def tokenize(sen: String): Seq[NCNlpCoreToken] = {
        PTBTokenizer.newPTBTokenizer(new StringReader(sen)).
            tokenize().
            asScala.
            map(p => NCNlpCoreToken(p.word(), p.beginPosition(), p.endPosition(), p.endPosition() - p.beginPosition()))
    }
}