Spring Metadatastore Integration

I added a bean called metadataStore to my spring boot + spring integration application and expected the ftp sync to be preserved and not corrupted even after restarting the server. However, my early tests show otherwise; If I start the server and let it collect and process 3 test files and then restart the server, then those same 3 files will be processed and processed again - as if no persistent metadata store was defined at all.

I wonder if some of the configuration details are missing when setting up the datastore ...

@Configuration
public class MetadataStoreConfiguration {

    @Bean
    public PropertiesPersistingMetadataStore metadataStore() {
        PropertiesPersistingMetadataStore metadataStore = new PropertiesPersistingMetadataStore();
        return metadataStore;
    }
}

      

        
        
        
      

    

Also, I see in the spring integration reference for a short example on how to set up an idempotent sink and metadata store. Is this what my implementation is missing?

If so, and if I need to set it like in the example, where will I define my calls to metadataStore.get and metadataStore.put? the outbound adapter I'm using doesn't provide me with an expression attribute ... Here is my naive and incomplete attempt:

<int-file:inbound-channel-adapter id="inboundLogFile"
                                  auto-create-directory="true"
                                  directory="${sftp.local.dir}"
                                  channel="fileInboundChannel"
                                  prevent-duplicates="true">
    <int:poller fixed-rate="${setup.inbound.poller.rate}"/>
</int-file:inbound-channel-adapter>


<int:filter id="fileFilter" input-channel="fileInboundChannel"
                output-channel="idempotentServiceChannel"
                discard-channel="fileDiscardChannel"
                expression="@metadataStore.get(payload.name) == null"/>

      

        
        
        
      

    

This is the outbound adapter used in the example:

<int:outbound-channel-adapter channel="idempotentServiceChannel" expression="@metadataStore.put(payload.name, '')"/>

      

        
        
        
      

    

In my outgoing ftp adapter, I cannot insert the above expression :(

<int-ftp:outbound-channel-adapter id="sdkOutboundFtp"
                                      channel="idempotentServiceChannel"
                                      session-factory="ftpsCachingSessionFactory"
                                      charset="UTF-8"
                                      auto-create-directory="true"
                                      use-temporary-file-name="false"
                                      remote-file-separator="/"
                                      remote-directory-expression="${egnyte.remote.dir}"
                                      * NO EXPRESSION POSSIBLE HERE *
                                      mode="REPLACE">
    </int-ftp:outbound-channel-adapter>