@Override
    public StreamEvent find(StateEvent matchingEvent, Object storeEvents, StreamEventCloner storeEventCloner) {

        ComplexEventChunk<StreamEvent> returnEventChunk = new ComplexEventChunk<>();
        for (StreamEvent storeEvent : (Collection<StreamEvent>) storeEvents) {
            matchingEvent.setEvent(storeEventPosition, storeEvent);
            if ((Boolean) expressionExecutor.execute(matchingEvent)) {
                returnEventChunk.add(storeEventCloner.copyStreamEvent(storeEvent));
            }
            matchingEvent.setEvent(storeEventPosition, null);
        }
        return returnEventChunk.getFirst();

    }
Operator which is related to non-indexed In-memory table operations.
modules/siddhi-core/src/main/java/io/siddhi/core/util/collection/operator/CollectionOperator.java