@Override
    public void update(ComplexEventChunk<StateEvent> updatingEventChunk, Object storeEvents,
                       InMemoryCompiledUpdateSet compiledUpdateSet) {
        SnapshotableStreamEventQueue storeEventQueue = (SnapshotableStreamEventQueue) storeEvents;
        updatingEventChunk.reset();
        while (updatingEventChunk.hasNext()) {
            StateEvent updatingEvent = updatingEventChunk.next();
            try {
                storeEventQueue.reset();
                while (storeEventQueue.hasNext()) {
                    StreamEvent storeEvent = storeEventQueue.next();
                    updatingEvent.setEvent(storeEventPosition, storeEvent);
                    if ((Boolean) expressionExecutor.execute(updatingEvent)) {
                        for (Map.Entry<Integer, ExpressionExecutor> entry :
                                compiledUpdateSet.getExpressionExecutorMap().entrySet()) {
                            Object value = entry.getValue().execute(updatingEvent);
                            storeEvent.setOutputData(value, entry.getKey());
                        }
                        storeEventQueue.overwrite(storeEvent);
                    }
                }
            } finally {
                updatingEvent.setEvent(storeEventPosition, null);
            }
        }
    }
Operator which is related to non-indexed In-memory table operations.
modules/siddhi-core/src/main/java/io/siddhi/core/util/collection/operator/SnapshotableEventQueueOperator.java