net.contextfw.web.commons.cloud.session.CloudSession Maven / Gradle / Ivy
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package net.contextfw.web.commons.cloud.session;
import net.contextfw.web.application.configuration.Configuration;
import net.contextfw.web.application.configuration.SettableProperty;
import net.contextfw.web.application.configuration.TemporalProperty;
/**
* A common interface for cloud based sessions.
*
*
* Cloud session is a session handling, where session data is kept serialized on
* database and allows multiple nodes to access same data in common way.
*
*
* Session is a simple key/value-store and supports basic CRUD-operations.
* Object are serialized and deserialized, so all kind of structures can be
* stored in transparent way.
*
*
* When values are fetched or stored, operations are cached by default and are
* synced to database when session is closed. In this way, database connections
* are minimized. For all CRUD-methods there exists also a non-cached variant if
* that is needed.
*
*
* Opening and closing session
*
* It is best to handle opening and closing through LifecycleListener and there
* exists a ready made listener CloudSessionLifecycleListener for it.
*
* By default session is opened in lazy-mode where session cookie and data
* structures are created only when needed. This minifies unnecessary session
* creations.
*
* Opening session in existing mode
*
* Sometimes it is necessary to open session in such mode that it must exist in
* order to be effective. This is important especially in applications that poll
* server frequently. In essence frequent polling may prevent session
* expiration.
*
* The CloudSessionLifecycleListener is configured in such way that if remote
* method is also annotated with
* @CloudSessionOpenMode(OpenMode.EXISTING), an existing session is
* required and session expiration is not altered.
*
* @author [email protected]
*/
public interface CloudSession {
/**
* Defines the the name of the cookie used to hold session handle.
*/
SettableProperty COOKIE_NAME =
Configuration.createProperty(String.class,
CloudSession.class.getName() + ".cookieName");
/**
* Defines the maximum inactivity for session before it is expired.
*/
TemporalProperty MAX_INACTIVITY =
Configuration.createTemporalProperty(
CloudSession.class.getName() + ".maxInactivity");
/**
* Closes session and syncs all cached data to database.
*/
void closeSession();
/**
* Expires session and removes possible cookies and database structures.
*/
void expireSession();
/**
* Fetches a value for given type.
*
*
* If type has been fetched before it is taken from local cache.
*
* @param type
* The type to be fetched.
* @return
* Corresponding value or null if value does not exist.
*/
T get(Class type);
/**
*
* @param type
* @param nonCached
* @return
*
* *
*
* If type has been fetched before it is taken from local cache.
*
* @param type
* The type to be fetched.
* @return
* Corresponding value or null if value does not exist.
*
*/
T get(Class type, boolean nonCached);
/**
*
* @param key
* @param type
* @return
*/
T get(String key, Class type);
T get(String key, Class type, boolean nonCached);
void openSession(OpenMode mode);
void remove(Class type);
void remove(Class type, boolean nonCached);
void remove(String key);
void remove(String key, boolean nonCached);
/**
* Sets a value to the cloud session
*
*
* This method creates a key from values class name and dispatches it to
* set(String key, Object value). This method is nice shortcut
* for objects that are stored as "singletons" to session.
*
*
* @param value
* The value to be set
*/
void set(Object value);
void set(Object value, boolean nonCached);
/**
* Sets a value with given key to the cloud session.
*
*
* The setting of the value is immediately seen by the session through
* get(), but setting the actual value to storage is delayed until session
* is closed.
*
*
* If value has been removed or set earlier to different value, those
* changes will be overriden.
*
*
* @param key
* The key to distinguish value
* @param value
* The value to be set. If null is passed, the value
* is removed.
*/
void set(String key, Object value);
void set(String key, Object value, boolean nonCached);
}