com.vaadin.client.communication

Interface PushConnection

All Known Implementing Classes:

AtmospherePushConnection

public interface PushConnection

Represents the client-side endpoint of a bidirectional ("push") communication channel. Can be used to send UIDL request messages to the server and to receive UIDL messages from the server (either asynchronously or as a response to a UIDL request.) Delegates the UIDL handling to the ApplicationConnection.

Since:

7.1

Author:

Vaadin Ltd

Method Summary

Modifier and Type	Method and Description
void	disconnect(com.google.gwt.user.client.Command command) Closes the push connection.
String	getTransportType() Returns a human readable string representation of the transport type used to communicate with the server.
void	init(ApplicationConnection connection, UIState.PushConfigurationState pushConfigurationState) Two-phase construction to allow using GWT.create().
boolean	isActive() Checks whether this push connection is in a state where it can push messages to the server.
boolean	isBidirectional() Checks whether this push connection should be used for communication in both directions or if an XHR should be used for client to server communication.
void	push(elemental.json.JsonObject payload) Pushes a message to the server.

Method Detail

init

void init(ApplicationConnection connection,
          UIState.PushConfigurationState pushConfigurationState)

Two-phase construction to allow using GWT.create().

Parameters:

connection - The ApplicationConnection

push

void push(elemental.json.JsonObject payload)

Pushes a message to the server. Will throw an exception if the connection is not active (see isActive()).

Implementation detail: If the push connection is not connected and the message can thus not be sent, the implementation must call ConnectionStateHandler.pushNotConnected(JsonObject), which will retry the send later.

This method must not be called if the push connection is not bidirectional (if isBidirectional() returns false)

Parameters:

payload - the payload to push

Throws:

IllegalStateException - if this connection is not active

See Also:

isActive()

isActive

boolean isActive()

Checks whether this push connection is in a state where it can push messages to the server. A connection is active until disconnect(Command) has been called.

Returns:

true if this connection can accept new messages; false if this connection is disconnected or disconnecting.

disconnect

void disconnect(com.google.gwt.user.client.Command command)

Closes the push connection. To ensure correct message delivery order, new messages should not be sent using any other channel until it has been confirmed that all messages pending for this connection have been delivered. The provided command callback is invoked when messages can be passed using some other communication channel.

After this method has been called, isActive() returns false. Calling this method for a connection that is no longer active will throw an exception.

Parameters:

command - callback command invoked when the connection has been properly disconnected

Throws:

IllegalStateException - if this connection is not active

getTransportType

String getTransportType()

Returns a human readable string representation of the transport type used to communicate with the server.

Returns:

A human readable string representation of the transport type

Since:

7.1

isBidirectional

boolean isBidirectional()

Checks whether this push connection should be used for communication in both directions or if an XHR should be used for client to server communication. A bidirectional push connection must be able to reliably inform about its connection state.

Returns:

true if the push connection should be used for messages in both directions, false if it should only be used for server to client messages

Since:

7.6