io.bitsensor.plugins.shaded.org.springframework.messaging.handler.invocation.AsyncHandlerMethodReturnValueHandler Maven / Gradle / Ivy
/*
* Copyright 2002-2015 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 io.bitsensor.plugins.shaded.org.springframework.messaging.handler.invocation;
import io.bitsensor.plugins.shaded.org.springframework.core.MethodParameter;
import io.bitsensor.plugins.shaded.org.springframework.util.concurrent.ListenableFuture;
/**
* An extension of {@link HandlerMethodReturnValueHandler} for handling async,
* Future-like return value types that support success and error callbacks.
* Essentially anything that can be adapted to a {@link ListenableFuture}.
*
* Implementations should consider extending the convenient base class
* {@link AbstractAsyncReturnValueHandler}.
*
* @author Rossen Stoyanchev
* @since 4.2
* @see AbstractAsyncReturnValueHandler
*/
public interface AsyncHandlerMethodReturnValueHandler extends HandlerMethodReturnValueHandler {
/**
* Whether the return value represents an asynchronous, Future-like type
* with success and error callbacks. If this method returns {@code true},
* then {@link #toListenableFuture} is invoked next. If it returns
* {@code false}, then {@link #handleReturnValue} is called.
*
Note: this method will only be invoked after
* {@link #supportsReturnType(io.bitsensor.plugins.shaded.org.springframework.core.MethodParameter)}
* is called and it returns {@code true}.
* @param returnValue the value returned from the handler method
* @param returnType the type of the return value.
* @return true if the return value type represents an async value.
*/
boolean isAsyncReturnValue(Object returnValue, MethodParameter returnType);
/**
* Adapt the asynchronous return value to a {@link ListenableFuture}.
* Implementations should consider returning an instance of
* {@link io.bitsensor.plugins.shaded.org.springframework.util.concurrent.SettableListenableFuture
* 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
* {@link #supportsReturnType(io.bitsensor.plugins.shaded.org.springframework.core.MethodParameter)}
* is called and it returns {@code true}.
* @param returnValue the value returned from the handler method
* @param returnType the type of the return value.
* @return the resulting ListenableFuture or {@code null} in which case no
* further handling will be performed.
*/
ListenableFuture toListenableFuture(Object returnValue, MethodParameter returnType);
}