Class HandlerMethodReturnValueHandlerComposite

java.lang.Object

org.springframework.messaging.handler.invocation.HandlerMethodReturnValueHandlerComposite

All Implemented Interfaces:

AsyncHandlerMethodReturnValueHandler, HandlerMethodReturnValueHandler

public class HandlerMethodReturnValueHandlerComposite
extends Object
implements AsyncHandlerMethodReturnValueHandler

A HandlerMethodReturnValueHandler that wraps and delegates to others.

Since:

4.0

Author:

Rossen Stoyanchev

Field Summary

Fields

Modifier and Type	Field	Description
static final org.apache.commons.logging.Log	defaultLogger	Public for wrapping with fallback logger.

Constructor Summary

Constructors

Constructor	Description
HandlerMethodReturnValueHandlerComposite()

Method Summary

Modifier and Type	Method	Description
HandlerMethodReturnValueHandlerComposite	addHandler(HandlerMethodReturnValueHandler returnValueHandler)	Add the given HandlerMethodReturnValueHandler.
HandlerMethodReturnValueHandlerComposite	addHandlers(@Nullable List<? extends HandlerMethodReturnValueHandler> handlers)	Add the given HandlerMethodReturnValueHandlers.
void	clear()	Clear the list of configured handlers.
org.apache.commons.logging.Log	getLogger()	Return the currently configured Logger.
List<HandlerMethodReturnValueHandler>	getReturnValueHandlers()	Return a read-only list with the configured handlers.
void	handleReturnValue(@Nullable Object returnValue, org.springframework.core.MethodParameter returnType, Message<?> message)	Handle the given return value.
boolean	isAsyncReturnValue(Object returnValue, org.springframework.core.MethodParameter returnType)	Whether the return value represents an asynchronous, Future-like type with success and error callbacks.
void	setLogger(org.apache.commons.logging.Log logger)	Set an alternative logger to use than the one based on the class name.
boolean	supportsReturnType(org.springframework.core.MethodParameter returnType)	Whether the given method return type is supported by this handler.
@Nullable CompletableFuture<?>	toCompletableFuture(Object returnValue, org.springframework.core.MethodParameter returnType)	Adapt the asynchronous return value to a CompletableFuture.

Methods inherited from class java.lang.Object

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

Field Details

defaultLogger

public static final org.apache.commons.logging.Log defaultLogger

Public for wrapping with fallback logger.

Constructor Details

HandlerMethodReturnValueHandlerComposite

public HandlerMethodReturnValueHandlerComposite()

Method Details

setLogger

public void setLogger(org.apache.commons.logging.Log logger)

Set an alternative logger to use than the one based on the class name.

Parameters:

logger - the logger to use

Since:

5.1

getLogger

public org.apache.commons.logging.Log getLogger()

Return the currently configured Logger.

Since:

5.1

getReturnValueHandlers

public List<HandlerMethodReturnValueHandler> getReturnValueHandlers()

Return a read-only list with the configured handlers.

clear

public void clear()

Clear the list of configured handlers.

addHandler

public HandlerMethodReturnValueHandlerComposite addHandler(HandlerMethodReturnValueHandler returnValueHandler)

Add the given HandlerMethodReturnValueHandler.

addHandlers

public HandlerMethodReturnValueHandlerComposite addHandlers(@Nullable List<? extends HandlerMethodReturnValueHandler> handlers)

Add the given HandlerMethodReturnValueHandlers.

supportsReturnType

public boolean supportsReturnType(org.springframework.core.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(@Nullable Object returnValue,
 org.springframework.core.MethodParameter returnType,
 Message<?> message)
                       throws Exception

Description copied from interface: HandlerMethodReturnValueHandler

Handle the given return value.

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.

message - the message that caused this method to be called

Throws:

Exception - if the return value handling results in an error

isAsyncReturnValue

public boolean isAsyncReturnValue(Object returnValue,
 org.springframework.core.MethodParameter returnType)

Description copied from interface: AsyncHandlerMethodReturnValueHandler

Whether the return value represents an asynchronous, Future-like type with success and error callbacks. If this method returns true, then AsyncHandlerMethodReturnValueHandler.toCompletableFuture(java.lang.Object, org.springframework.core.MethodParameter) is invoked next. If it returns false, then HandlerMethodReturnValueHandler.handleReturnValue(java.lang.Object, org.springframework.core.MethodParameter, org.springframework.messaging.Message<?>) is called.

Note: this method will only be invoked after HandlerMethodReturnValueHandler.supportsReturnType(org.springframework.core.MethodParameter) is called and it returns true.

Specified by:

isAsyncReturnValue in interface AsyncHandlerMethodReturnValueHandler

Parameters:

returnValue - the value returned from the handler method

returnType - the type of the return value

Returns:

true if the return value type represents an async value

toCompletableFuture

public @Nullable CompletableFuture<?> toCompletableFuture(Object returnValue,
 org.springframework.core.MethodParameter returnType)

Description copied from interface: AsyncHandlerMethodReturnValueHandler

Adapt the asynchronous return value to a CompletableFuture.

Return value handling will then continue when the CompletableFuture is completed with either success or error.

Note: this method will only be invoked after HandlerMethodReturnValueHandler.supportsReturnType(org.springframework.core.MethodParameter) is called and it returns true.

Specified by:

toCompletableFuture in interface AsyncHandlerMethodReturnValueHandler

Parameters:

returnValue - the value returned from the handler method

returnType - the type of the return value

Returns:

the resulting CompletableFuture, or null in which case no further handling will be performed