workaround for kafka idle partition and watermark

[morin . david . bzh]

Hello,

I've faced to this issue in production: 
https://issues.apache.org/jira/browse/FLINK-5479
One topic contains idle partition and all pipeline is quite fucked up. I've 
used aggregation based on these watermarks and the trigger is never launched.
is it possible to define a workaround in waiting the 1.8.0 release that will 
fix this issue ?

Thanks in advance

Here after the code:
kafkaStream.assignTimestampsAndWatermarks(new 
AscendingTimestampExtractor<MyEvent>() {
    @Override
    public long extractAscendingTimestamp(MyEvent element) {
        LOG.debug("Timestamp event in Kafka: {}", element.getTimestamp());
        return Long.parseLong(element.getTimestamp());
    }
});