org.springframework.web.servlet.mvc.method.annotation.support
Class DefaultMethodReturnValueHandler

java.lang.Object
  org.springframework.web.servlet.mvc.method.annotation.support.DefaultMethodReturnValueHandler

All Implemented Interfaces:

HandlerMethodReturnValueHandler

public class DefaultMethodReturnValueHandler
extends Object
implements HandlerMethodReturnValueHandler

Attempts to handle return value types not recognized by any other HandlerMethodReturnValueHandler. Intended to be used as the last of a list of registered handlers as supportsReturnType(MethodParameter) always returns true.

Handling takes place in the following order:

• Iterate over the list of ModelAndViewResolvers provided to the constructor of this class looking for a return value that isn't ModelAndViewResolver.UNRESOLVED.
• If the return value is not a simple type it is treated as a single model attribute to be added to the model with a name derived from its type.

Note that ModelAndViewResolver is supported for backwards compatibility. Since the only way to check if it supports a return value type is to try to resolve the return value, a ModelAndViewResolver can only be invoked from here after no other HandlerMethodReturnValueHandler has recognized the return value. To avoid this limitation change the ModelAndViewResolver to implement HandlerMethodReturnValueHandler instead.

Since:

3.1

Author:

Rossen Stoyanchev

Constructor Summary

DefaultMethodReturnValueHandler()
Create a DefaultMethodReturnValueHandler instance without ModelAndViewResolvers.

DefaultMethodReturnValueHandler(List<ModelAndViewResolver> mavResolvers)
Create a DefaultMethodReturnValueHandler with a list of ModelAndViewResolvers.

Method Summary

void	handleReturnValue(Object returnValue, MethodParameter returnType, ModelAndViewContainer mavContainer, NativeWebRequest request) Handle the given return value by adding attributes to the model, setting the view (or view name), or by writing to the response.
boolean	supportsReturnType(MethodParameter returnType) Whether the given method return type is supported by this handler.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DefaultMethodReturnValueHandler

public DefaultMethodReturnValueHandler()

Create a DefaultMethodReturnValueHandler instance without ModelAndViewResolvers.

DefaultMethodReturnValueHandler

public DefaultMethodReturnValueHandler(List<ModelAndViewResolver> mavResolvers)

Create a DefaultMethodReturnValueHandler with a list of ModelAndViewResolvers.

Method Detail

supportsReturnType

public boolean supportsReturnType(MethodParameter returnType)

Description copied from interface: HandlerMethodReturnValueHandler

Whether the given method return type is supported by this handler.

Specified by:

supportsReturnType in interface HandlerMethodReturnValueHandler

Parameters:

returnType - the method return type to check

Returns:

true if this handler supports the supplied return type; false otherwise

handleReturnValue

public void handleReturnValue(Object returnValue,
                              MethodParameter returnType,
                              ModelAndViewContainer mavContainer,
                              NativeWebRequest request)
                       throws Exception

Description copied from interface: HandlerMethodReturnValueHandler

Handle the given return value by adding attributes to the model, setting the view (or view name), or by writing to the response. HandlerMethodReturnValueHandler implementations should also consider whether to set ModelAndViewContainer.setResolveView(boolean), which is set to true by default and therefore needs to be set to false explicitly if view resolution is to be bypassed.

Specified by:

handleReturnValue in interface HandlerMethodReturnValueHandler

Parameters:

returnValue - the value returned from the handler method

returnType - the type of the return value. This type must have previously been passed to HandlerMethodReturnValueHandler.supportsReturnType(org.springframework.core.MethodParameter) and it must have returned true

mavContainer - the ModelAndViewContainer for the current request

request - the current request

Throws:

Exception - if the return value handling results in an error