Breaking up DSL IntegrationFlows - spring-integration

Question

I've been playing around with Spring Integration (SI) DSL. I have a Rest service with the following Async Gateway defined :
#MessagingGateway
public interface Provision {
#Async
#Gateway(requestChannel = "provision.input")
ListenableFuture<List<ResultDto>> provision(List<ItemsDto> stuff);
}
From the Line-by-line walk-through I have the follow example IntegrationFlow.
#Bean
public IntegrationFlow provision() {
return f -> f
.split(ArrayList.class, List::toArray)
.channel(c -> c.executor(Executors.newCachedThreadPool()))
.<ItemsDto, String>route(ItemsDto::getType, m -> m
.subFlowMapping("IPTV", sf -> sf
.<ItemsDto, String>route(ItemsDto::getAction, m2 -> m2
.subFlowMapping("OPEN", sf2 -> sf2
.handle((p, h) -> iptvService.open((ItemsDto) p))))
)
)
.aggregate();
}
I have several layers of routing as you can see. I need to break things up a bit. I've tried several things which don't work (here I don't get a response...the thread doesn't wait):
#Bean(name = "routerInput")
private MessageChannel routerInput() {
return MessageChannels.direct().get();
}
#Bean
public IntegrationFlow provision() {
return f -> f
.split(ArrayList.class, List::toArray)
.channel(c -> c.executor(Executors.newCachedThreadPool()))
.<ItemsDto, String>route(ItemsDto::getType, m ->
m.subFlowMapping("IPTV", sf -> sf.channel("routerInput"))
)
.aggregate();
}
#Bean
public IntegrationFlow action() {
return IntegrationFlows.from("routerInput")
.<ItemsDto, String>route(ItemsDto::getAction, m -> m
.subFlowMapping("OPEN", sf -> sf
.handle(p -> iptvService.open((ItemsDto) p.getPayload())))).get();
}
I'm obviously conceptually missing something :) Can someone perhaps assist with a "how to and why" opinion?
I have a list of items that need to be split, routed by "type", then routed by "action", and finally aggregated (containing response of handler). Each handled item needs to process in parallel.
Thanks in advance
Update:
From Artem's suggestion I removed all the async stuff. I trimmed it down to almost nothing...
#Bean(name = "routerInput")
private MessageChannel routerInput() {
return MessageChannels.direct().get();
}
#Bean
public IntegrationFlow provision() {
return f -> f
.split()
.<ItemDto, String>route(ItemDto::getType, m ->
m.subFlowMapping("IPTV", sf -> sf.channel("routerInput")))
.aggregate();
}
#Bean
public IntegrationFlow action() {
return IntegrationFlows.from("routerInput")
.<ItemDto, String>route(ItemDto::getAction, m -> m
.subFlowMapping("OPEN", sf -> sf
.handle((p, h) -> iptvService.open((ItemDto) p)))).get();
}
I got it to respond by changing
.handle(p ->
to this
.handle((p, h) ->
So it at least responds, but it does not aggregate the 3 test items that were split. Output consists of 1 item. Do I need to use a stream collect? Release policy? Shouldn't this be fine?

Answer 1

It's probably simpler to use channelMapping rather than subflowMapping if you want to break it apart...
#Bean
public IntegrationFlow typeRoute() {
return IntegrationFlows.from(foo())
.split()
.<ItemsDto, String>route(ItemsDto::getType, m -> m
.channelMapping("foo", "channel1")
.channelMapping("bar", "channel2"))
.get();
}
#Bean
public IntegrationFlow fooActionRoute() {
return IntegrationFlows.from(channel1())
.<ItemsDto, String>route(ItemsDto::getAction, m -> m
.channelMapping("foo", "channel3")
.channelMapping("bar", "channel4"))
.get();
}
#Bean
public IntegrationFlow barActionRoute() {
return IntegrationFlows.from(channel1())
.<ItemsDto, String>route(ItemsDto::getAction, m -> m
.channelMapping("foo", "channel5")
.channelMapping("bar", "channel6"))
.get();
}
#Bean
public IntegrationFlow fooFooHandle() {
return IntegrationFlows.from(channel3())
// handle
.channel(aggChannel())
.get();
}
Create flows for the other options and aggregate each result:
// fooBarHandle(), barFooHandle(), barBarHandle()
#Bean IntegrationFlow agg() {
return IntegrationFlows.from(aggChannel())
.aggregate()
.get();
}
The parallelism is handled by using ExecutorChannels...
#Bean
public MessageChannel channel1() {
return new ExecutorChannel(exec());
}
#Bean
public MessageChannel channel2() {
return new ExecutorChannel(exec());
}
#Bean
public MessageChannel channel3() {
return new DirectChannel();
}
#Bean
public MessageChannel channel4() {
return new DirectChannel();
}
#Bean
public MessageChannel channel5() {
return new DirectChannel();
}
#Bean
public MessageChannel channel6() {
return new DirectChannel();
}
#Bean
public MessageChannel aggChannel() {
return new DirectChannel();
}

Answer 2

I don't see any big problems in your configuration and it really should work.
Want I don't like there is:
If you use async Gateway (ListenableFuture<List<ResultDto>>) you don't need #Async annotation there, because it will be already by the Gateway contract.
You don't need convert List::toArray if your payload is a List already. It is just enough to use .split() without params.
That's for the design style.
I'm not sure yet what's the problem there, but would you mind to make your whole flow sync and share with us here the DEBUG for the flow and point out where you see the problem.

Answer 3

Moved the aggregate to the "action" Bean and it worked.
Thanks for your patience :)