/*
* Copyright 2002-2016 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.bind.annotation;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* Annotation for handling exceptions in specific handler classes and/or
* handler methods.
*
* <p>Handler methods which are annotated with this annotation are allowed to
* have very flexible signatures. They may have parameters of the following
* types, in arbitrary order:
* <ul>
* <li>An exception argument: declared as a general Exception or as a more
* specific exception. This also serves as a mapping hint if the annotation
* itself does not narrow the exception types through its {@link #value()}.
* <li>Request and/or response objects (typically from the Servlet API).
* You may choose any specific request/response type, e.g.
* {@link javax.servlet.ServletRequest} / {@link javax.servlet.http.HttpServletRequest}.
* <li>Session object: typically {@link javax.servlet.http.HttpSession}.
* An argument of this type will enforce the presence of a corresponding session.
* As a consequence, such an argument will never be {@code null}.
* <i>Note that session access may not be thread-safe, in particular in a
* Servlet environment: Consider switching the
* {@link org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter#setSynchronizeOnSession
* "synchronizeOnSession"} flag to "true" if multiple requests are allowed to
* access a session concurrently.</i>
* <li>{@link org.springframework.web.context.request.WebRequest} or
* {@link org.springframework.web.context.request.NativeWebRequest}.
* Allows for generic request parameter access as well as request/session
* attribute access, without ties to the native Servlet API.
* <li>{@link java.util.Locale} for the current request locale
* (determined by the most specific locale resolver available,
* i.e. the configured {@link org.springframework.web.servlet.LocaleResolver}
* in a Servlet environment).
* <li>{@link java.io.InputStream} / {@link java.io.Reader} for access
* to the request's content. This will be the raw InputStream/Reader as
* exposed by the Servlet API.
* <li>{@link java.io.OutputStream} / {@link java.io.Writer} for generating
* the response's content. This will be the raw OutputStream/Writer as
* exposed by the Servlet API.
* <li>{@link org.springframework.ui.Model} as an alternative to returning
* a model map from the handler method. Note that the provided model is not
* pre-populated with regular model attributes and therefore always empty,
* as a convenience for preparing the model for an exception-specific view.
* </ul>
*
* <p>The following return types are supported for handler methods:
* <ul>
* <li>A {@code ModelAndView} object (from Servlet MVC).
* <li>A {@link org.springframework.ui.Model} object, with the view name implicitly
* determined through a {@link org.springframework.web.servlet.RequestToViewNameTranslator}.
* <li>A {@link java.util.Map} object for exposing a model,
* with the view name implicitly determined through a
* {@link org.springframework.web.servlet.RequestToViewNameTranslator}.
* <li>A {@link org.springframework.web.servlet.View} object.
* <li>A {@link String} value which is interpreted as view name.
* <li>{@link ResponseBody @ResponseBody} annotated methods (Servlet-only)
* to set the response content. The return value will be converted to the
* response stream using
* {@linkplain org.springframework.http.converter.HttpMessageConverter message converters}.
* <li>An {@link org.springframework.http.HttpEntity HttpEntity<?>} or
* {@link org.springframework.http.ResponseEntity ResponseEntity<?>} object
* (Servlet-only) to set response headers and content. The ResponseEntity body
* will be converted and written to the response stream using
* {@linkplain org.springframework.http.converter.HttpMessageConverter message converters}.
* <li>{@code void} if the method handles the response itself (by
* writing the response content directly, declaring an argument of type
* {@link javax.servlet.ServletResponse} / {@link javax.servlet.http.HttpServletResponse}
* for that purpose) or if the view name is supposed to be implicitly determined
* through a {@link org.springframework.web.servlet.RequestToViewNameTranslator}
* (not declaring a response argument in the handler method signature).
* </ul>
*
* <p>In Servlet environments, you can combine the {@code ExceptionHandler} annotation
* with {@link ResponseStatus @ResponseStatus}, to define the response status
* for the HTTP response.
*
* @author Arjen Poutsma
* @author Juergen Hoeller
* @since 3.0
* @see org.springframework.web.context.request.WebRequest
*/
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface ExceptionHandler {
/**
* Exceptions handled by the annotated method. If empty, will default to any
* exceptions listed in the method argument list.
*/
Class<? extends Throwable>[] value() default {};
}