/*

 * Copyright (c) 1996, 2006, 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 sun.security.acl;

import java.util.*;

import java.security.*;

import java.security.acl.*;

/**

 * Class implementing the Owner interface. The

 * initial owner principal is configured as

 * part of the constructor.

 * @author      Satish Dharmaraj

 */

public class OwnerImpl implements Owner {

    private Group ownerGroup;

    public OwnerImpl(Principal owner) {

        ownerGroup = new GroupImpl("AclOwners");

        ownerGroup.addMember(owner);

    }

    /**

     * Adds an owner. Owners can modify ACL contents and can disassociate

     * ACLs from the objects they protect in the AclConfig interface.

     * The caller principal must be a part of the owners list of the ACL in

     * order to invoke this method. The initial owner is configured

     * at ACL construction time.

     * @param caller the principal who is invoking this method.

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

     * @return true if success, false if already an owner.

     * @exception NotOwnerException if the caller principal is not on

     * the owners list of the Acl.

     */

    public synchronized boolean addOwner(Principal caller, Principal owner)

      throws NotOwnerException

    {

        if (!isOwner(caller))

            throw new NotOwnerException();

        ownerGroup.addMember(owner);

        return false;

    }

    /**

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

     * raised.

     * The caller principal must be a part of the owners list of the ACL in

     * order to invoke this method.

     * @param caller the principal who is invoking this method.

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

     * @return true if the owner is removed, false if the owner is not part

     * of the owners list.

     * @exception NotOwnerException if the caller principal is not on

     * the owners list of the Acl.

     * @exception LastOwnerException if there is only one owner left in the group, then

     * deleteOwner would leave the ACL owner-less. This exception is raised in such a case.

     */

    public synchronized boolean deleteOwner(Principal caller, Principal owner)

      throws NotOwnerException, LastOwnerException

    {

        if (!isOwner(caller))

            throw new NotOwnerException();

        Enumeration<? extends Principal> e = ownerGroup.members();

        //

        // check if there is atleast 2 members left.

        //

        Object o = e.nextElement();

        if (e.hasMoreElements())

            return ownerGroup.removeMember(owner);

        else

            throw new LastOwnerException();

    }

    /**

     * returns if the given principal belongs to the owner list.

     * @param owner The owner to check if part of the owners list

     * @return true if the passed principal is in the owner list, false if not.

     */

    public synchronized boolean isOwner(Principal owner) {

        return ownerGroup.isMember(owner);

    }

}