CODEWITHSUNDEEP
javaapache-cameldslthrottling
vikingsteve
vikingsteve

Reputation: 40428

Apache camel: filter / throttle to take just the first message from a queue

What's the simplest way to take just the first message from a queue?

Given that there is nothing I can see in the header to filter on (no sequence numbers, or the like, at least as far as I can see), is there anything better than this?

from("webspheremq:topic:SNAPSHOTS")
    .throttle(1).timePeriodMillis(1234567890L * 1000)
    .to("direct:anotherqueue")

Prefer camel DSL over beans + java code :)

Edit

actually reading from a webspheremq topic.

Edit2

don't use Long.MAX_VALUE as the time period! Try 1234567890L * 1000 instead

Upvotes: 1

Views: 371

Answers (1)

Anders R. Bystrup
Anders R. Bystrup

Reputation: 16080

You could try to filter using a singleton holding first-ness state:

public static class FirstOrNot {
    private static FirstOrNot _instance;

    public synchronized boolean isfirst() {
        if ( _instance == null ) {
            _instance = new FirstOrNot();
            return true;
        }
        return false;
    }
}

FirstOrNot first = new FirstOrNot();

from("webspheremq:topic:SNAPSHOTS")
    .filter().method( first , "isFirst" )
    .to("direct:anotherqueue")

Perhaps you can use this as a starting point.

Cheers,

Upvotes: 1

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