Right way to split, enrich items then send each item to another channel?

Question

Is this the right way to split a list of items, enrich each item and then send each of those enriched items to another channel?

It seems like even though each item is being enriched only the last one is sent to the output channel...

Here is the snipper from my test where I see from the flow for only page2 being invoked.

this.sitePackage = new Package();
this.sitePackage.add(page1);
this.sitePackage.add(page2);
this.sitePackage.add(page3);

//Publish using gateway
this.publishingService.publish(sitePackage);

If I do this however...

this.sitePackage.add(page1);
this.sitePackage.add(page1);

this.sitePackage.add(page2);
this.sitePackage.add(page2);

this.sitePackage.add(page3);
this.sitePackage.add(page3);

I see all the pages being published but the last one is page2 not page3 (even though from debugging I can see the instance has page 3 properties).

It seems like every other item is being seen by the flows...

My flows go like this...

Starting with the PublishPackage flow. This is the main entry flow and intended to split the items out of the package and send each of them, after enriching the payload, to flows who are attached to the publishPackageItem channel...

@Bean
IntegrationFlow flowPublishPackage()
{
    return flow -> flow
        .channel(this.publishPackageChannel())
        .<Package>handle((p, h) -> this.savePackage(p))
        .split(Package.class, this::splitPackage)
        .channel(this.publishPackageItemChannel());
}

@Bean
@PublishPackageChannel
MessageChannel publishPackageChannel()
{
    return MessageChannels.direct().get();
}

@Bean
@PublishPackageItemChannel
MessageChannel publishPackageItemChannel()
{
    return MessageChannels.direct().get();
}

@Splitter
List<PackageEntry> splitPackage(final Package bundle)
{
    final List<PackageEntry> enrichedEntries = new ArrayList<>();
    for (final PackageEntry entry : bundle.getItems())
    {
       enrichedEntries.add(entry);
    }

    return enrichedEntries;
}

@Bean
GatewayProxyFactoryBean publishingGateway()
{
    final GatewayProxyFactoryBean proxy = new GatewayProxyFactoryBean(PublishingService.class);
    proxy.setBeanFactory(this.beanFactory);
    proxy.setDefaultRequestChannel(this.publishPackageChannel());
    proxy.setDefaultReplyChannel(this.publishPackageChannel());
    proxy.afterPropertiesSet();
    return proxy;
}

Next, the CMS publish flows are attached to the publishPackageItem channel and based on the type after splitting, routed to a specific element channel for handling. After splitting the page only specific element types may have a subscribing flow.

@Inject
public CmsPublishFlow(@PublishPackageItemChannel final MessageChannel channelPublishPackageItem)
{
    this.channelPublishPackageItem = channelPublishPackageItem;
}

@Bean
@PublishPageChannel
MessageChannel channelPublishPage()
{
    return MessageChannels.direct().get();
}

@Bean
IntegrationFlow flowPublishContent()
{
    return flow -> flow
        .channel(this.channelPublishPackageItem)
        .filter(PackageEntry.class, p -> p.getEntry() instanceof Page)
        .transform(PackageEntry.class, PackageEntry::getEntry)
        .split(Page.class, this::traversePageElements)
        .<Content, String>route(Content::getType, mapping -> mapping
            .resolutionRequired(false)
            .subFlowMapping(PAGE, sf -> sf.channel(channelPublishPage()))
            .subFlowMapping(IMAGE, sf -> sf.channel(channelPublishAsset()))
            .defaultOutputToParentFlow());
    //.channel(IntegrationContextUtils.NULL_CHANNEL_BEAN_NAME);
}

Finally, my goal is to subscribe to the channel and handle each element accordingly. I subscribe this flow to the channelPublishPage. Each subscriber may handle the element differently.

@Inject
@PublishPageChannel
private MessageChannel channelPublishPage;

@Bean
IntegrationFlow flowPublishPage()
{
    return flow -> flow
        .channel(this.channelPublishPage)
        .publishSubscribeChannel(c -> c
            .subscribe(s -> s
                .<Page>handle((p, h) -> this
                    .generatePage(p))));
}

score 1 · Accepted Answer · answered Aug 18 '17 at 01:54

1

I somehow feel that the problem is here:

proxy.setDefaultRequestChannel(this.publishPackageChannel());
 proxy.setDefaultReplyChannel(this.publishPackageChannel());

Consider do not use the same channel for requests and for waiting replies. This way you bring some loop and really unexpected behavior.

answered Aug 18 '17 at 01:54

Artem Bilan

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That definitely helped with some of the wonkiness of testing the gateway. The real culprit I eventually found out was that in my unit test, which I failed to realize until I turned on logging, was that I was bridging a QueuedChannel to the publishItemsChannel. Once I reworked that everything worked fine. Thanks for the tip on the gateway though. – KJQ Aug 18 '17 at 08:51

Right way to split, enrich items then send each item to another channel?

1 Answers1