Spring Integration DSL：如何重构为子流？

Question

为了使我的 Spring Integration DSL 代码更具可读性和模块化，我想将像 .scatterGather() 这样的复杂操作提取到子流中。

以此为例说明重构前代码的外观：

@Bean
IntegrationFlow testFlow() {
        return IntegrationFlows
                .from(Http.inboundChannelAdapter("test").get())
                .scatterGather(
                        s -> s
                                .applySequence(true)
                                .recipientFlow(getSubFlow2()),
                        g -> g.outputProcessor(MessageGroup::getOne))
                .log(INFO, m -> m)
                .routeToRecipients(route -> route
                        .recipientFlow(IntegrationFlowDefinition::nullChannel)
                        .get())
                .get();
}

private IntegrationFlow getSubFlow2() {
    return f -> f.handle((m, h) -> 42);
}

这是我想提取到它自己的子流程和方法中的部分：

                .scatterGather(
                        s -> s
                                .applySequence(true)
                                .recipientFlow(getSubFlow2()),
                        g -> g.outputProcessor(MessageGroup::getOne))
                .log(INFO, m -> m)

我想象结果看起来像这样：

@Bean
IntegrationFlow testFlow() {
        return IntegrationFlows
                .from(Http.inboundChannelAdapter("test").get())
                .someMethod(getSubFlow1())
                .routeToRecipients(route -> route
                        .recipientFlow(IntegrationFlowDefinition::nullChannel)
                        .get())
                .get();
}

private IntegrationFlow getSubFlow1() {
        return f -> f
                .scatterGather(
                        s -> s
                                .applySequence(true)
                                .recipientFlow(getSubFlow2()),
                        g -> g.outputProcessor(MessageGroup::getOne))
                .logAndReply(INFO, m -> m)
}

private IntegrationFlow getSubFlow2() {
    return f -> f.handle((m, h) -> 42);
}

这可以通过 Spring Integration DSL 以某种方式完成吗？怎么样？

Answer 1

见gateway(IntegrationFlow)流定义方法：

    /**

 * Populate the "artificial"

 * {@link org.springframework.integration.gateway.GatewayMessageHandler} for the

 * provided {@code subflow}.

 * Typically used with a Java 8 Lambda expression:

 * <pre class="code">

 * {@code

 *  .gateway(f -> f.transform("From Gateway SubFlow: "::concat))

 * }

 * </pre>

 * @param flow the {@link IntegrationFlow} to to send a request message and wait for reply.

 * @return the current {@link BaseIntegrationFlowDefinition}.

 */

public B gateway(IntegrationFlow flow) {