/* * Copyright 2012-2019 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.cloud.function.context.message; import java.lang.reflect.Method; import java.util.Collections; import java.util.HashMap; import java.util.Map; import org.springframework.cloud.function.core.FluxWrapper; import org.springframework.cloud.function.core.Isolated; import org.springframework.messaging.Message; import org.springframework.messaging.support.MessageBuilder; import org.springframework.util.ClassUtils; import org.springframework.util.ReflectionUtils; /** * @author Dave Syer * */ public abstract class MessageUtils { /** * Create a message for the handler. If the handler is a wrapper for a function in an * isolated class loader, then the message will be created with the target class * loader (therefore the {@link Message} class must be on the classpath of the target * class loader). * @param handler the function that will be applied to the message * @param payload the payload of the message * @param headers the headers for the message * @return a message with the correct class loader */ public static Object create(Object handler, Object payload, Map<String, Object> headers) { if (handler instanceof FluxWrapper) { handler = ((FluxWrapper<?>) handler).getTarget(); } if (payload instanceof Message) { headers = new HashMap<>(headers); headers.putAll(((Message<?>) payload).getHeaders()); payload = ((Message<?>) payload).getPayload(); } if (!(handler instanceof Isolated)) { return MessageBuilder.withPayload(payload).copyHeaders(headers).build(); } ClassLoader classLoader = ((Isolated) handler).getClassLoader(); Class<?> builder = ClassUtils.resolveClassName(MessageBuilder.class.getName(), classLoader); Method withPayload = ClassUtils.getMethod(builder, "withPayload", Object.class); Method copyHeaders = ClassUtils.getMethod(builder, "copyHeaders", Map.class); Method build = ClassUtils.getMethod(builder, "build"); Object instance = ReflectionUtils.invokeMethod(withPayload, null, payload); ReflectionUtils.invokeMethod(copyHeaders, instance, headers); return ReflectionUtils.invokeMethod(build, instance); } /** * Convert a message from the handler into one that is safe to consume in the caller's * class loader. If the handler is a wrapper for a function in an isolated class * loader, then the message will be created with the target class loader (therefore * the {@link Message} class must be on the classpath of the target class loader). * @param handler the function that generated the message * @param message the message to convert * @return a message with the correct class loader */ public static Message<?> unpack(Object handler, Object message) { if (handler instanceof FluxWrapper) { handler = ((FluxWrapper<?>) handler).getTarget(); } if (!(handler instanceof Isolated)) { if (message instanceof Message) { return (Message<?>) message; } return MessageBuilder.withPayload(message).build(); } ClassLoader classLoader = ((Isolated) handler).getClassLoader(); Class<?> type = ClassUtils.isPresent(Message.class.getName(), classLoader) ? ClassUtils.resolveClassName(Message.class.getName(), classLoader) : null; Object payload; Map<String, Object> headers; if (type != null && type.isAssignableFrom(message.getClass())) { Method getPayload = ClassUtils.getMethod(type, "getPayload"); Method getHeaders = ClassUtils.getMethod(type, "getHeaders"); payload = ReflectionUtils.invokeMethod(getPayload, message); @SuppressWarnings("unchecked") Map<String, Object> map = (Map<String, Object>) ReflectionUtils .invokeMethod(getHeaders, message); headers = map; } else { payload = message; headers = Collections.emptyMap(); } return MessageBuilder.withPayload(payload).copyHeaders(headers).build(); } }