001/*
002 * Copyright 2002-2017 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.view;
018
019import java.util.Locale;
020
021import org.springframework.beans.factory.InitializingBean;
022
023/**
024 * Abstract base class for URL-based views. Provides a consistent way of
025 * holding the URL that a View wraps, in the form of a "url" bean property.
026 *
027 * @author Juergen Hoeller
028 * @since 13.12.2003
029 */
030public abstract class AbstractUrlBasedView extends AbstractView implements InitializingBean {
031
032        private String url;
033
034
035        /**
036         * Constructor for use as a bean.
037         */
038        protected AbstractUrlBasedView() {
039        }
040
041        /**
042         * Create a new AbstractUrlBasedView with the given URL.
043         * @param url the URL to forward to
044         */
045        protected AbstractUrlBasedView(String url) {
046                this.url = url;
047        }
048
049
050        /**
051         * Set the URL of the resource that this view wraps.
052         * The URL must be appropriate for the concrete View implementation.
053         */
054        public void setUrl(String url) {
055                this.url = url;
056        }
057
058        /**
059         * Return the URL of the resource that this view wraps.
060         */
061        public String getUrl() {
062                return this.url;
063        }
064
065        @Override
066        public void afterPropertiesSet() throws Exception {
067                if (isUrlRequired() && getUrl() == null) {
068                        throw new IllegalArgumentException("Property 'url' is required");
069                }
070        }
071
072        /**
073         * Return whether the 'url' property is required.
074         * <p>The default implementation returns {@code true}.
075         * This can be overridden in subclasses.
076         */
077        protected boolean isUrlRequired() {
078                return true;
079        }
080
081        /**
082         * Check whether the underlying resource that the configured URL points to
083         * actually exists.
084         * @param locale the desired Locale that we're looking for
085         * @return {@code true} if the resource exists (or is assumed to exist);
086         * {@code false} if we know that it does not exist
087         * @throws Exception if the resource exists but is invalid (e.g. could not be parsed)
088         */
089        public boolean checkResource(Locale locale) throws Exception {
090                return true;
091        }
092
093        @Override
094        public String toString() {
095                return super.toString() + "; URL [" + getUrl() + "]";
096        }
097
098}