org.apache.brooklyn.rest.util

Class MultiSessionAttributeAdapter

java.lang.Object

org.apache.brooklyn.rest.util.MultiSessionAttributeAdapter

public class MultiSessionAttributeAdapter
extends java.lang.Object

Convenience to assist working with multiple sessions, ensuring requests in different bundles can get a consistent shared view of data.

Any processing that wants to getAttribute(String), setAttribute(String, Object) or removeAttribute(String) in a way that all Brooklyn bundles will see (e.g. authentication, etc) should use the methods in this class, as opposed to calling HttpServletRequest.getSession() then HttpSession.getAttribute(String).

This class will follow heuristics to find a preferred shared session. The heuristics are as follows:

• We look at the Server for a KEY_PREFERRED_SESSION_HANDLER_INSTANCE, and if it has a session with KEY_IS_PREFERRED, we use it
• We look in all session handlers for a session marked as KEY_IS_PREFERRED
• If there is a KEY_PREFERRED_SESSION_HANDLER_INSTANCE at the server, we create a session there (if needed, and if we can, ie we have the request) and mark it (or one already existing there) as KEY_IS_PREFERRED
• If there is no KEY_PREFERRED_SESSION_HANDLER_INSTANCE at the server, we go through all bundles looking for the CXF one and we store that against the Server (this should only happen once, will log warnings if not found)
• Finally we mark the originating session as the KEY_IS_PREFERRED so that it is used in preference to others, including ones at the KEY_PREFERRED_SESSION_HANDLER_INSTANCE, if we were invoked in a way where we couldn't find such a handler (ie no such bundle) and we couldn't create one there

This class may have the occasional quirk if run in parallel but we can live with that, and the danger I think is confined to inconsistent sessions. It logs in that case and other fringe cases.

In future we may wish to make this more configurable, so bundles can specify a priority or a configuration property could specify the preferred bundles and/or context paths. But for now hard-coding CXF is fine.

Obviously code that bypasses this and uses the HttpServletRequest.getSession() will only read/write things in their session, and it won't be visible to requests from other bundles.

Previously we tried sharing sessions across bundles; you'll see in git history the code for that; however it was messy, and ended up being dodgy when we invalidate, and likely very dodgy if the system auto-invalidates (e.g. time- or memory-based expiry), as code there is quite fragile assuming sessions are one-to-one tied to their handlers.

Field Summary

Fields

Modifier and Type	Field and Description
static ConfigKey<java.lang.Integer>	MAX_INACTIVE_INTERVAL
static ConfigKey<java.lang.Long>	MAX_SESSION_AGE

Constructor Summary

Constructors

Constructor and Description
MultiSessionAttributeAdapter(javax.servlet.http.HttpSession preferredSession, javax.servlet.http.HttpSession session)

Method Summary

Modifier and Type	Method and Description
MultiSessionAttributeAdapter	configureWhetherToSetInAll(boolean setAllKnownSessions)
MultiSessionAttributeAdapter	configureWhetherToSetLocalValuesAlso(boolean setLocalValuesAlso)
MultiSessionAttributeAdapter	configureWhetherToSilentlyAcceptLocalOnlyValues(boolean silentlyAcceptLocalOnlyValues)
java.lang.Object	getAttribute(java.lang.String name)
java.lang.String	getId()
javax.servlet.http.HttpSession	getOriginalSession()
javax.servlet.http.HttpSession	getPreferredSession()
static java.lang.String	info(javax.servlet.http.HttpServletRequest r)
static java.lang.String	info(javax.servlet.http.HttpSession s)
static java.lang.String	info(org.eclipse.jetty.server.session.SessionHandler h)
static MultiSessionAttributeAdapter	of(javax.servlet.http.HttpServletRequest r)
static MultiSessionAttributeAdapter	of(javax.servlet.http.HttpServletRequest r, boolean create) May return null iff create is false
static MultiSessionAttributeAdapter	of(javax.servlet.http.HttpSession session) Where the request isn't available, and the preferred session is expected to exist.
void	removeAttribute(java.lang.String name)
MultiSessionAttributeAdapter	resetExpiration()
void	setAttribute(java.lang.String name, java.lang.Object value)

Methods inherited from class java.lang.Object

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

Field Detail

MAX_SESSION_AGE

public static final ConfigKey<java.lang.Long> MAX_SESSION_AGE

MAX_INACTIVE_INTERVAL

public static final ConfigKey<java.lang.Integer> MAX_INACTIVE_INTERVAL

Constructor Detail

MultiSessionAttributeAdapter

public MultiSessionAttributeAdapter(javax.servlet.http.HttpSession preferredSession,
                                    javax.servlet.http.HttpSession session)

Method Detail

of

public static MultiSessionAttributeAdapter of(javax.servlet.http.HttpServletRequest r)

of

public static MultiSessionAttributeAdapter of(javax.servlet.http.HttpServletRequest r,
                                              boolean create)

May return null iff create is false

of

public static MultiSessionAttributeAdapter of(javax.servlet.http.HttpSession session)

Where the request isn't available, and the preferred session is expected to exist. Note we cannot create a new session at the preferred handler without a request.

info

public static java.lang.String info(javax.servlet.http.HttpServletRequest r)

info

public static java.lang.String info(org.eclipse.jetty.server.session.SessionHandler h)

info

public static java.lang.String info(javax.servlet.http.HttpSession s)

configureWhetherToSilentlyAcceptLocalOnlyValues

public MultiSessionAttributeAdapter configureWhetherToSilentlyAcceptLocalOnlyValues(boolean silentlyAcceptLocalOnlyValues)

configureWhetherToSetLocalValuesAlso

public MultiSessionAttributeAdapter configureWhetherToSetLocalValuesAlso(boolean setLocalValuesAlso)

configureWhetherToSetInAll

public MultiSessionAttributeAdapter configureWhetherToSetInAll(boolean setAllKnownSessions)

getAttribute

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

setAttribute

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

removeAttribute

public void removeAttribute(java.lang.String name)

getPreferredSession

public javax.servlet.http.HttpSession getPreferredSession()

getOriginalSession

public javax.servlet.http.HttpSession getOriginalSession()

getId

public java.lang.String getId()

resetExpiration

public MultiSessionAttributeAdapter resetExpiration()