Practical Real-time Data Processing and Analytics

Selecting from patterns

We have created the pattern, and applied it on the data stream - now how do we get the matched events? This can be done by using the following code snippet:

class MyPatternSelectFunction<IN, OUT> implements PatternSelectFunction<IN, OUT> {@Override    public OUT select(Map<String, List<IN>> pattern) {        IN startEvent = pattern.get("start").get(0);        IN endEvent = pattern.get("end").get(0);        return new OUT(startEvent, endEvent);    }}

In is the class on which the event pattern is applied. The Out class is the form of output as an action on matched events.