Integration of legacy systems made easy

1. Integration with Camel
Integration of legacy applications made easy

2. Integration

3. Integration

4. Integration

5. Case
Flat files

6. Apache Camel
X

7. Problems

8. from("file://${file.directory}?delay=${delay}&move=${destination}/" + filename).
setHeader('ReturnFileLayout', "${file.layout}").
process(digestProcessor).
process(idempotencyProcessor).
choice().
when(header('ReturnFileDuplicate')).
setHeader('ReturnFileStatus', simple('duplicate')).
process(logProcessor).
otherwise().
process(splitProcessor).
process(sequenceProcessor).
policy(dataSources.transactedPolicy).
process(lineProcessor).
end().
policy(dataSources.notTransactedPolicy).
setHeader('ReturnFileStatus', simple('done')).
process(logProcessor).
end().
endChoice().
end()

9. class SplitProcessor implements Processor {
void process(Exchange exchange) throws Exception {
def file = exchange.in.body as GenericFile<File>
exchange.out.body = [lines: file.file.readLines(), original: file]
exchange.out.headers = exchange.in.headers
}
}
class LineProcessor implements Processor {
ReturnFileDao dao
void process(Exchange exchange) throws Exception {
def headers = exchange.in.headers
def body = exchange.in.body as Map
dao.insert(headers.ReturnFileId, headers.ReturnFileBank, headers.ReturnFileLayout, body.lines)
exchange.out.headers = headers
exchange.out.body = body.original
}
}

10. onException(RuntimeException).
continued(false).
maximumRedeliveries(0).
log(LoggingLevel.ERROR, 'Exception on Camel route: ${headers.CamelExceptionCaught}').
to('direct:saveError')
from('direct:saveError').
setHeader('ReturnFileStatus', simple('error')).
process(logProcessor)

11. Good parts
- Integration of applications with different protocols & technologies
- Every integration use same concepts
- Abstraction of implementation details
- Easy to define retry & transaction policies

12. Pain points
- Very large integration projects (go with microservices & APIs)
- Writing unit tests is not intuitive

13. Further reading
Enterprise Integration Patterns book:
http://www.enterpriseintegrationpatterns.com/
Apache Camel Developer’s Cookbook:
https://www.packtpub.com/application-development/apache-cam
el-developers-cookbook
Apache Camel Components:
http://camel.apache.org/components.html