Package org.jgrapes.http

Class LanguageSelector

java.lang.Object

org.jgrapes.core.internal.ComponentVertex

org.jgrapes.core.Component

org.jgrapes.http.LanguageSelector

All Implemented Interfaces:

Iterable<ComponentType>, Channel, ComponentType, Eligible, Manager

public class LanguageSelector
extends Component

A component that attempts to derive information about language preferences from requests in the specified scope (usually “/”) and make them available as a LanguageSelector.Selection object associated with the request event using Selection.class as association identifier.

The component first checks if the event has an associated Session and whether that session has a value with key Selection.class. If such an entry exists, its value is assumed to be a LanguageSelector.Selection object which is (re-)used for all subsequent operations. Else, a new LanguageSelector.Selection object is created (and associated with the session, if a session exists).

If the LanguageSelector.Selection represents explicitly set values, it is used as result (i.e. as object associated with the event by Selection.class).

Else, the selector tries to derive the language preferences from the request. It first checks for a cookie with the specified name (see cookieName()). If a cookie is found, its value is used to set the preferred locales. If no cookie is found, the values derived from the Accept-Language header are set as fall-backs.

Whenever the language preferences change (see LanguageSelector.Selection.prefer(Locale)), a cookie with the specified name and a path value set to the scope is created and added to the request’s response. This new cookie is then sent with the response to the browser.

Note that this scheme does not work in a SPA where browser and server only communicate over a WebSocket.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final class	LanguageSelector.Selection	Represents a locale selection.

Nested classes/interfaces inherited from interface org.jgrapes.core.Channel

Channel.Default

Field Summary

Fields inherited from class org.jgrapes.core.Component

logger

Fields inherited from interface org.jgrapes.core.Channel

BROADCAST, SELF

Constructor Summary

Constructors

Constructor	Description
LanguageSelector()	Creates a new language selector component with its channel set to itself and the scope set to “/”.
LanguageSelector(String scope)	Creates a new language selector component with its channel set to itself and the scope set to the given value.
LanguageSelector(Channel componentChannel)	Creates a new language selector component with its channel set to the given channel and the scope to “/”.
LanguageSelector(Channel componentChannel, String scope)	Creates a new language selector component with its channel set to the given channel and the scope to the given scope.
LanguageSelector(Channel componentChannel, String scope, int priority)	Creates a new language selector component with its channel set to the given channel and the scope to the given scope.

Method Summary

Modifier and Type	Method	Description
static Locale	associatedLocale(Associator assoc)	Convenience method to retrieve a locale from an associator.
Duration	cookieMaxAge()	Returns the max age of the cookie used to store the preferences.
String	cookieName()	Returns the cookie name.
void	onProtocolSwitchAccepted(ProtocolSwitchAccepted event, IOSubchannel channel)	Handles a procotol switch by associating the language selection with the channel.
void	onRequest(Request.In event)	Associates the event with a LanguageSelector.Selection object using Selection.class as association identifier.
Converters.SameSiteAttribute	sameSiteAttribute()	Returns the value of the same site attribute.
LanguageSelector	setCookieMaxAge(Duration maxAge)	Sets the max age of the cookie used to store the preferences.
LanguageSelector	setCookieName(String cookieName)	Sets the name of the cookie used to store the locale.
LanguageSelector	setSameSiteAttribute(Converters.SameSiteAttribute attribute)	Sets the same site attribute for the locale cookie defaults to Lax.

Methods inherited from class org.jgrapes.core.Component

channel, component, defaultCriterion, isEligibleFor, setName

Methods inherited from class org.jgrapes.core.internal.ComponentVertex

activeEventPipeline, addHandler, attach, channelReplacements, children, componentPath, componentVertex, detach, fire, initComponentsHandlers, iterator, name, newEventPipeline, newEventPipeline, parent, registerAsGenerator, root, toString, unregisterAsGenerator

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Methods inherited from interface org.jgrapes.core.Manager

stream

Constructor Details

LanguageSelector

public LanguageSelector()

Creates a new language selector component with its channel set to itself and the scope set to “/”.

The handler’s priority is set to 990.

LanguageSelector

public LanguageSelector(String scope)

Creates a new language selector component with its channel set to itself and the scope set to the given value.

The handler’s priority is set to 990.

Parameters:

scope - the scope

LanguageSelector

public LanguageSelector(Channel componentChannel)

Creates a new language selector component with its channel set to the given channel and the scope to “/”.

The handler’s priority is set to 990.

Parameters:

componentChannel - the component channel

LanguageSelector

public LanguageSelector(Channel componentChannel,
 String scope)

Creates a new language selector component with its channel set to the given channel and the scope to the given scope.

The handler’s priority is set to 990.

Parameters:

componentChannel - the component channel

scope - the scope

LanguageSelector

public LanguageSelector(Channel componentChannel,
 String scope,
 int priority)

Creates a new language selector component with its channel set to the given channel and the scope to the given scope.

The handler’s priority is set to the given value.

Parameters:

componentChannel - the component channel

scope - the scope

priority - the priority

Method Details

setCookieName

public LanguageSelector setCookieName(String cookieName)

Sets the name of the cookie used to store the locale.

Parameters:

cookieName - the cookie name to use

Returns:

the locale selector for easy chaining

cookieName

public String cookieName()

Returns the cookie name.

Defaults to the class name.

Returns:

the cookie name

setCookieMaxAge

public LanguageSelector setCookieMaxAge(Duration maxAge)

Sets the max age of the cookie used to store the preferences.

Defaults to one year.

Parameters:

maxAge - the max age

Returns:

the language selector

See Also:

• HttpCookie.setMaxAge(long)

cookieMaxAge

public Duration cookieMaxAge()

Returns the max age of the cookie used to store the preferences.

Returns:

the duration

setSameSiteAttribute

public LanguageSelector setSameSiteAttribute(Converters.SameSiteAttribute attribute)

Sets the same site attribute for the locale cookie defaults to Lax.

Parameters:

attribute - the attribute

Returns:

the language selector

sameSiteAttribute

public Converters.SameSiteAttribute sameSiteAttribute()

Returns the value of the same site attribute.

Returns:

the same site attribute

onRequest

@RequestHandler(dynamic=true)
public void onRequest(Request.In event)

Associates the event with a LanguageSelector.Selection object using Selection.class as association identifier.

Does nothing if the request has already been fulfilled.

Parameters:

event - the event

onProtocolSwitchAccepted

@Handler(priority=1000)
public void onProtocolSwitchAccepted(ProtocolSwitchAccepted event,
 IOSubchannel channel)

Handles a procotol switch by associating the language selection with the channel.

Parameters:

event - the event

channel - the channel

associatedLocale

public static Locale associatedLocale(Associator assoc)

Convenience method to retrieve a locale from an associator.

Parameters:

assoc - the associator

Returns:

the locale