Version.java

/*
 * Copyright (C) 2014 eccentric_nz
 *
 * This program 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.
 *
 * This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
 */
package me.eccentric_nz.TARDIS.utility;

/**
 * Class to compare version strings. Borrowed from StackOverflow.
 *
 * @author alex http://stackoverflow.com/users/1445568/alex
 */
public class Version implements Comparable<Version> {

    private String version;

    public Version(String version) {
        if (version == null) {
            throw new IllegalArgumentException("Version can not be null");
        }
        if (!version.matches("[0-9]+(\\.[0-9]+)*")) {
            throw new IllegalArgumentException("Invalid version format");
        }
        this.version = version;
    }

    public String get() {
        return this.version;
    }

    @Override
    public int compareTo(Version that) {
        if (that == null) {
            return 1;
        }
        String[] thisParts = this.get().split("\\.");
        String[] thatParts = that.get().split("\\.");
        int length = Math.max(thisParts.length, thatParts.length);
        for (int i = 0; i < length; i++) {
            int thisPart = i < thisParts.length
                    ? Integer.parseInt(thisParts[i]) : 0;
            int thatPart = i < thatParts.length
                    ? Integer.parseInt(thatParts[i]) : 0;
            if (thisPart < thatPart) {
                return -1;
            }
            if (thisPart > thatPart) {
                return 1;
            }
        }
        return 0;
    }

    @Override
    public boolean equals(Object that) {
        if (this == that) {
            return true;
        }
        if (that == null) {
            return false;
        }
        if (this.getClass() != that.getClass()) {
            return false;
        }
        return this.compareTo((Version) that) == 0;
    }

    @Override
    public int hashCode() {
        int hash = 3;
        return hash;
    }
}