001/**
002 * Copyright 2005-2015 The Kuali Foundation
003 *
004 * Licensed under the Educational Community License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.opensource.org/licenses/ecl2.php
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016package org.kuali.rice.kew.api.identity;
017
018import java.io.Serializable;
019
020/**
021 * Superinterface of UserId and GroupId
022 * @author Kuali Rice Team (rice.collab@kuali.org)
023 */
024public interface Id extends Serializable {
025    /**
026     * Returns true if this Id has an empty value. Empty Ids can't be used as keys in a Hash,
027     * among other things.
028     *
029     * @return true if this instance doesn't have a value
030     */
031    public boolean isEmpty();
032}