RangeSeq.java

/*
 * Vitry, copyright (C) Hans Hoglund 2011
 * 
 * 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/>.
 *
 * See COPYING.txt for details.
 */
package vitry.runtime.struct;

import java.math.BigInteger;


public class RangeSeq extends AbstractSeq<BigInteger>
{
    private final BigInteger min;
    private final BigInteger last;

    private RangeSeq(BigInteger min, BigInteger last) {
        this.min = min;
        this.last = last;
    }
    
    public static RangeSeq create(BigInteger min, BigInteger max)
    {
        return new RangeSeq(min, max.subtract(BigInteger.ONE));
    }

    public BigInteger head()
    {
        return min;
    }

    public Seq<BigInteger> tail()
    {
        if (!hasTail())
            return null;
        else
            return new RangeSeq(min.add(BigInteger.ONE), last);
    }

    public boolean hasTail()
    {
        return last.compareTo(min) > 0;
    }
}