/*

 * Copyright (c) 1997, 2007, Oracle and/or its affiliates. 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.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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package com.sun.jmx.snmp.IPAcl;

import java.util.Vector;

import java.io.Serializable;

import java.security.Principal;

import java.security.acl.Owner;

import java.security.acl.LastOwnerException;

import java.security.acl.NotOwnerException;

/**

 * Owner of Access Control Lists (ACLs).

 * The initial owner Principal should be specified as an

 * argument to the constructor of the class AclImpl.

 *

 * @see java.security.acl.Owner

 */

class OwnerImpl implements Owner, Serializable {

  private static final long serialVersionUID = -576066072046319874L;

  private Vector<Principal> ownerList = null;

  /**

   * Constructs an empty list of owner.

   */

  public OwnerImpl (){

        ownerList = new Vector<Principal>();

  }

  /**

   * Constructs a list of owner with the specified principal as first element.

   *

   * @param owner the principal added to the owner list.

   */

  public OwnerImpl (PrincipalImpl owner){

        ownerList = new Vector<Principal>();

        ownerList.addElement(owner);

  }

  /**

   * Adds an owner. Only owners can modify ACL contents. The caller principal

   * must be an owner of the ACL in order to invoke this method. That is, only

   * an owner can add another owner. The initial owner is configured at

   * ACL construction time.

   *

   * @param caller the principal invoking this method.

   *        It must be an owner of the ACL.

   * @param owner the owner that should be added to the list of owners.

   * @return true if successful, false if owner is already an owner.

   * @exception NotOwnerException if the caller principal is not an owner

   *    of the ACL.

   */

  public boolean addOwner(Principal caller, Principal owner)

        throws NotOwnerException {

        if (!ownerList.contains(caller))

          throw new NotOwnerException();

        if (ownerList.contains(owner)) {

          return false;

        } else {

          ownerList.addElement(owner);

          return true;

        }

  }

  /**

   * Deletes an owner. If this is the last owner in the ACL, an exception is raised.

   *<P>

   * The caller principal must be an owner of the ACL in order to invoke this method.

   *

   * @param caller the principal invoking this method. It must be an owner

   *   of the ACL.

   * @param owner the owner to be removed from the list of owners.

   * @return true if successful, false if owner is already an owner.

   * @exception NotOwnerException if the caller principal is not an owner

   *   of the ACL.

   * @exception LastOwnerException if there is only one owner left, so that

   *   deleteOwner would leave the ACL owner-less.

   */

  public boolean deleteOwner(Principal caller, Principal owner)

                throws NotOwnerException,LastOwnerException {

        if (!ownerList.contains(caller))

          throw new NotOwnerException();

        if (!ownerList.contains(owner)){

          return false;

        } else {

          if (ownerList.size() == 1)

                throw new LastOwnerException();

          ownerList.removeElement(owner);

          return true;

        }

  }

  /**

   * Returns true if the given principal is an owner of the ACL.

   *

   * @param owner the principal to be checked to determine whether or

   *        not it is an owner.

   * @return true if the given principal is an owner of the ACL.

   */

  public boolean isOwner(Principal owner){

        return ownerList.contains(owner);

  }

}