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///////////////////////////////////////////////////////////////////////////////
//Copyright (C) 2014 Joliciel Informatique
//
//This file is part of Talismane.
//
//Talismane is free software: you can redistribute it and/or modify
//it under the terms of the GNU Affero General Public License as published by
//the Free Software Foundation, either version 3 of the License, or
//(at your option) any later version.
//
//Talismane is distributed in the hope that it will be useful,
//but WITHOUT ANY WARRANTY; without even the implied warranty of
//MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//GNU Affero General Public License for more details.
//
//You should have received a copy of the GNU Affero General Public License
//along with Talismane.  If not, see .
//////////////////////////////////////////////////////////////////////////////
package com.joliciel.talismane.machineLearning.maxent;

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

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.joliciel.talismane.TalismaneException;
import com.joliciel.talismane.machineLearning.ClassificationEvent;
import com.joliciel.talismane.machineLearning.ClassificationEventStream;

import opennlp.model.Event;
import opennlp.model.EventStream;

/**
 * A wrapper for a Talismane CorpusEventStream to make it compatible with
 * OpenNLP Maxent.
 * 
 * @author Assaf Urieli
 *
 */
class OpenNLPEventStream implements EventStream {
  private static final Logger LOG = LoggerFactory.getLogger(OpenNLPEventStream.class);
  private ClassificationEventStream corpusEventStream;

  public OpenNLPEventStream(ClassificationEventStream corpusEventStream) {
    super();
    this.corpusEventStream = corpusEventStream;
  }

  @Override
  public Event next() throws IOException {
    try {
      Event event = null;
      if (this.corpusEventStream.hasNext()) {
        ClassificationEvent corpusEvent = this.corpusEventStream.next();

        List contextList = new ArrayList();
        List weightList = new ArrayList();
        OpenNLPDecisionMaker.prepareData(corpusEvent.getFeatureResults(), contextList, weightList);

        String[] contexts = new String[contextList.size()];
        float[] weights = new float[weightList.size()];

        int i = 0;
        for (String context : contextList) {
          contexts[i++] = context;
        }
        i = 0;
        for (Float weight : weightList) {
          weights[i++] = weight;
        }

        event = new Event(corpusEvent.getClassification(), contexts, weights);
      }
      return event;
    } catch (TalismaneException e) {
      LOG.error(e.getMessage(), e);
      throw new RuntimeException(e);
    }
  }

  @Override
  public boolean hasNext() throws IOException {
    try {
      return this.corpusEventStream.hasNext();
    } catch (TalismaneException e) {
      LOG.error(e.getMessage(), e);
      throw new RuntimeException(e);
    }
  }

}