Location.java

package net.java.cargotracker.domain.model.location;

import java.io.Serializable;
import javax.persistence.Embedded;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.NamedQueries;
import javax.persistence.NamedQuery;
import javax.validation.constraints.NotNull;
import org.apache.commons.lang3.Validate;

/**
 * A location in our model is stops on a journey, such as cargo origin or
 * destination, or carrier movement end points.
 *
 * It is uniquely identified by a UN location code.
 */
@Entity
@NamedQueries({
    @NamedQuery(name = "Location.findAll", query = "Select l from Location l"),
    @NamedQuery(name = "Location.findByUnLocode",
            query = "Select l from Location l where l.unLocode = :unLocode")})
public class Location implements Serializable {

    private static final long serialVersionUID = 1L;
    @Id
    @GeneratedValue
    private Long id;
    @Embedded
    private UnLocode unLocode;
    @NotNull
    private String name;
    // Special Location object that marks an unknown location.
    public static final Location UNKNOWN = new Location(new UnLocode("XXXXX"),
            "Unknown location");

    public Location() {
        // Nothing to do.
    }

    /**
     * @param unLocode UN Locode
     * @param name Location name
     * @throws IllegalArgumentException if the UN Locode or name is null
     */
    public Location(UnLocode unLocode, String name) {
        Validate.notNull(unLocode);
        Validate.notNull(name);

        this.unLocode = unLocode;
        this.name = name;
    }

    /**
     * @return UN Locode for this location.
     */
    public UnLocode getUnLocode() {
        return unLocode;
    }

    /**
     * @return Actual name of this location, e.g. "Stockholm".
     */
    public String getName() {
        return name;
    }

    /**
     * @param object to compare
     * @return Since this is an entiy this will be true iff UN locodes are
     * equal.
     */
    @Override
    public boolean equals(Object object) {
        if (object == null) {
            return false;
        }
        if (this == object) {
            return true;
        }
        if (!(object instanceof Location)) {
            return false;
        }
        Location other = (Location) object;
        return sameIdentityAs(other);
    }

    public boolean sameIdentityAs(Location other) {
        return this.unLocode.sameValueAs(other.unLocode);
    }

    /**
     * @return Hash code of UN locode.
     */
    @Override
    public int hashCode() {
        return unLocode.hashCode();
    }

    @Override
    public String toString() {
        return name + " [" + unLocode + "]";
    }
}