Class SynchronizedRequestHandler

Constructor Detail

• SynchronizedRequestHandler

  public SynchronizedRequestHandler()

Method Detail

• handleRequest

  public boolean handleRequest(VaadinSession session,
                               VaadinRequest request,
                               VaadinResponse response)
                        throws IOException

  Description copied from interface: RequestHandler

  Called when a request needs to be handled. If a response is written, this method should return true to indicate that no more request handlers should be invoked for the request.

  Note that request handlers by default do not lock the session. If you are using VaadinSession or anything inside the VaadinSession you must ensure the session is locked. This can be done by extending SynchronizedRequestHandler or by using VaadinSession.accessSynchronously(Command) or UI.accessSynchronously(Command).

  Specified by:

  handleRequest in interface RequestHandler

  Parameters:

  session - The session for the request

  request - The request to handle

  response - The response object to which a response can be written.

  Returns:

  true if a response has been written and no further request handlers should be called, otherwise false

  Throws:

  IOException - If an IO error occurred

• synchronizedHandleRequest

  public abstract boolean synchronizedHandleRequest(VaadinSession session,
                                                    VaadinRequest request,
                                                    VaadinResponse response)
                                             throws IOException

  Identical to handleRequest(VaadinSession, VaadinRequest, VaadinResponse) except the VaadinSession is locked before this is called and unlocked after this has completed.

  Parameters:

  session - The session for the request

  request - The request to handle

  response - The response object to which a response can be written.

  Returns:

  true if a response has been written and no further request handlers should be called, otherwise false

  Throws:

  IOException - If an IO error occurred

  See Also:

  handleRequest(VaadinSession, VaadinRequest, VaadinResponse)

• canHandleRequest

  protected boolean canHandleRequest(VaadinRequest request)

  Check whether a request may be handled by this handler. This can be used as an optimization to avoid locking the session just to investigate some method property. The default implementation just returns true which means that all requests will be handled by calling synchronizedHandleRequest(VaadinSession, VaadinRequest, VaadinResponse) with the session locked.

  Parameters:

  request - the request to handle

  Returns:

  true if the request handling should continue once the session has been locked; false if there's no need to lock the session since the request would still not be handled.