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.method.annotation;
018
019import java.util.Collections;
020import java.util.List;
021
022import org.springframework.util.ObjectUtils;
023import org.springframework.web.bind.WebDataBinder;
024import org.springframework.web.bind.annotation.InitBinder;
025import org.springframework.web.bind.support.DefaultDataBinderFactory;
026import org.springframework.web.bind.support.WebBindingInitializer;
027import org.springframework.web.context.request.NativeWebRequest;
028import org.springframework.web.method.HandlerMethod;
029import org.springframework.web.method.support.InvocableHandlerMethod;
030
031/**
032 * Adds initialization to a WebDataBinder via {@code @InitBinder} methods.
033 *
034 * @author Rossen Stoyanchev
035 * @since 3.1
036 */
037public class InitBinderDataBinderFactory extends DefaultDataBinderFactory {
038
039        private final List<InvocableHandlerMethod> binderMethods;
040
041
042        /**
043         * Create a new InitBinderDataBinderFactory instance.
044         * @param binderMethods {@code @InitBinder} methods
045         * @param initializer for global data binder initialization
046         */
047        public InitBinderDataBinderFactory(List<InvocableHandlerMethod> binderMethods, WebBindingInitializer initializer) {
048                super(initializer);
049                this.binderMethods = (binderMethods != null ? binderMethods : Collections.<InvocableHandlerMethod>emptyList());
050        }
051
052
053        /**
054         * Initialize a WebDataBinder with {@code @InitBinder} methods.
055         * <p>If the {@code @InitBinder} annotation specifies attributes names,
056         * it is invoked only if the names include the target object name.
057         * @throws Exception if one of the invoked @{@link InitBinder} methods fails
058         * @see #isBinderMethodApplicable
059         */
060        @Override
061        public void initBinder(WebDataBinder dataBinder, NativeWebRequest request) throws Exception {
062                for (InvocableHandlerMethod binderMethod : this.binderMethods) {
063                        if (isBinderMethodApplicable(binderMethod, dataBinder)) {
064                                Object returnValue = binderMethod.invokeForRequest(request, null, dataBinder);
065                                if (returnValue != null) {
066                                        throw new IllegalStateException(
067                                                        "@InitBinder methods must not return a value (should be void): " + binderMethod);
068                                }
069                        }
070                }
071        }
072
073        /**
074         * Determine whether the given {@code @InitBinder} method should be used
075         * to initialize the given {@link WebDataBinder} instance. By default we
076         * check the specified attribute names in the annotation value, if any.
077         */
078        protected boolean isBinderMethodApplicable(HandlerMethod initBinderMethod, WebDataBinder dataBinder) {
079                InitBinder ann = initBinderMethod.getMethodAnnotation(InitBinder.class);
080                String[] names = ann.value();
081                return (ObjectUtils.isEmpty(names) || ObjectUtils.containsElement(names, dataBinder.getObjectName()));
082        }
083
084}