/*
* 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()));
}
}
