Spring Integration DSL - Outbound Gateway with access to Headers

Question

I'm having an issue with Spring Integration. I'm using Spring Boot 1.4.0.RELEASE, Spring Integration 4.3.1.RELEASE, Spring Integration DSL 1.2.0.M1.

What I'm trying to do:

I'm writing an application that will read files from FTP and local file system (using inbound channel adapters), transfer the files to a local working directory (using file outbound gateways), process, then move them to a final destination (file outbound gateway/adapters).

EDIT: The original issue stemmed from incorrect usage of the OutboundGateway. For details of what I was doing wrong, look at the edit history.

I'm having a problem with wiring an OutboundGateway that needs information from the message header.

My basic flow is:

@Bean
@SuppressWarnings("unchecked")
public IntegrationFlow fileSystemReadingFlow() {
    LOGGER.debug("Building fileSystemReadingFlow.");
    // Create a FileInboundChannelAdapter

        return IntegrationFlows.from(s -> s.file(new File(StringUtils.cleanPath(Paths.get(directoryProperties.getLocal() , UNKNOWN).toString())))
                        // Add a Filter to restrict which files are retrieved
                        .filter(fileListFilterBuilder.buildFileListFilter(File.class))
                // Add a poller to continually watch the directory
                , endpointConfigurer -> endpointConfigurer.poller(poller)
        )
                .enrichHeaders(h -> h.header(FOLDER_NAME, LOCAL))
                .handle((message, headers) -> Files.outboundGateway(new File( StringUtils.cleanPath(Paths.get(directoryProperties.getWorking()
                                    , (String) headers.get(FOLDER_NAME)).toString()))).deleteSourceFiles(true).autoCreateDirectory(true) )
                // Send the files to the aggregatingChannel
                .channel("aggregatingFileChannel")
                .get();
  }

The issue is the handle((message, headers) -> Files.outboundGateway(...) section. Using the lambda method above spits out this error over and over.

ErrorMessage [payload=org.springframework.messaging.MessagingException: failed to resolve channel name 'org.springframework.integration.dsl.file.FileWritingMessageHandlerSpec'; nested exception is org.springframework.messaging.core.DestinationResolutionException: failed to look up MessageChannel with name 'org.springframework.integration.dsl.file.FileWritingMessageHandlerSpec' in the BeanFactory.; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'org.springframework.integration.dsl.file.FileWritingMessageHandlerSpec' is defined, headers={id=e3f5f341-6379-0dd0-11e6-e4bff8f455b0, timestamp=1471619276894}]

The documentation and my testing show that defining it like below works. But, how do I get access to the headers?

.handle(Files.outboundGateway(new File( "someDir"))).deleteSourceFiles(true).autoCreateDirectory(true) )

I've tried using a SpEl expression, which may be the right method, but I didn't get it to work.

.handle(Files.outboundGateway("StringUtils.cleanPath(Paths.get(directoryProperties.getWorking()" +
                                    ", headers[FOLDER_NAME]).toString())").deleteSourceFiles(true).autoCreateDirectory(true) )

Answer 1

After re-reading the SpEL reference, I was able to figure out my problem. I needed to explicitly reference the static methods I needed to call and then escape the literals properly.

.handle(Files.outboundGateway("T(org.springframework.util.StringUtils).cleanPath(T(java.nio.file.Paths).get('" +directoryProperties.getWorking() +"'" +
                                    ", headers['"+FOLDER_NAME+"']).toString())").deleteSourceFiles(true).autoCreateDirectory(true) )