org.springframework.messaging.handler.invocation.HandlerMethodReturnValueHandlerComposite Maven / Gradle / Ivy
/*
* Copyright 2002-2019 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
*
* https://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.messaging.handler.invocation;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.core.MethodParameter;
import org.springframework.lang.Nullable;
import org.springframework.messaging.Message;
import org.springframework.util.concurrent.ListenableFuture;
/**
* A HandlerMethodReturnValueHandler that wraps and delegates to others.
*
* @author Rossen Stoyanchev
* @since 4.0
*/
public class HandlerMethodReturnValueHandlerComposite implements AsyncHandlerMethodReturnValueHandler {
/** Public for wrapping with fallback logger. */
public static final Log defaultLogger = LogFactory.getLog(HandlerMethodReturnValueHandlerComposite.class);
private Log logger = defaultLogger;
private final List returnValueHandlers = new ArrayList<>();
/**
* Set an alternative logger to use than the one based on the class name.
* @param logger the logger to use
* @since 5.1
*/
public void setLogger(Log logger) {
this.logger = logger;
}
/**
* Return the currently configured Logger.
* @since 5.1
*/
public Log getLogger() {
return logger;
}
/**
* Return a read-only list with the configured handlers.
*/
public List getReturnValueHandlers() {
return Collections.unmodifiableList(this.returnValueHandlers);
}
/**
* Clear the list of configured handlers.
*/
public void clear() {
this.returnValueHandlers.clear();
}
/**
* Add the given {@link HandlerMethodReturnValueHandler}.
*/
public HandlerMethodReturnValueHandlerComposite addHandler(HandlerMethodReturnValueHandler returnValueHandler) {
this.returnValueHandlers.add(returnValueHandler);
return this;
}
/**
* Add the given {@link HandlerMethodReturnValueHandler HandlerMethodReturnValueHandlers}.
*/
public HandlerMethodReturnValueHandlerComposite addHandlers(
@Nullable List handlers) {
if (handlers != null) {
this.returnValueHandlers.addAll(handlers);
}
return this;
}
@Override
public boolean supportsReturnType(MethodParameter returnType) {
return getReturnValueHandler(returnType) != null;
}
@SuppressWarnings("ForLoopReplaceableByForEach")
@Nullable
private HandlerMethodReturnValueHandler getReturnValueHandler(MethodParameter returnType) {
for (int i = 0; i < this.returnValueHandlers.size(); i++) {
HandlerMethodReturnValueHandler handler = this.returnValueHandlers.get(i);
if (handler.supportsReturnType(returnType)) {
return handler;
}
}
return null;
}
@Override
public void handleReturnValue(@Nullable Object returnValue, MethodParameter returnType, Message message)
throws Exception {
HandlerMethodReturnValueHandler handler = getReturnValueHandler(returnType);
if (handler == null) {
throw new IllegalStateException("No handler for return value type: " + returnType.getParameterType());
}
if (logger.isTraceEnabled()) {
logger.trace("Processing return value with " + handler);
}
handler.handleReturnValue(returnValue, returnType, message);
}
@Override
public boolean isAsyncReturnValue(Object returnValue, MethodParameter returnType) {
HandlerMethodReturnValueHandler handler = getReturnValueHandler(returnType);
return (handler instanceof AsyncHandlerMethodReturnValueHandler &&
((AsyncHandlerMethodReturnValueHandler) handler).isAsyncReturnValue(returnValue, returnType));
}
@Override
@Nullable
public ListenableFuture toListenableFuture(Object returnValue, MethodParameter returnType) {
HandlerMethodReturnValueHandler handler = getReturnValueHandler(returnType);
if (handler instanceof AsyncHandlerMethodReturnValueHandler) {
return ((AsyncHandlerMethodReturnValueHandler) handler).toListenableFuture(returnValue, returnType);
}
return null;
}
}