@Override
    public ComplexEventChunk<StateEvent> tryUpdate(ComplexEventChunk<StateEvent> updatingOrAddingEventChunk,
                                                   Object storeEvents, InMemoryCompiledUpdateSet compiledUpdateSet,
                                                   AddingStreamEventExtractor addingStreamEventExtractor) {

        updatingOrAddingEventChunk.reset();
        ComplexEventChunk<StateEvent> failedEventChunk = new ComplexEventChunk<>
                ();
        while (updatingOrAddingEventChunk.hasNext()) {
            StateEvent updateOrAddingEvent = updatingOrAddingEventChunk.next();
            try {
                boolean updated = false;
                if (((Collection<StreamEvent>) storeEvents).size() > 0) {
                    for (StreamEvent storeEvent : ((Collection<StreamEvent>) storeEvents)) {
                        updateOrAddingEvent.setEvent(storeEventPosition, storeEvent);
                        if ((Boolean) expressionExecutor.execute(updateOrAddingEvent)) {
                            for (Map.Entry<Integer, ExpressionExecutor> entry :
                                    compiledUpdateSet.getExpressionExecutorMap().entrySet()) {
                                storeEvent.setOutputData(entry.getValue().execute(updateOrAddingEvent), entry.getKey());
                            }
                            updated = true;
                        }
                    }
                }
                if (!updated) {
                    updatingOrAddingEventChunk.remove();
                    failedEventChunk.add(updateOrAddingEvent);
                }
            } finally {
                updateOrAddingEvent.setEvent(storeEventPosition, null);
            }
        }
        return failedEventChunk;
    }
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