问非阻塞终结点:向调用方返回一个操作ID --想了解您对我的实现的看法吗？

EN

    @GetMapping(path="/nonBlockingEndpoint")
public @ResponseBody ResponseOperation nonBlocking() {

    // Register a new operation
    APIOperationsManager apiOpsManager = APIOperationsManager.getInstance();
    final int operationID = apiOpsManager.registerNewOperation(Constants.OpStatus.PROCESSING);
    ResponseOperation response = new ResponseOperation();

    response.setMessage("Triggered non-blocking call, use the operation id to check status");
    response.setOperationID(operationID);
    response.setOpRes(Constants.OpStatus.PROCESSING);

    CompletableFuture<Boolean> cf = CompletableFuture.supplyAsync(() -> {

        try {
            // Here we will 
            Thread.sleep(10000L);
        } catch (InterruptedException e) {}

        // whatever the return value was
        return true;
    });
    cf.thenRun(() ->{ 
        // We are done with the super long process, so update our Operations Manager
        APIOperationsManager a = APIOperationsManager.getInstance();
        boolean asyncSuccess = false;

        try {asyncSuccess = cf.get();} 
        catch (Exception e) {}

        if(true == asyncSuccess) {
            a.updateOperationStatus(operationID, Constants.OpStatus.OK);
            a.updateOperationMessage(operationID, "success: The long running process has finished and this is your result: SOME RESULT" );
        } 
        else {
            a.updateOperationStatus(operationID, Constants.OpStatus.INTERNAL_ERROR);
            a.updateOperationMessage(operationID, "error: The long running process has failed."); 
        }
    });

    return response;
}

public class APIOperationsManager {

    private static APIOperationsManager instance = null;

    private Vector<Operation> operations;
    private int currentOperationId;

    private static final Logger log = LoggerFactory.getLogger(Application.class);

    protected APIOperationsManager() {}

    public static APIOperationsManager getInstance() {
        if(instance == null) {
            synchronized(APIOperationsManager.class) {
                if(instance == null) {
                    instance = new APIOperationsManager();
                    instance.operations = new Vector<Operation>();
                    instance.currentOperationId = 1;
                }
            }
        }
        return instance;
    }


    public synchronized int registerNewOperation(OpStatus status) {
        cleanOperationsList();

        currentOperationId = currentOperationId + 1;
        Operation newOperation = new Operation(currentOperationId, status);
        operations.add(newOperation);
        log.info("Registered new Operation to watch: " + newOperation.toString());
        return newOperation.getId();
    }

    public synchronized Operation getOperation(int id) {

        for(Iterator<Operation> iterator = operations.iterator(); iterator.hasNext();) {
            Operation op = iterator.next();
            if(op.getId() == id) {
                return op;
            }
        }

        Operation notFound = new Operation(-1, OpStatus.INTERNAL_ERROR);
        notFound.setCrated(null);

        return notFound;
    }

    public synchronized void updateOperationStatus (int id, OpStatus newStatus) {

        iteration : for(Iterator<Operation> iterator = operations.iterator(); iterator.hasNext();) {
            Operation op = iterator.next();
            if(op.getId() == id) {
                op.setStatus(newStatus);
                log.info("Updated Operation status: " + op.toString());
                break iteration;
            }
        }
    }

    public synchronized void updateOperationMessage (int id, String message) {

        iteration : for(Iterator<Operation> iterator = operations.iterator(); iterator.hasNext();) {
            Operation op = iterator.next();
            if(op.getId() == id) {
                op.setMessage(message);
                log.info("Updated Operation status: " + op.toString());
                break iteration;
            }
        }
    }

    private synchronized void cleanOperationsList() {
        Date now = new Date();

        for(Iterator<Operation> iterator = operations.iterator(); iterator.hasNext();) {
            Operation op = iterator.next();
            if((now.getTime() - op.getCrated().getTime()) >= Constants.MIN_HOLD_DURATION_OPERATIONS ) {
                log.info("Removed operation from watchlist: " + op.toString());
                iterator.remove();
            }
        }
    }
}