/* * Copyright 2002-2018 the original author or authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.springframework.web.method.annotation; import java.util.Collections; import java.util.List; import org.springframework.lang.Nullable; import org.springframework.util.Assert; import org.springframework.util.ObjectUtils; import org.springframework.web.bind.WebDataBinder; import org.springframework.web.bind.annotation.InitBinder; import org.springframework.web.bind.support.DefaultDataBinderFactory; import org.springframework.web.bind.support.WebBindingInitializer; import org.springframework.web.context.request.NativeWebRequest; import org.springframework.web.method.HandlerMethod; import org.springframework.web.method.support.InvocableHandlerMethod; /** * Adds initialization to a WebDataBinder via {@code @InitBinder} methods. * * @author Rossen Stoyanchev * @since 3.1 */ public class InitBinderDataBinderFactory extends DefaultDataBinderFactory { private final List<InvocableHandlerMethod> binderMethods; /** * Create a new InitBinderDataBinderFactory instance. * @param binderMethods {@code @InitBinder} methods * @param initializer for global data binder initialization */ public InitBinderDataBinderFactory(@Nullable List<InvocableHandlerMethod> binderMethods, @Nullable WebBindingInitializer initializer) { super(initializer); this.binderMethods = (binderMethods != null ? binderMethods : Collections.emptyList()); } /** * Initialize a WebDataBinder with {@code @InitBinder} methods. * <p>If the {@code @InitBinder} annotation specifies attributes names, * it is invoked only if the names include the target object name. * @throws Exception if one of the invoked @{@link InitBinder} methods fails * @see #isBinderMethodApplicable */ @Override public void initBinder(WebDataBinder dataBinder, NativeWebRequest request) throws Exception { for (InvocableHandlerMethod binderMethod : this.binderMethods) { if (isBinderMethodApplicable(binderMethod, dataBinder)) { Object returnValue = binderMethod.invokeForRequest(request, null, dataBinder); if (returnValue != null) { throw new IllegalStateException( "@InitBinder methods must not return a value (should be void): " + binderMethod); } } } } /** * Determine whether the given {@code @InitBinder} method should be used * to initialize the given {@link WebDataBinder} instance. By default we * check the specified attribute names in the annotation value, if any. */ protected boolean isBinderMethodApplicable(HandlerMethod initBinderMethod, WebDataBinder dataBinder) { InitBinder ann = initBinderMethod.getMethodAnnotation(InitBinder.class); Assert.state(ann != null, "No InitBinder annotation"); String[] names = ann.value(); return (ObjectUtils.isEmpty(names) || ObjectUtils.containsElement(names, dataBinder.getObjectName())); } }