001/*
002 * Copyright 2002-2018 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.web.servlet;
018
019import java.util.Locale;
020
021import org.springframework.lang.Nullable;
022
023/**
024 * Interface to be implemented by objects that can resolve views by name.
025 *
026 * <p>View state doesn't change during the running of the application,
027 * so implementations are free to cache views.
028 *
029 * <p>Implementations are encouraged to support internationalization,
030 * i.e. localized view resolution.
031 *
032 * @author Rod Johnson
033 * @author Juergen Hoeller
034 * @see org.springframework.web.servlet.view.InternalResourceViewResolver
035 * @see org.springframework.web.servlet.view.ResourceBundleViewResolver
036 * @see org.springframework.web.servlet.view.XmlViewResolver
037 */
038public interface ViewResolver {
039
040        /**
041         * Resolve the given view by name.
042         * <p>Note: To allow for ViewResolver chaining, a ViewResolver should
043         * return {@code null} if a view with the given name is not defined in it.
044         * However, this is not required: Some ViewResolvers will always attempt
045         * to build View objects with the given name, unable to return {@code null}
046         * (rather throwing an exception when View creation failed).
047         * @param viewName name of the view to resolve
048         * @param locale the Locale in which to resolve the view.
049         * ViewResolvers that support internationalization should respect this.
050         * @return the View object, or {@code null} if not found
051         * (optional, to allow for ViewResolver chaining)
052         * @throws Exception if the view cannot be resolved
053         * (typically in case of problems creating an actual View object)
054         */
055        @Nullable
056        View resolveViewName(String viewName, Locale locale) throws Exception;
057
058}