sunlabs.brazil.session
Class SessionManager

java.lang.Object
  sunlabs.brazil.session.SessionManager (view source)

Direct Known Subclasses:

CacheManager

public class SessionManager
extends Object

The SessionManager associates an object with a Session ID to give Handlers the ability to maintain state that lasts for the duration of a session instead of just for the duration of a request.

The SessionManager operates as a bag of globally accessible resources. Existing subclasses of the SessionManager also provide persistence, that is, a way to recover these resources even if the server process is terminated and later restarted, to get back to the state things were in.

A session manager is like a Dictionary only with fewer guarantees. Enumeration is not possible, and a "get" might return null even if there was a previous "put", so users should be prepared to handle that case.

Unlike a typical dictionary, a session manager uses two keys to identify to identify each resource. The first key, by convention, represents a client session id. The second (or resource) key is chosen to identify the resource within a session.

Care should be used when choosing resource keys, as they are global to a JVM, which may have several unrelated Brazil servers running at once. Sharing session manager resources between servers can cause unexpected behavior if done unintentionally.

Existing session manager implementations arrange for session resources that are Java Properties to be saved across restarts of the JVM, and should be used when practical.

Constructor Summary

SessionManager()

Method Summary

static Object	get(Object session, Object ident) get an object from the session manager.
static Object	getSession(Object session, Object ident, Class type) Returns the object associated with the given Session ID.
static void	put(Object session, Object ident, Object data) put an object into the session manager.
static void	remove(Object session, Object ident) Remove an object from the session manager.
static void	setSessionManager(SessionManager mgr) Installs the given SessionManager object as the default session manager to be invoked when getSession is called.

Methods inherited from class java.lang.Object

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

Constructor Detail

SessionManager

public SessionManager()

Method Detail

setSessionManager

public static void setSessionManager(SessionManager mgr)

Installs the given SessionManager object as the default session manager to be invoked when getSession is called.

Parameters:

mgr - The SessionManager object.

getSession

public static Object getSession(Object session,
                                Object ident,
                                Class type)

Returns the object associated with the given Session ID. Passing in the same (hash-key equivalent) Session ID will return the same object. This convenience method reflects common usage.

Parameters:

session - The Session ID for the persistent session information. If the session does not exist, a new one is created.

ident - An arbitray identifier used to determine which object (associated with the given session) the caller wants.

type - The Class of the object to create. If the given session and ident did not specify an existing object, a new one is created by calling newInstance based on the type. If null, then this method returns null if the object didn't exist, instead of allocating a new object.

Returns:

an object of type type, or null if the object doesn't exist and type is null.

get

public static Object get(Object session,
                         Object ident)

get an object from the session manager. This static method will dispatch to the currently installed SessionManager instance.

put

public static void put(Object session,
                       Object ident,
                       Object data)

put an object into the session manager. This static method will dispatch to the currently installed SessionManager instance.

remove

public static void remove(Object session,
                          Object ident)

Remove an object from the session manager. This static method will dispatch to the currently installed SessionManager instance.