/*
 * 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 opennlp.tools.formats.convert;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import opennlp.tools.commons.Internal;
import opennlp.tools.parser.Parse;
import opennlp.tools.postag.POSSample;
import opennlp.tools.util.FilterObjectStream;
import opennlp.tools.util.ObjectStream;

/**
 * <b>Note:</b>
 * Do not use this class, internal use only!
 */
@Internal
public class ParseToPOSSampleStream extends FilterObjectStream<Parse, POSSample>  {

  /**
   * Initializes a {@link ParseToPOSSampleStream}.
   *
   * @param samples The {@link ObjectStream<Parse> samples} as input. Must not be {@code null}.
   *
   * @throws IllegalArgumentException Thrown if parameters are invalid.
   */
  public ParseToPOSSampleStream(ObjectStream<Parse> samples) {
    super(samples);
  }

  @Override
  public POSSample read() throws IOException {

    Parse parse = samples.read();

    if (parse != null) {

      List<String> sentence = new ArrayList<>();
      List<String> tags = new ArrayList<>();

      for (Parse tagNode : parse.getTagNodes()) {
        sentence.add(tagNode.getCoveredText());
        tags.add(tagNode.getType());
      }

      return new POSSample(sentence, tags);
    }
    else {
      return null;
    }
  }
}
