/*
 * Copyright 1997-2007 Sun Microsystems, Inc.  All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 */


package com.sun.jmx.snmp.IPAcl;


import java.util.Vector;
import java.util.Enumeration;
import java.io.Serializable;
import java.net.UnknownHostException;


import java.security.Principal;
import java.security.acl.Group;


/**
 * This class is used to represent a subnet mask (a group of hosts
 * matching the same
 * IP mask).
 *
 */

class GroupImpl extends PrincipalImpl implements Group, Serializable {
  private static final long serialVersionUID = -7777387035032541168L;

  /**
   * Constructs an empty group.
   * @exception UnknownHostException Not implemented
   */
  public GroupImpl () throws UnknownHostException {
  }

  /**
   * Constructs a group using the specified subnet mask.
   *
   * @param mask The subnet mask to use to build the group.
   * @exception UnknownHostException if the subnet mask cann't be built.
   */
  public GroupImpl (String mask) throws UnknownHostException {
        super(mask);
  }

    /**
     * Adds the specified member to the group.
     *
     * @param p the principal to add to this group.
     * @return true if the member was successfully added, false if the
     *     principal was already a member.
     */
    public boolean addMember(Principal p) {
        // we don't need to add members because the ip address is a
        // subnet mask
        return true;
    }

  public int hashCode() {
        return super.hashCode();
  }

  /**
   * Compares this group to the specified object. Returns true if the object
   * passed in matches the group represented.
   *
   * @param p the object to compare with.
   * @return true if the object passed in matches the subnet mask,
   *   false otherwise.
   */
  public boolean equals (Object p) {
        if (p instanceof PrincipalImpl || p instanceof GroupImpl){
          if ((super.hashCode() & p.hashCode()) == p.hashCode()) return true;
          else return false;
        } else {
          return false;
        }
  }

  /**
   * Returns true if the passed principal is a member of the group.
   *
   * @param p the principal whose membership is to be checked.
   * @return true if the principal is a member of this group, false otherwise.
   */
  public boolean isMember(Principal p) {
        if ((p.hashCode() & super.hashCode()) == p.hashCode()) return true;
        else return false;
  }

  /**
   * Returns an enumeration which contains the subnet mask.
   *
   * @return an enumeration which contains the subnet mask.
   */
  public Enumeration<? extends Principal> members(){
        Vector<Principal> v = new Vector<Principal>(1);
        v.addElement(this);
        return v.elements();
  }

  /**
   * Removes the specified member from the group. (Not implemented)
   *
   * @param p the principal to remove from this group.
   * @return allways return true.
   */
  public boolean removeMember(Principal p) {
        return true;
  }

  /**
   * Prints a string representation of this group.
   *
   * @return  a string representation of this group.
   */
  public String toString() {
        return ("GroupImpl :"+super.getAddress().toString());
  }
}