org.springframework.messaging.handler.annotation.support.AnnotationExceptionHandlerMethodResolver Maven / Gradle / Ivy
/*
* 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.messaging.handler.annotation.support;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.springframework.core.MethodIntrospector;
import org.springframework.core.annotation.AnnotatedElementUtils;
import org.springframework.messaging.handler.annotation.MessageExceptionHandler;
import org.springframework.messaging.handler.invocation.AbstractExceptionHandlerMethodResolver;
/**
* A sub-class of {@link AbstractExceptionHandlerMethodResolver} that looks for
* {@link MessageExceptionHandler}-annotated methods in a given class. The actual
* exception types handled are extracted either from the annotation, if present,
* or from the method signature as a fallback option.
*
* @author Rossen Stoyanchev
* @author Juergen Hoeller
* @since 4.0
*/
public class AnnotationExceptionHandlerMethodResolver extends AbstractExceptionHandlerMethodResolver {
/**
* A constructor that finds {@link MessageExceptionHandler} methods in the given type.
* @param handlerType the type to introspect
*/
public AnnotationExceptionHandlerMethodResolver(Class handlerType) {
super(initExceptionMappings(handlerType));
}
private static Map, Method> initExceptionMappings(Class handlerType) {
Map methods = MethodIntrospector.selectMethods(handlerType,
(MethodIntrospector.MetadataLookup) method ->
AnnotatedElementUtils.findMergedAnnotation(method, MessageExceptionHandler.class));
Map, Method> result = new HashMap<>();
for (Map.Entry entry : methods.entrySet()) {
Method method = entry.getKey();
List> exceptionTypes = new ArrayList<>();
exceptionTypes.addAll(Arrays.asList(entry.getValue().value()));
if (exceptionTypes.isEmpty()) {
exceptionTypes.addAll(getExceptionsFromMethodSignature(method));
}
for (Class exceptionType : exceptionTypes) {
Method oldMethod = result.put(exceptionType, method);
if (oldMethod != null && !oldMethod.equals(method)) {
throw new IllegalStateException("Ambiguous @ExceptionHandler method mapped for [" +
exceptionType + "]: {" + oldMethod + ", " + method + "}");
}
}
}
return result;
}
}