android - Asynchronously processing the attached files in an email (Spring Mail Integration) -

if have spring app mail server inbound channel, best way process every file in every email (i poll approx. every 1 min, , fetch 1 email multiple attachments).

although can apply multithreading @ receiving channel (simpleasynctaskexecutor or threadpooltaskexecutor) doesn't because if have 10 files attached in email, processing pretty bound 1 thread.

i've been keeping pretty synchronous until now, because wanted aggregate data every email, , send response after files have been processed. believe done in better way.

in general how can asynchronously process every file in every email, , again asynchronously build email reply?

looks asking java.util.concurrent.future. java core concept block until (method) result calculated. (see javadoc example)

the spring @async support future concept too.

so think need having method uses @async takes 1 attachment of mail argument , returns ever calculated in future. need invoke methods attachments (asynchronous) , store returned future in list. after methods invoked. try feature results in new loop. after loop finish attachments proceed asynchronous.

 processonemail(list<attachement> attachments) {       list<future<attachmentresult>> futures = new arraylist...        for(attachment attachment : attachments) {         futures.add(processoneattachment(attachment)); //async       }        list<attachmentresult> attachmentresults = new arraylist...       for(future<attachmentresult>> future : futures) {          attachmentresults.add(future.get()); //eventually blocks       }       //now attachments calculated , stored in list.             ...     } @async future<attachmentresult> processoneattachment(attachment attachment) {    ... } 

see also: http://blog.espenberntsen.net/2010/03/08/spring-asynchronous-support/