RandomizationAlgorithm.java

/* 
 * (c) 2008- RANDI2 Core Development Team
 * 
 * This file is part of RANDI2.
 * 
 * RANDI2 is free software: you can redistribute it and/or modify it under the
 * terms of the GNU General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later
 * version.
 * 
 * RANDI2 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 General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License along with
 * RANDI2. If not, see <http://www.gnu.org/licenses/>.
 */
package de.randi2.randomization;

import java.util.Random;

import de.randi2.model.TreatmentArm;
import de.randi2.model.Trial;
import de.randi2.model.TrialSubject;
import de.randi2.model.randomization.AbstractRandomizationConfig;

public abstract class RandomizationAlgorithm<Conf extends AbstractRandomizationConfig> {
	protected Trial trial;
	protected Conf configuration;
	private Random seededRandom;
	private long seed = Long.MIN_VALUE;
	
	@SuppressWarnings("unchecked")
	protected RandomizationAlgorithm(Trial _trial) {
		super();
		this.trial = _trial;
		this.configuration = (Conf) trial.getRandomizationConfiguration();
	}

	@SuppressWarnings("unchecked")
	protected RandomizationAlgorithm(Trial _trial, long seed) {
		super();
		this.trial = _trial;
		this.configuration = (Conf) trial.getRandomizationConfiguration();
		this.seed = seed;
		this.seededRandom = new Random(seed);
	}

	/**
	 * Randomizes a trial subject into the treatment arms of the trial. If the
	 * algorithm is not seeded (that is to say, we are in real use and not in
	 * test mode) the subject will be assigned to the treatment by the
	 * randomization. If the algorithm has been seeded, the subjects treatment
	 * property remains unchanged.
	 * 
	 * @param subject
	 *            The subject to be randomized. The treatment arm will be
	 *            assigned, unless the algorithm is seeded.
	 * @return The randomized treatment arm.
	 */
	public TreatmentArm randomize(TrialSubject subject) {
		// Actual Randomization
		TreatmentArm assignedArm = doRadomize(subject, getRandom());

		// Work after
		return assignedArm;
	}

	protected abstract TreatmentArm doRadomize(TrialSubject subject,
			Random random);
		
	public long getSeed(){
		return seed;
	}

	public boolean isSeeded() {
		return seededRandom != null;
	}

	private Random getRandom() {
		if (isSeeded()) {
			return seededRandom;
		} else {
			return new Random();
		}
	}
}