com.vaadin.server
Class VaadinSession

java.lang.Object
  com.vaadin.server.VaadinSession

All Implemented Interfaces:

java.io.Serializable, java.util.EventListener, javax.servlet.http.HttpSessionBindingListener

Direct Known Subclasses:

VaadinPortletSession

public class VaadinSession
extends java.lang.Object
implements javax.servlet.http.HttpSessionBindingListener, java.io.Serializable

Contains everything that Vaadin needs to store for a specific user. This is typically stored in a HttpSession or PortletSession, but others storage mechanisms might also be used.

Everything inside a VaadinSession should be serializable to ensure compatibility with schemes using serialization for persisting the session data.

Since:

7.0.0

Author:

Vaadin Ltd

See Also:

Serialized Form

Nested Class Summary

static class

VaadinSession.FutureAccess Encapsulates a Runnable submitted using access(Runnable).

Field Summary

protected WebBrowser	browser
static java.lang.String	UI_PARAMETER The name of the parameter that is by default used in e.g.

Constructor Summary

VaadinSession(VaadinService service)
Creates a new VaadinSession tied to a VaadinService.

Method Summary

java.util.concurrent.Future<java.lang.Void>	access(java.lang.Runnable runnable) Provides exclusive access to this session from outside a request handling thread.
void	accessSynchronously(java.lang.Runnable runnable) Locks this session and runs the provided Runnable right away.
void	addBootstrapListener(BootstrapListener listener) Adds a listener that will be invoked when the bootstrap HTML is about to be generated.
void	addRequestHandler(RequestHandler handler) Adds a request handler to this session.
void	addUI(UI ui) Adds an initialized UI to this session.
void	addUIProvider(UIProvider uiProvider) Adds a UI provider to this session.
void	close() Sets this session to be closed and all UI state to be discarded at the end of the current request, or at the end of the next request if there is no ongoing one.
java.lang.String	createConnectorId(ClientConnector connector) Deprecated. As of 7.0. Will likely change or be removed in a future version
<T> T	getAttribute(java.lang.Class<T> type) Gets a stored attribute value.
java.lang.Object	getAttribute(java.lang.String name) Gets a stored attribute value.
WebBrowser	getBrowser() Deprecated. As of 7.0, use Page.getWebBrowser() instead.
LegacyCommunicationManager	getCommunicationManager() Deprecated. As of 7.0. Will likely change or be removed in a future version
DeploymentConfiguration	getConfiguration() Gets the configuration for this session
ConverterFactory	getConverterFactory() Gets the ConverterFactory used to locate a suitable Converter for fields in the session.
java.lang.String	getCsrfToken() Gets the CSRF token (aka double submit cookie) that is used to protect against Cross Site Request Forgery attacks.
long	getCumulativeRequestDuration()
static VaadinSession	getCurrent() Gets the currently used session.
ErrorHandler	getErrorHandler() Gets the session's error handler.
static VaadinSession	getForSession(VaadinService service, WrappedSession underlyingSession) Deprecated. As of 7.0. Should be moved to a separate session storage class some day.
GlobalResourceHandler	getGlobalResourceHandler(boolean createOnDemand) Gets this session's global resource handler that takes care of serving connector resources that are not served by any single connector because e.g.
long	getLastRequestDuration()
long	getLastRequestTimestamp() Returns the time when the last request was serviced in this session.
java.util.Locale	getLocale() Gets the default locale for this session.
java.util.concurrent.locks.Lock	getLockInstance() Gets the Lock instance that is used for protecting the data of this session from concurrent access.
int	getNextUIid() Creates a new unique id for a UI.
java.util.Queue<VaadinSession.FutureAccess>	getPendingAccessQueue() Gets the queue of tasks submitted using access(Runnable).
java.util.Map<java.lang.String,java.lang.Integer>	getPreserveOnRefreshUIs() Gets the mapping from window.name to UI id for UIs that are should be retained on refresh.
java.util.Collection<RequestHandler>	getRequestHandlers() Gets the request handlers that are registered to the session.
VaadinService	getService()
WrappedSession	getSession() Gets the underlying session to which this service session is currently associated.
UI	getUIById(int uiId) Returns a UI with the given id.
java.util.List<UIProvider>	getUIProviders() Gets the UI providers configured for this session.
java.util.Collection<UI>	getUIs() Gets all the UIs of this session.
boolean	hasLock() Checks if the current thread has exclusive access to this VaadinSession
boolean	isClosing() Returns whether this session is marked to be closed.
void	lock() Locks this session to protect its data from concurrent access.
void	modifyBootstrapResponse(BootstrapResponse response) Deprecated. As of 7.0. Will likely change or be removed in a future version
void	removeBootstrapListener(BootstrapListener listener) Remove a bootstrap listener that was previously added.
void	removeFromSession(VaadinService service) Deprecated. As of 7.0. Should be moved to a separate session storage class some day.
void	removeRequestHandler(RequestHandler handler) Removes a request handler from the session.
void	removeUI(UI ui) Called by the framework to remove an UI instance from the session because it has been closed.
void	removeUIProvider(UIProvider uiProvider) Removes a UI provider association from this session.
<T> void	setAttribute(java.lang.Class<T> type, T value) Stores a value in this service session.
void	setAttribute(java.lang.String name, java.lang.Object value) Stores a value in this service session.
void	setCommunicationManager(LegacyCommunicationManager communicationManager)
void	setConfiguration(DeploymentConfiguration configuration)
void	setConverterFactory(ConverterFactory converterFactory) Sets the ConverterFactory used to locate a suitable Converter for fields in the session.
static void	setCurrent(VaadinSession session) Sets the thread local for the current session.
void	setErrorHandler(ErrorHandler errorHandler) Sets the session error handler.
void	setLastRequestDuration(long time) Sets the time spent servicing the last request in the session and updates the total time spent servicing requests in this session.
void	setLastRequestTimestamp(long timestamp) Sets the time when the last UIDL request was serviced in this session.
void	setLocale(java.util.Locale locale) Sets the default locale for this session.
void	storeInSession(VaadinService service, WrappedSession session) Deprecated. As of 7.0. Should be moved to a separate session storage class some day.
void	unlock() Unlocks this session.
void	valueBound(javax.servlet.http.HttpSessionBindingEvent arg0)
void	valueUnbound(javax.servlet.http.HttpSessionBindingEvent event)

Methods inherited from class java.lang.Object

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

Field Detail

UI_PARAMETER

public static final java.lang.String UI_PARAMETER

The name of the parameter that is by default used in e.g. web.xml to define the name of the default UI class.

See Also:

Constant Field Values

browser

protected WebBrowser browser

Constructor Detail

VaadinSession

public VaadinSession(VaadinService service)

Creates a new VaadinSession tied to a VaadinService.

Parameters:

service - the Vaadin service for the new session

Method Detail

valueBound

public void valueBound(javax.servlet.http.HttpSessionBindingEvent arg0)

Specified by:

valueBound in interface javax.servlet.http.HttpSessionBindingListener

See Also:

HttpSessionBindingListener.valueBound(HttpSessionBindingEvent)

valueUnbound

public void valueUnbound(javax.servlet.http.HttpSessionBindingEvent event)

Specified by:

valueUnbound in interface javax.servlet.http.HttpSessionBindingListener

See Also:

HttpSessionBindingListener.valueUnbound(HttpSessionBindingEvent)

getBrowser

@Deprecated
public WebBrowser getBrowser()

Deprecated. As of 7.0, use Page.getWebBrowser() instead.

Get the web browser associated with this session.

Returns:

the web browser object

getCumulativeRequestDuration

public long getCumulativeRequestDuration()

Returns:

The total time spent servicing requests in this session, in milliseconds.

setLastRequestDuration

public void setLastRequestDuration(long time)

Sets the time spent servicing the last request in the session and updates the total time spent servicing requests in this session.

Parameters:

time - The time spent in the last request, in milliseconds.

getLastRequestDuration

public long getLastRequestDuration()

Returns:

The time spent servicing the last request in this session, in milliseconds.

setLastRequestTimestamp

public void setLastRequestTimestamp(long timestamp)

Sets the time when the last UIDL request was serviced in this session.

Parameters:

timestamp - The time when the last request was handled, in milliseconds since the epoch.

getLastRequestTimestamp

public long getLastRequestTimestamp()

Returns the time when the last request was serviced in this session.

Returns:

The time when the last request was handled, in milliseconds since the epoch.

getSession

public WrappedSession getSession()

Gets the underlying session to which this service session is currently associated.

Returns:

the wrapped session for this context

getCommunicationManager

@Deprecated
public LegacyCommunicationManager getCommunicationManager()

Deprecated. As of 7.0. Will likely change or be removed in a future version

Returns:

getForSession

@Deprecated
public static VaadinSession getForSession(VaadinService service,
                                                     WrappedSession underlyingSession)

Deprecated. As of 7.0. Should be moved to a separate session storage class some day.

Loads the VaadinSession for the given service and WrappedSession from the HTTP session.

Parameters:

service - The service the VaadinSession is associated with

underlyingSession - The wrapped HTTP session for the user

Returns:

A VaadinSession instance for the service, session combination or null if none was found.

removeFromSession

@Deprecated
public void removeFromSession(VaadinService service)

Deprecated. As of 7.0. Should be moved to a separate session storage class some day.

Removes this VaadinSession from the HTTP session.

Parameters:

service - The service this session is associated with

storeInSession

@Deprecated
public void storeInSession(VaadinService service,
                                      WrappedSession session)

Deprecated. As of 7.0. Should be moved to a separate session storage class some day.

Stores this VaadinSession in the HTTP session.

Parameters:

service - The service this session is associated with

session - The HTTP session this VaadinSession should be stored in

setCommunicationManager

public void setCommunicationManager(LegacyCommunicationManager communicationManager)

setConfiguration

public void setConfiguration(DeploymentConfiguration configuration)

getConfiguration

public DeploymentConfiguration getConfiguration()

Gets the configuration for this session

Returns:

the deployment configuration

getLocale

public java.util.Locale getLocale()

Gets the default locale for this session. By default this is the preferred locale of the user using the session. In most cases it is read from the browser defaults.

Returns:

the locale of this session.

setLocale

public void setLocale(java.util.Locale locale)

Sets the default locale for this session. By default this is the preferred locale of the user using the application. In most cases it is read from the browser defaults.

Parameters:

locale - the Locale object.

getErrorHandler

public ErrorHandler getErrorHandler()

Gets the session's error handler.

Returns:

the current error handler

setErrorHandler

public void setErrorHandler(ErrorHandler errorHandler)

Sets the session error handler.

Parameters:

errorHandler -

getConverterFactory

public ConverterFactory getConverterFactory()

Gets the ConverterFactory used to locate a suitable Converter for fields in the session. See setConverterFactory(ConverterFactory) for more details

Returns:

The converter factory used in the session

setConverterFactory

public void setConverterFactory(ConverterFactory converterFactory)

Sets the ConverterFactory used to locate a suitable Converter for fields in the session.

The ConverterFactory is used to find a suitable converter when binding data to a UI component and the data type does not match the UI component type, e.g. binding a Double to a TextField (which is based on a String).

The Converter for an individual field can be overridden using AbstractField.setConverter(Converter) and for individual property ids in a Table using Table.setConverter(Object, Converter).

The converter factory must never be set to null.

Parameters:

converterFactory - The converter factory used in the session

addRequestHandler

public void addRequestHandler(RequestHandler handler)

Adds a request handler to this session. Request handlers can be added to provide responses to requests that are not handled by the default functionality of the framework.

Handlers are called in reverse order of addition, so the most recently added handler will be called first.

Parameters:

handler - the request handler to add

Since:

7.0

See Also:

removeRequestHandler(RequestHandler)

removeRequestHandler

public void removeRequestHandler(RequestHandler handler)

Removes a request handler from the session.

Parameters:

handler - the request handler to remove

Since:

7.0

getRequestHandlers

public java.util.Collection<RequestHandler> getRequestHandlers()

Gets the request handlers that are registered to the session. The iteration order of the returned collection is the same as the order in which the request handlers will be invoked when a request is handled.

Returns:

a collection of request handlers, with the iteration order according to the order they would be invoked

Since:

7.0

See Also:

addRequestHandler(RequestHandler), removeRequestHandler(RequestHandler)

getCurrent

public static VaadinSession getCurrent()

Gets the currently used session. The current session is automatically defined when processing requests to the server and in threads started at a point when the current session is defined (see InheritableThreadLocal). In other cases, (e.g. from background threads started in some other way), the current session is not automatically defined.

Returns:

the current session instance if available, otherwise null

Since:

7.0

See Also:

setCurrent(VaadinSession)

setCurrent

public static void setCurrent(VaadinSession session)

Sets the thread local for the current session. This method is used by the framework to set the current session whenever a new request is processed and it is cleared when the request has been processed.

The application developer can also use this method to define the current session outside the normal request handling and treads started from request handling threads, e.g. when initiating custom background threads.

Parameters:

session -

Since:

7.0

See Also:

getCurrent(), ThreadLocal

getUIs

public java.util.Collection<UI> getUIs()

Gets all the UIs of this session. This includes UIs that have been requested but not yet initialized. UIs that receive no heartbeat requests from the client are eventually removed from the session.

Returns:

a collection of UIs belonging to this application

Since:

7.0

createConnectorId

@Deprecated
public java.lang.String createConnectorId(ClientConnector connector)

Deprecated. As of 7.0. Will likely change or be removed in a future version

Generate an id for the given Connector. Connectors must not call this method more than once, the first time they need an id.

Parameters:

connector - A connector that has not yet been assigned an id.

Returns:

A new id for the connector

getUIById

public UI getUIById(int uiId)

Returns a UI with the given id.

This is meant for framework internal use.

Parameters:

uiId - The UI id

Returns:

The UI with the given id or null if not found

hasLock

public boolean hasLock()

Checks if the current thread has exclusive access to this VaadinSession

Returns:

true if the thread has exclusive access, false otherwise

addBootstrapListener

public void addBootstrapListener(BootstrapListener listener)

Adds a listener that will be invoked when the bootstrap HTML is about to be generated. This can be used to modify the contents of the HTML that loads the Vaadin application in the browser and the HTTP headers that are included in the response serving the HTML.

Parameters:

listener - the bootstrap listener to add

See Also:

BootstrapListener.modifyBootstrapFragment(BootstrapFragmentResponse), BootstrapListener.modifyBootstrapPage(BootstrapPageResponse)

removeBootstrapListener

public void removeBootstrapListener(BootstrapListener listener)

Remove a bootstrap listener that was previously added.

Parameters:

listener - the bootstrap listener to remove

See Also:

addBootstrapListener(BootstrapListener)

modifyBootstrapResponse

@Deprecated
public void modifyBootstrapResponse(BootstrapResponse response)

Deprecated. As of 7.0. Will likely change or be removed in a future version

Fires a bootstrap event to all registered listeners. There are currently two supported events, both inheriting from BootstrapResponse: BootstrapFragmentResponse and BootstrapPageResponse.

Parameters:

response - the bootstrap response event for which listeners should be fired

removeUI

public void removeUI(UI ui)

Called by the framework to remove an UI instance from the session because it has been closed.

Parameters:

ui - the UI to remove

getGlobalResourceHandler

public GlobalResourceHandler getGlobalResourceHandler(boolean createOnDemand)

Gets this session's global resource handler that takes care of serving connector resources that are not served by any single connector because e.g. because they are served with strong caching or because of legacy reasons.

Parameters:

createOnDemand - true if a resource handler should be initialized if there is no handler associated with this application. false if null should be returned if there is no registered handler.

Returns:

this session's global resource handler, or null if there is no handler and the createOnDemand parameter is false.

Since:

7.0.0

getLockInstance

public java.util.concurrent.locks.Lock getLockInstance()

Gets the Lock instance that is used for protecting the data of this session from concurrent access.

The Lock can be used to gain more control than what is available only using lock() and unlock(). The returned instance is not guaranteed to support any other features of the Lock interface than Lock.lock() and Lock.unlock().

Returns:

the Lock that is used for synchronization, never null

See Also:

lock(), Lock

lock

public void lock()

Locks this session to protect its data from concurrent access. Accessing the UI state from outside the normal request handling should always lock the session and unlock it when done. The preferred way to ensure locking is done correctly is to wrap your code using UI.access(Runnable) (or access(Runnable) if you are only touching the session and not any UI), e.g.:

 myUI.access(new Runnable() {
     @Override
     public void run() {
         // Here it is safe to update the UI.
         // UI.getCurrent can also be used
         myUI.getContent().setCaption("Changed safely");
     }
 });
 

If you for whatever reason want to do locking manually, you should do it like:

 session.lock();
 try {
     doSomething();
 } finally {
     session.unlock();
 }
 

This method will block until the lock can be retrieved.

getLockInstance() can be used if more control over the locking is required.

See Also:

unlock(), getLockInstance(), hasLock()

unlock

public void unlock()

Unlocks this session. This method should always be used in a finally block after lock() to ensure that the lock is always released.

For UIs in this session that have its push mode set to automatic, pending changes will be pushed to their respective clients.

See Also:

lock(), UI.push()

setAttribute

public void setAttribute(java.lang.String name,
                         java.lang.Object value)

Stores a value in this service session. This can be used to associate data with the current user so that it can be retrieved at a later point from some other part of the application. Setting the value to null clears the stored value.

Parameters:

name - the name to associate the value with, can not be null

value - the value to associate with the name, or null to remove a previous association.

See Also:

getAttribute(String)

setAttribute

public <T> void setAttribute(java.lang.Class<T> type,
                             T value)

Stores a value in this service session. This can be used to associate data with the current user so that it can be retrieved at a later point from some other part of the application. Setting the value to null clears the stored value.

The fully qualified name of the type is used as the name when storing the value. The outcome of calling this method is thus the same as if calling

setAttribute(type.getName(), value);

Parameters:

type - the type that the stored value represents, can not be null

value - the value to associate with the type, or null to remove a previous association.

See Also:

getAttribute(Class), setAttribute(String, Object)

getAttribute

public java.lang.Object getAttribute(java.lang.String name)

Gets a stored attribute value. If a value has been stored for the session, that value is returned. If no value is stored for the name, null is returned.

Parameters:

name - the name of the value to get, can not be null.

Returns:

the value, or null if no value has been stored or if it has been set to null.

See Also:

setAttribute(String, Object)

getAttribute

public <T> T getAttribute(java.lang.Class<T> type)

Gets a stored attribute value. If a value has been stored for the session, that value is returned. If no value is stored for the name, null is returned.

The fully qualified name of the type is used as the name when getting the value. The outcome of calling this method is thus the same as if calling

getAttribute(type.getName());

Parameters:

type - the type of the value to get, can not be null.

Returns:

the value, or null if no value has been stored or if it has been set to null.

See Also:

setAttribute(Class, Object), getAttribute(String)

getNextUIid

public int getNextUIid()

Creates a new unique id for a UI.

Returns:

a unique UI id

getPreserveOnRefreshUIs

public java.util.Map<java.lang.String,java.lang.Integer> getPreserveOnRefreshUIs()

Gets the mapping from window.name to UI id for UIs that are should be retained on refresh.

Returns:

the mapping between window names and UI ids for this session.

See Also:

VaadinService#preserveUIOnRefresh(VaadinRequest, UI, UIProvider), PreserveOnRefresh

addUI

public void addUI(UI ui)

Adds an initialized UI to this session.

Parameters:

ui - the initialized UI to add.

addUIProvider

public void addUIProvider(UIProvider uiProvider)

Adds a UI provider to this session.

Parameters:

uiProvider - the UI provider that should be added

removeUIProvider

public void removeUIProvider(UIProvider uiProvider)

Removes a UI provider association from this session.

Parameters:

uiProvider - the UI provider that should be removed

getUIProviders

public java.util.List<UIProvider> getUIProviders()

Gets the UI providers configured for this session.

Returns:

an unmodifiable list of UI providers

getService

public VaadinService getService()

close

public void close()

Sets this session to be closed and all UI state to be discarded at the end of the current request, or at the end of the next request if there is no ongoing one.

After the session has been discarded, any UIs that have been left open will give a Session Expired error and a new session will be created for serving new UIs.

To avoid causing out of sync errors, you should typically redirect to some other page using Page.setLocation(String) to make the browser unload the invalidated UI.

See Also:

SystemMessages.getSessionExpiredCaption()

isClosing

public boolean isClosing()

Returns whether this session is marked to be closed.

Returns:

true if this session is marked to be closed, false otherwise

See Also:

close()

accessSynchronously

public void accessSynchronously(java.lang.Runnable runnable)

Locks this session and runs the provided Runnable right away.

It is generally recommended to use access(Runnable) instead of this method for accessing a session from a different thread as access(Runnable) can be used while holding the lock of another session. To avoid causing deadlocks, this methods throws an exception if it is detected than another session is also locked by the current thread.

This method behaves differently than access(Runnable) in some situations:

• If the current thread is currently holding the lock of this session, accessSynchronously(Runnable) runs the task right away whereas access(Runnable) defers the task to a later point in time.
• If some other thread is currently holding the lock for this session, accessSynchronously(Runnable) blocks while waiting for the lock to be available whereas access(Runnable) defers the task to a later point in time.

Parameters:

runnable - the runnable which accesses the session

Throws:

java.lang.IllegalStateException - if the current thread holds the lock for another session

Since:

7.1

See Also:

lock(), getCurrent(), access(Runnable), UI.accessSynchronously(Runnable)

access

public java.util.concurrent.Future<java.lang.Void> access(java.lang.Runnable runnable)

Provides exclusive access to this session from outside a request handling thread.

The given runnable is executed while holding the session lock to ensure exclusive access to this session. If this session is not locked, the lock will be acquired and the runnable is run right away. If this session is currently locked, the runnable will be run before that lock is released.

RPC handlers for components inside this session do not need to use this method as the session is automatically locked by the framework during RPC handling.

Please note that the runnable might be invoked on a different thread or later on the current thread, which means that custom thread locals might not have the expected values when the runnable is executed. Inheritable values in CurrentInstance will have the same values as when this method was invoked. getCurrent() and VaadinService.getCurrent() are set according to this session before executing the runnable. Non-inheritable CurrentInstance values including VaadinService.getCurrentRequest() and VaadinService.getCurrentResponse() will not be defined.

The returned future can be used to check for task completion and to cancel the task. To help avoiding deadlocks, Future.get() throws an exception if it is detected that the current thread holds the lock for some other session.

Parameters:

runnable - the runnable which accesses the session

Returns:

a future that can be used to check for task completion and to cancel the task

Since:

7.1

See Also:

lock(), getCurrent(), accessSynchronously(Runnable), UI.access(Runnable)

getPendingAccessQueue

public java.util.Queue<VaadinSession.FutureAccess> getPendingAccessQueue()

Gets the queue of tasks submitted using access(Runnable). It is safe to call this method and access the returned queue without holding the session lock.

Returns:

the queue of pending access tasks

Since:

7.1

getCsrfToken

public java.lang.String getCsrfToken()

Gets the CSRF token (aka double submit cookie) that is used to protect against Cross Site Request Forgery attacks.

Returns:

the csrf token string

Since:

7.1