/*******************************************************************************
 * Copyright 2012 Yuriy Lagodiuk
 * 
 * Licensed 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 com.lagodiuk.ga;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;
import java.util.Random;

public class Population> implements Iterable {

	private static final int DEFAULT_NUMBER_OF_CHROMOSOMES = 32;

	private List chromosomes = new ArrayList(DEFAULT_NUMBER_OF_CHROMOSOMES);

	private final Random random = new Random();

	public void addChromosome(C chromosome) {
		this.chromosomes.add(chromosome);
	}

	public int getSize() {
		return this.chromosomes.size();
	}

	public C getRandomChromosome() {
		int numOfChromosomes = this.chromosomes.size();
		// TODO improve random generator
		// maybe use pattern strategy ?
		int indx = this.random.nextInt(numOfChromosomes);
		return this.chromosomes.get(indx);
	}

	public C getChromosomeByIndex(int indx) {
		return this.chromosomes.get(indx);
	}

	public void sortPopulationByFitness(Comparator chromosomesComparator) {
		Collections.shuffle(this.chromosomes);
		Collections.sort(this.chromosomes, chromosomesComparator);
	}

	/**
	 * shortening population till specific number
	 */
	public void trim(int len) {
		this.chromosomes = this.chromosomes.subList(0, len);
	}

	@Override
	public Iterator iterator() {
		return this.chromosomes.iterator();
	}

}