001/*
002 * Copyright 2002-2012 the original author or authors.
003 *
004 * Licensed under the Apache 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 *      https://www.apache.org/licenses/LICENSE-2.0
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 */
016
017package org.springframework.ui.context;
018
019import org.springframework.lang.Nullable;
020
021/**
022 * Sub-interface of ThemeSource to be implemented by objects that
023 * can resolve theme messages hierarchically.
024 *
025 * @author Jean-Pierre Pawlak
026 * @author Juergen Hoeller
027 */
028public interface HierarchicalThemeSource extends ThemeSource {
029
030        /**
031         * Set the parent that will be used to try to resolve theme messages
032         * that this object can't resolve.
033         * @param parent the parent ThemeSource that will be used to
034         * resolve messages that this object can't resolve.
035         * May be {@code null}, in which case no further resolution is possible.
036         */
037        void setParentThemeSource(@Nullable ThemeSource parent);
038
039        /**
040         * Return the parent of this ThemeSource, or {@code null} if none.
041         */
042        @Nullable
043        ThemeSource getParentThemeSource();
044
045}