com.vaadin.flow.server.communication

Class UidlRequestHandler

java.lang.Object

com.vaadin.flow.server.SynchronizedRequestHandler

com.vaadin.flow.server.communication.UidlRequestHandler

All Implemented Interfaces:

RequestHandler, SessionExpiredHandler, Serializable

public class UidlRequestHandler
extends SynchronizedRequestHandler
implements SessionExpiredHandler

Processes a UIDL request from the client. Uses ServerRpcHandler to execute client-to-server RPC invocations and UidlWriter to write state changes and client RPC calls back to the client.

Since:

1.0

Author:

Vaadin Ltd

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static String	UIDL_PATH

Constructor Summary

Constructors

Constructor and Description
UidlRequestHandler()

Method Summary

Modifier and Type	Method and Description
protected boolean	canHandleRequest(VaadinRequest request) Check whether a request may be handled by this handler.
static void	commitJsonResponse(VaadinResponse response, String json) Commit the JSON response.
protected ServerRpcHandler	createRpcHandler() Creates the ServerRpcHandler to use.
boolean	handleSessionExpired(VaadinRequest request, VaadinResponse response) Called when the a session expiration has occurred and a notification needs to be sent to the user.
boolean	synchronizedHandleRequest(VaadinSession session, VaadinRequest request, VaadinResponse response) Identical to SynchronizedRequestHandler.handleRequest(VaadinSession, VaadinRequest, VaadinResponse) except the VaadinSession is locked before this is called and unlocked after this has completed.

Methods inherited from class com.vaadin.flow.server.SynchronizedRequestHandler

handleRequest

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface com.vaadin.flow.server.RequestHandler

handleRequest

Field Detail

UIDL_PATH

public static final String UIDL_PATH

See Also:

Constant Field Values

Constructor Detail

UidlRequestHandler

public UidlRequestHandler()

Method Detail

canHandleRequest

protected boolean canHandleRequest(VaadinRequest request)

Description copied from class: SynchronizedRequestHandler

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 SynchronizedRequestHandler.synchronizedHandleRequest(VaadinSession, VaadinRequest, VaadinResponse) with the session locked.

Overrides:

canHandleRequest in class SynchronizedRequestHandler

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.

createRpcHandler

protected ServerRpcHandler createRpcHandler()

Creates the ServerRpcHandler to use.

Returns:

the ServerRpcHandler to use

synchronizedHandleRequest

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

Description copied from class: SynchronizedRequestHandler

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

Specified by:

synchronizedHandleRequest in class SynchronizedRequestHandler

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:

SynchronizedRequestHandler.handleRequest(VaadinSession, VaadinRequest, VaadinResponse)

handleSessionExpired

public boolean handleSessionExpired(VaadinRequest request,
                                    VaadinResponse response)
                             throws IOException

Description copied from interface: SessionExpiredHandler

Called when the a session expiration has occurred and a notification needs to be sent to the user. If a response is written, this method should return true to indicate that no more SessionExpiredHandler handlers should be invoked for the request.

Specified by:

handleSessionExpired in interface SessionExpiredHandler

Parameters:

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

commitJsonResponse

public static void commitJsonResponse(VaadinResponse response,
                                      String json)
                               throws IOException

Commit the JSON response. We can't write immediately to the output stream as we want to write only a critical notification if something goes wrong during the response handling.

Parameters:

response - The response to write to

json - The JSON to write

Throws:

IOException - If there was an exception while writing to the output