/*
 * Copyright (C) 2004 NNL Technology AB
 * Visit www.infonode.net for information about InfoNode(R) 
 * products and how to contact NNL Technology AB.
 *
 * 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 2
 * 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, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, 
 * MA 02111-1307, USA.
 */


// $Id: IntList.java,v 1.3 2004/09/22 14:35:05 jesper Exp $
package net.infonode.util;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;

/**
 * A single linked list of positive int's.
 *
 * @author $Author: jesper $
 * @version $Revision: 1.3 $
 */
public class IntList {
  /**
   * The empty list.
   */
  public static final IntList EMPTY_LIST = new IntList(-1, null);

  private int value;
  private IntList next;

  /**
   * Constructor.
   *
   * @param value the int value
   * @param next  the next list element
   */
  public IntList(int value, IntList next) {
    this.value = value;
    this.next = next;
  }

  /**
   * @return
   */
  public int getValue() {
    return value;
  }

  public IntList getNext() {
    return next;
  }

  public boolean isEmpty() {
    return this == EMPTY_LIST;
  }

  public boolean equals(Object object) {
    return object instanceof IntList && equals((IntList) object);
  }

  public boolean equals(IntList list) {
    return value == list.value && (next == null ? list.next == null : next.equals(list.next));
  }

  public int hashCode() {
    int result = 17;
    result = 37 * result + value;

    if (next != null)
      result = 37 * result + next.hashCode();

    return result;
  }

  public void write(ObjectOutputStream out) throws IOException {
    out.writeInt(value);

    if (next != null)
      next.write(out);
  }

  public static IntList decode(ObjectInputStream in) throws IOException {
    int i = in.readInt();
    return i == -1 ? EMPTY_LIST : new IntList(i, decode(in));
  }

  public String toString() {
    return value + (next == null ? "" : ", " + next.toString());
  }

}