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/*
 * 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 chalk.tools.chunker;

import java.io.IOException;

import chalk.tools.util.InvalidFormatException;
import chalk.tools.util.ObjectStream;
import chalk.tools.util.TrainingParameters;
import chalk.tools.util.eval.CrossValidationPartitioner;
import chalk.tools.util.eval.FMeasure;
import chalk.tools.util.model.ModelUtil;


public class ChunkerCrossValidator {

  private final String languageCode;
  private final TrainingParameters params;

  private FMeasure fmeasure = new FMeasure();
  private ChunkerEvaluationMonitor[] listeners;
  private ChunkerFactory chunkerFactory;

  /**
   * @deprecated Use
   *             {@link #ChunkerCrossValidator(String, TrainingParameters, ChunkerFactory, ChunkerEvaluationMonitor...)}
   *             instead.
   */
  @Deprecated
  public ChunkerCrossValidator(String languageCode, int cutoff, int iterations) {

    this.languageCode = languageCode;

    params = ModelUtil.createTrainingParameters(iterations, cutoff);
    listeners = null;
  }

  /**
   * @deprecated Use {@link #ChunkerCrossValidator(String, TrainingParameters, ChunkerFactory, ChunkerEvaluationMonitor...)} instead. 
   */
  public ChunkerCrossValidator(String languageCode, TrainingParameters params,
      ChunkerEvaluationMonitor... listeners) {

    this.languageCode = languageCode;
    this.params = params;
    this.listeners = listeners;
  }
  
  public ChunkerCrossValidator(String languageCode, TrainingParameters params,
      ChunkerFactory factory, ChunkerEvaluationMonitor... listeners) {
    this.chunkerFactory = factory;
    this.languageCode = languageCode;
    this.params = params;
    this.listeners = listeners;
  }

  /**
   * Starts the evaluation.
   * 
   * @param samples
   *          the data to train and test
   * @param nFolds
   *          number of folds
   * 
   * @throws IOException
   */
  public void evaluate(ObjectStream samples, int nFolds)
      throws IOException, InvalidFormatException, IOException {
    CrossValidationPartitioner partitioner = new CrossValidationPartitioner(
        samples, nFolds);

    while (partitioner.hasNext()) {

      CrossValidationPartitioner.TrainingSampleStream trainingSampleStream = partitioner
          .next();

      ChunkerModel model = ChunkerME.train(languageCode, trainingSampleStream,
          params, chunkerFactory);

      // do testing
      ChunkerEvaluator evaluator = new ChunkerEvaluator(new ChunkerME(model,
          ChunkerME.DEFAULT_BEAM_SIZE), listeners);

      evaluator.evaluate(trainingSampleStream.getTestSampleStream());

      fmeasure.mergeInto(evaluator.getFMeasure());
    }
  }

  public FMeasure getFMeasure() {
    return fmeasure;
  }
}