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 * Copyright (c) 2016, David Picard.
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 * 1. Redistributions of source code must retain the above copyright notice, this
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 * may be used to endorse or promote products derived from this software without
 * specific prior written permission.
 *
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package net.jkernelmachines.active;

import java.util.List;

import net.jkernelmachines.classifier.OnlineClassifier;
import net.jkernelmachines.type.TrainingSample;

/**
 * <p>
 * Base abstract class for active learning strategies. 
 * </p>
 * <p>
 * This class contains an instance
 * of a classifier and a training set of samples. The classifier can be updated externaly, 
 * or thanks to helpers present in the class 
 * </p>
 * @author picard
 *
 */
public abstract class ActiveLearner<T> {
		
	protected OnlineClassifier<T> classifier;
	protected List<TrainingSample<T>> train;
	
	/**
	 * Method returning the best training sample in the list with respect to the active strategy
	 * @param l list
	 * @return the best sample
	 */
	public abstract TrainingSample<T> getActiveSample(List<TrainingSample<T>> l);
	
	/**
	 * perform nbSample updates of the classifier using the active strategy
	 * @param nbSamples number of samples
	 */
	public abstract void updateClassifier(int nbSamples);
	
	/**
	 * Setter for the classifier
	 * @param cls classifier
	 */
	public void setClassifier(OnlineClassifier<T> cls) {
		this.classifier = cls;
	}
	
	/**
	 * Getter for the classifier
	 * @return the classifier
	 */
	public OnlineClassifier<T> getClassifier() {
		return this.classifier;
	}

	/**
	 * Return the list of training samples
	 * @return the list of training samples
	 */
	public List<TrainingSample<T>> getTrain() {
		return train;
	}

	/**
	 * Sets the list of training samples
	 * @param train the list of training samples
	 */
	public void setTrain(List<TrainingSample<T>> train) {
		this.train = train;
	}

}
