001/*
002 * Copyright 2002-2019 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.handler;
018
019import java.util.Collections;
020import java.util.List;
021import javax.servlet.http.HttpServletRequest;
022import javax.servlet.http.HttpServletResponse;
023
024import org.springframework.core.Ordered;
025import org.springframework.web.servlet.HandlerExceptionResolver;
026import org.springframework.web.servlet.ModelAndView;
027
028/**
029 * A {@link HandlerExceptionResolver} that delegates to a list of other {@link HandlerExceptionResolver}s.
030 *
031 * @author Rossen Stoyanchev
032 * @since 3.1
033 */
034public class HandlerExceptionResolverComposite implements HandlerExceptionResolver, Ordered {
035
036        private List<HandlerExceptionResolver> resolvers;
037
038        private int order = Ordered.LOWEST_PRECEDENCE;
039
040
041        /**
042         * Set the list of exception resolvers to delegate to.
043         */
044        public void setExceptionResolvers(List<HandlerExceptionResolver> exceptionResolvers) {
045                this.resolvers = exceptionResolvers;
046        }
047
048        /**
049         * Return the list of exception resolvers to delegate to.
050         */
051        public List<HandlerExceptionResolver> getExceptionResolvers() {
052                return (this.resolvers != null ? Collections.unmodifiableList(this.resolvers) :
053                                Collections.<HandlerExceptionResolver>emptyList());
054        }
055
056        public void setOrder(int order) {
057                this.order = order;
058        }
059
060        @Override
061        public int getOrder() {
062                return this.order;
063        }
064
065
066        /**
067         * Resolve the exception by iterating over the list of configured exception resolvers.
068         * <p>The first one to return a {@link ModelAndView} wins. Otherwise {@code null} is returned.
069         */
070        @Override
071        public ModelAndView resolveException(
072                        HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) {
073
074                if (this.resolvers != null) {
075                        for (HandlerExceptionResolver handlerExceptionResolver : this.resolvers) {
076                                ModelAndView mav = handlerExceptionResolver.resolveException(request, response, handler, ex);
077                                if (mav != null) {
078                                        return mav;
079                                }
080                        }
081                }
082                return null;
083        }
084
085}