net.sourceforge.cilib.problem.AbstractProblem Maven / Gradle / Ivy

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/**           __  __
 *    _____ _/ /_/ /_    Computational Intelligence Library (CIlib)
 *   / ___/ / / / __ \   (c) CIRG @ UP
 *  / /__/ / / / /_/ /   http://cilib.net
 *  \___/_/_/_/_.___/
 */
package net.sourceforge.cilib.problem;

import java.util.concurrent.atomic.AtomicInteger;
import net.sourceforge.cilib.problem.objective.Minimise;
import net.sourceforge.cilib.problem.objective.Objective;
import net.sourceforge.cilib.problem.solution.Fitness;
import net.sourceforge.cilib.type.DomainRegistry;
import net.sourceforge.cilib.type.StringBasedDomainRegistry;
import net.sourceforge.cilib.type.types.Type;

/**
 * This is a convenience class that keeps track of the number of fitness
 * evaluations. This class can be extended instead of implementing
 * {@link Problem} directly.
 * 
 * The contract of returning an instance of
 * {@link net.sourceforge.cilib.problem.solution.InferiorFitness} for solutions
 * outside  the problem search space is implemented by {@link #getFitness(Type)}.
 */
public abstract class AbstractProblem implements Problem {

    private static final long serialVersionUID = -5008516277429476778L;

    protected AtomicInteger fitnessEvaluations;
    protected DomainRegistry domainRegistry;
    protected Objective objective;

    protected AbstractProblem() {
        this.fitnessEvaluations = new AtomicInteger(0);
        this.domainRegistry = new StringBasedDomainRegistry();
        this.objective = new Minimise();
    }

    protected AbstractProblem(AbstractProblem copy) {
        this.fitnessEvaluations = copy.fitnessEvaluations;
        this.domainRegistry = copy.domainRegistry.getClone();
        this.objective = copy.objective;
    }

    @Override
    public abstract AbstractProblem getClone();

    /**
     * Determine the {@code Fitness} of the current {@link Problem} instance
     * based on the provided {@code solution}.
     *
     * @param solution  The {@linkplain Type} representing the candidate solution.
     * @return          The {@linkplain Fitness} of the {@code solution} in the
     *                  current {@linkplain Problem}.
     */
    protected abstract Fitness calculateFitness(Type solution);

    /**
     * {@inheritDoc}
     */
    @Override
    public final Fitness getFitness(Type solution) {
        fitnessEvaluations.incrementAndGet();

        return calculateFitness(solution);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public final int getFitnessEvaluations() {
        return fitnessEvaluations.get();
    }

    @Override
    public DomainRegistry getDomain() {
        if (domainRegistry.getDomainString() == null) {
            throw new IllegalStateException("Domain has not been defined. Please define domain for function optimisation.");
        }
        return domainRegistry;
    }

    @Override
    public void setDomain(String domain) {
        this.domainRegistry.setDomainString(domain);
    }

    public void setObjective(Objective objective) {
        this.objective = objective;
    }

    public Objective getObjective() {
        return objective;
    }
}