org.springframework.messaging.handler.invocation

Class HandlerMethodReturnValueHandlerComposite

java.lang.Object

org.springframework.messaging.handler.invocation.HandlerMethodReturnValueHandlerComposite

All Implemented Interfaces:

AsyncHandlerMethodReturnValueHandler, HandlerMethodReturnValueHandler

public class HandlerMethodReturnValueHandlerComposite
extends java.lang.Object
implements AsyncHandlerMethodReturnValueHandler

A HandlerMethodReturnValueHandler that wraps and delegates to others.

Since:

4.0

Author:

Rossen Stoyanchev

Field Summary

Fields

Modifier and Type	Field and Description
private static Log	logger
private java.util.List<HandlerMethodReturnValueHandler>	returnValueHandlers

Constructor Summary

Constructors

Constructor and Description
HandlerMethodReturnValueHandlerComposite()

Method Summary

Modifier and Type	Method and Description
HandlerMethodReturnValueHandlerComposite	addHandler(HandlerMethodReturnValueHandler returnValuehandler) Add the given HandlerMethodReturnValueHandler.
HandlerMethodReturnValueHandlerComposite	addHandlers(java.util.List<? extends HandlerMethodReturnValueHandler> handlers) Add the given HandlerMethodReturnValueHandlers.
void	clear() Clear the list of configured handlers.
private HandlerMethodReturnValueHandler	getReturnValueHandler(MethodParameter returnType)
java.util.List<HandlerMethodReturnValueHandler>	getReturnValueHandlers() Return a read-only list with the configured handlers.
void	handleReturnValue(java.lang.Object returnValue, MethodParameter returnType, Message<?> message) Handle the given return value.
boolean	isAsyncReturnValue(java.lang.Object returnValue, MethodParameter returnType) Whether the return value represents an asynchronous, Future-like type with success and error callbacks.
boolean	supportsReturnType(MethodParameter returnType) Whether the given method return type is supported by this handler.
ListenableFuture<?>	toListenableFuture(java.lang.Object returnValue, MethodParameter returnType) Adapt the asynchronous return value to a ListenableFuture.

Methods inherited from class java.lang.Object

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

Field Detail

logger

private static final Log logger

returnValueHandlers

private final java.util.List<HandlerMethodReturnValueHandler> returnValueHandlers

Constructor Detail

HandlerMethodReturnValueHandlerComposite

public HandlerMethodReturnValueHandlerComposite()

Method Detail

getReturnValueHandlers

public java.util.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(java.util.List<? extends HandlerMethodReturnValueHandler> handlers)

Add the given HandlerMethodReturnValueHandlers.

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

getReturnValueHandler

private HandlerMethodReturnValueHandler getReturnValueHandler(MethodParameter returnType)

handleReturnValue

public void handleReturnValue(java.lang.Object returnValue,
                              MethodParameter returnType,
                              Message<?> message)
                       throws java.lang.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:

java.lang.Exception - if the return value handling results in an error

isAsyncReturnValue

public boolean isAsyncReturnValue(java.lang.Object returnValue,
                                  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.toListenableFuture(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.

toListenableFuture

public ListenableFuture<?> toListenableFuture(java.lang.Object returnValue,
                                              MethodParameter returnType)

Description copied from interface: AsyncHandlerMethodReturnValueHandler

Adapt the asynchronous return value to a ListenableFuture. Implementations should consider returning an instance of SettableListenableFuture. Return value handling will then continue when the ListenableFuture 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:

toListenableFuture in interface AsyncHandlerMethodReturnValueHandler

Parameters:

returnValue - the value returned from the handler method

returnType - the type of the return value.

Returns:

the resulting ListenableFuture or null in which case no further handling will be performed.