Country.java

/*
 * Copyright 2007 Zhang, Zheng <oldbig@gmail.com>
 * 
 * This file is part of ZOJ.
 * 
 * ZOJ 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 revision 3 of the License, or (at your option) any later revision.
 * 
 * ZOJ 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 ZOJ. if not, see
 * <http://www.gnu.org/licenses/>.
 */

package cn.edu.zju.acm.onlinejudge.bean.enumeration;

/**
 * <p>
 * This class represents the Country. It has two attributes: id, name.
 * </p>
 * 
 * @author Zhang, Zheng
 * @version 2.0
 */
public class Country {

    /**
     * <p>
     * Represents the id of the country. It is initialize in constructor.
     * </p>
     */
    private long id;

    /**
     * <p>
     * Represents the name of the country. It is initialize in constructor.
     * </p>
     */
    private String name;

    /**
     * <p>
     * Constructs a new instance.
     * </p>
     * 
     * @param id
     *            the id of the country.
     * @param name
     *            the name of the country.
     * 
     * @throws NullPointerException
     *             if the name argument is null.
     * @throws IllegalArgumentException
     *             if the name is an empty string.
     */
    public Country(long id, String name) {
        if (name == null) {
            throw new NullPointerException("name should not be null.");
        }
        if (name.trim().length() == 0) {
            throw new IllegalArgumentException("name should not be empty string.");
        }
        this.id = id;
        this.name = name;
    }

    /**
     * <p>
     * Get the id of the country.
     * </p>
     * 
     * @return id the id of the country.
     */
    public long getId() {
        return this.id;
    }

    /**
     * <p>
     * Get the name of the country.
     * </p>
     * 
     * @return name the name of the country.
     */
    public String getName() {
        return this.name;
    }

    /**
     * <p>
     * Compares to the object.
     * </p>
     * 
     * @return true if and only if the ids of the two are the same.
     * 
     * @param object
     *            the object to compare.
     */
    @Override
    public boolean equals(Object object) {
        return object instanceof Country && this.id == ((Country) object).id;
    }

    /**
     * <p>
     * get the hashCode of this instance.
     * </p>
     * 
     * @return the hash code of this instance.
     */
    @Override
    public int hashCode() {
        return new Long(this.id).hashCode();
    }

}