com.vaadin.server.communication

Class UIInitHandler

java.lang.Object

com.vaadin.server.SynchronizedRequestHandler

com.vaadin.server.communication.UIInitHandler

All Implemented Interfaces:

RequestHandler, Serializable

Direct Known Subclasses:

ServletUIInitHandler

public abstract class UIInitHandler
extends SynchronizedRequestHandler

Handles an initial request from the client to initialize a UI.

Since:

7.1

Author:

Vaadin Ltd

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static String	BROWSER_DETAILS_PARAMETER

Constructor Summary

Constructors

Constructor and Description
UIInitHandler()

Method Summary

Modifier and Type	Method and Description
protected boolean	canHandleRequest(VaadinRequest request) Check whether a request may be handled by this handler.
protected String	getEmbedId(VaadinRequest request) Constructs an embed id based on information in the request.
protected String	getInitialUidl(VaadinRequest request, UI uI) Generates the initial UIDL message that can e.g.
protected abstract boolean	isInitRequest(VaadinRequest request)
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.server.SynchronizedRequestHandler

handleRequest

Methods inherited from class java.lang.Object

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

Field Detail

BROWSER_DETAILS_PARAMETER

public static final String BROWSER_DETAILS_PARAMETER

See Also:

Constant Field Values

Constructor Detail

UIInitHandler

public UIInitHandler()

Method Detail

isInitRequest

protected abstract boolean isInitRequest(VaadinRequest request)

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.

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)

getEmbedId

protected String getEmbedId(VaadinRequest request)

Constructs an embed id based on information in the request.

Parameters:

request - the request to get embed information from

Returns:

the embed id, or null if id is not available.

Since:

7.2

See Also:

UI.getEmbedId()

getInitialUidl

protected String getInitialUidl(VaadinRequest request,
                                UI uI)
                         throws IOException

Generates the initial UIDL message that can e.g. be included in a html page to avoid a separate round trip just for getting the UIDL.

Parameters:

request - the request that caused the initialization

uI - the UI for which the UIDL should be generated

Returns:

a string with the initial UIDL message

Throws:

IOException