/*
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *  under the License.
 */
package org.apache.karaf.jaas.boot.principal;

import java.security.Principal;
import java.util.Enumeration;

public interface Group extends Principal {

    /**
     * Adds the specified member to the group.
     *
     * @param user the principal to add to this group.
     *
     * @return true if the member was successfully added,
     * false if the principal was already a member.
     */
    boolean addMember(Principal user);

    /**
     * Removes the specified member from the group.
     *
     * @param user the principal to remove from this group.
     *
     * @return true if the principal was removed, or
     * false if the principal was not a member.
     */
    boolean removeMember(Principal user);

    /**
     * Returns true if the passed principal is a member of the group.
     * This method does a recursive search, so if a principal belongs to a
     * group which is a member of this group, true is returned.
     *
     * @param member the principal whose membership is to be checked.
     *
     * @return true if the principal is a member of this group,
     * false otherwise.
     */
    boolean isMember(Principal member);


    /**
     * Returns an enumeration of the members in the group.
     * The returned objects can be instances of either Principal
     * or Group (which is a subclass of Principal).
     *
     * @return an enumeration of the group members.
     */
    Enumeration<? extends Principal> members();

}
