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org.apache.cocoon.components.flow
Class ContinuationsManagerImpl

java.lang.Object
  org.apache.avalon.framework.logger.AbstractLogEnabled
      org.apache.cocoon.components.flow.ContinuationsManagerImpl

All Implemented Interfaces:

Component, Configurable, Contextualizable, LogEnabled, Serviceable, ThreadSafe, ContinuationsManager, Instrumentable

public class ContinuationsManagerImpl
extends AbstractLogEnabled
implements ContinuationsManager, Component, Configurable, ThreadSafe, Instrumentable, Serviceable, Contextualizable

The default implementation of ContinuationsManager.
There are two modes of work:

• standard mode - continuations are stored in single holder. No security is applied to continuation lookup. Anyone can invoke a continuation only knowing the ID. Set "session-bound-continuations" configuration option to false to activate this mode.
• secure mode - each session has it's own continuations holder. A continuation is only valid for the same session it was created for. Session invalidation causes all bound continuations to be invalidated as well. Use this setting for web applications. Set "session-bound-continuations" configuration option to true to activate this mode.

Since:

March 19, 2002

Version:

CVS $Id: ContinuationsManagerImpl.html 1304258 2012-03-23 10:09:27Z ilgrosso $

Author:

Ovidiu Predescu , Michael Melhem

See Also:

ContinuationsManager

Nested Class Summary

protected static class	ContinuationsManagerImpl.ExpirationPredicate
protected static class	ContinuationsManagerImpl.HolderAwareWebContinuation WebContinuation extension that holds also the information about the holder.
protected class	ContinuationsManagerImpl.WebContinuationsHolder A holder for WebContinuations.

Field Summary

protected boolean	bindContinuationsToSession
protected byte[]	bytes
protected Context	context
protected ValueInstrument	continuationsCount
protected int	continuationsCounter
protected CounterInstrument	continuationsCreated
protected ContinuationsManagerImpl.WebContinuationsHolder	continuationsHolder Main continuations holder.
protected CounterInstrument	continuationsInvalidated
protected int	defaultTimeToLive How long does a continuation exist in memory since the last access?
protected SortedSet	expirations Sorted set of WebContinuation instances, based on their expiration time.
protected ValueInstrument	expirationsSize
protected String	instrumentableName
protected boolean	isContinuationSharingBugCompatible
protected SecureRandom	random Random number generator used to create continuation ID
protected ServiceManager	serviceManager

Fields inherited from interface org.apache.cocoon.components.flow.ContinuationsManager

ROLE

Fields inherited from interface org.apache.excalibur.instrument.Instrumentable

EMPTY_INSTRUMENT_ARRAY, EMPTY_INSTRUMENTABLE_ARRAY

Constructor Summary

ContinuationsManagerImpl()

Method Summary

void	configure(Configuration config)
void	contextualize(Context context)
WebContinuation	createWebContinuation(Object kont, WebContinuation parent, int timeToLive, String interpreterId, ContinuationsDisposer disposer) Create a WebContinuation object given a native continuation object and its parent.
void	displayAllContinuations() Dump to Log file all WebContinuations in the system.
protected void	displayExpireSet() Dump to Log file the current contents of the expirations SortedSet
protected void	disposeContinuation(ContinuationsManagerImpl.WebContinuationsHolder continuationsHolder, WebContinuation wk) Makes the continuation inaccessible for lookup, and triggers possible needed cleanup code through the ContinuationsDisposer interface.
protected void	expireContinuations() Remove all continuations which have already expired.
protected WebContinuation	generateContinuation(Object kont, WebContinuation parent, int ttl, String interpreterId, ContinuationsDisposer disposer) Create WebContinuation and generate unique identifier for it.
Instrumentable[]	getChildInstrumentables()
Set	getForest() Get a set of all web continuations.
String	getInstrumentableName()
Instrument[]	getInstruments()
List	getWebContinuationsDataBeanList() Deprecated.
protected void	invalidateContinuations(ContinuationsManagerImpl.WebContinuationsHolder continuationsHolder) Method used by WebContinuationsHolder to notify the continuations manager about session invalidation.
void	invalidateWebContinuation(WebContinuation wk) Invalidates a WebContinuation.
WebContinuation	lookupWebContinuation(String id, String interpreterId) Given a WebContinuation id, retrieve the associated WebContinuation object.
ContinuationsManagerImpl.WebContinuationsHolder	lookupWebContinuationsHolder(boolean createNew) Lookup a proper web continuations holder.
protected void	removeContinuation(ContinuationsManagerImpl.WebContinuationsHolder continuationsHolder, WebContinuation wk) Removes an expired leaf WebContinuation node from its continuation tree, and recursively removes its parent(s) if it they have expired and have no (other) children.
void	service(ServiceManager manager)
void	setInstrumentableName(String instrumentableName)

Methods inherited from class org.apache.avalon.framework.logger.AbstractLogEnabled

enableLogging, getLogger, setupLogger, setupLogger, setupLogger

Methods inherited from class java.lang.Object

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

Field Detail

random

protected SecureRandom random

Random number generator used to create continuation ID

bytes

protected final byte[] bytes

expirations

protected final SortedSet expirations

Sorted set of WebContinuation instances, based on their expiration time. This is used by the background thread to invalidate continuations.

serviceManager

protected ServiceManager serviceManager

context

protected Context context

defaultTimeToLive

protected int defaultTimeToLive

How long does a continuation exist in memory since the last access? The time is in milliseconds, and the default is 1 hour.

isContinuationSharingBugCompatible

protected boolean isContinuationSharingBugCompatible

bindContinuationsToSession

protected boolean bindContinuationsToSession

continuationsHolder

protected ContinuationsManagerImpl.WebContinuationsHolder continuationsHolder

Main continuations holder. Used unless continuations are stored in user session.

instrumentableName

protected String instrumentableName

continuationsCount

protected ValueInstrument continuationsCount

continuationsCounter

protected int continuationsCounter

expirationsSize

protected ValueInstrument expirationsSize

continuationsCreated

protected CounterInstrument continuationsCreated

continuationsInvalidated

protected CounterInstrument continuationsInvalidated

Constructor Detail

ContinuationsManagerImpl

public ContinuationsManagerImpl()
                         throws Exception

Throws:

Exception

Method Detail

contextualize

public void contextualize(Context context)
                   throws ContextException

Specified by:

contextualize in interface Contextualizable

Throws:

ContextException

service

public void service(ServiceManager manager)
             throws ServiceException

Specified by:

service in interface Serviceable

Throws:

ServiceException

configure

public void configure(Configuration config)

Specified by:

configure in interface Configurable

setInstrumentableName

public void setInstrumentableName(String instrumentableName)

Specified by:

setInstrumentableName in interface Instrumentable

getInstrumentableName

public String getInstrumentableName()

Specified by:

getInstrumentableName in interface Instrumentable

getInstruments

public Instrument[] getInstruments()

Specified by:

getInstruments in interface Instrumentable

getChildInstrumentables

public Instrumentable[] getChildInstrumentables()

Specified by:

getChildInstrumentables in interface Instrumentable

createWebContinuation

public WebContinuation createWebContinuation(Object kont,
                                             WebContinuation parent,
                                             int timeToLive,
                                             String interpreterId,
                                             ContinuationsDisposer disposer)

Description copied from interface: ContinuationsManager

Create a WebContinuation object given a native continuation object and its parent. If the parent continuation is null, the WebContinuation returned becomes the root of a tree in the forest.

Specified by:

createWebContinuation in interface ContinuationsManager

Parameters:

kont - an Object value

parent - a WebContinuation value

timeToLive - an int value indicating how long in seconds this continuation will live in the server if not accessed

interpreterId - id of interpreter invoking continuation creation

disposer - a ContinuationsDisposer instance to called when the continuation gets cleaned up.

Returns:

a WebContinuation value

See Also:

WebContinuation

lookupWebContinuation

public WebContinuation lookupWebContinuation(String id,
                                             String interpreterId)

Description copied from interface: ContinuationsManager

Given a WebContinuation id, retrieve the associated WebContinuation object.

Specified by:

lookupWebContinuation in interface ContinuationsManager

Parameters:

id - a String value

interpreterId - Id of an interpreter that queries for the continuation

Returns:

a WebContinuation object, null if no such WebContinuation could be found. Also null if WebContinuation was found but interpreter id does not match the one that the continuation was initially created for.

generateContinuation

protected WebContinuation generateContinuation(Object kont,
                                               WebContinuation parent,
                                               int ttl,
                                               String interpreterId,
                                               ContinuationsDisposer disposer)

Create WebContinuation and generate unique identifier for it. The identifier is generated using a cryptographically strong algorithm to prevent people to generate their own identifiers.

Parameters:

kont - an Object value representing continuation

parent - value representing parent WebContinuation

ttl - WebContinuation time to live

interpreterId - id of interpreter invoking continuation creation

disposer - ContinuationsDisposer instance to use for cleanup of the continuation.

Returns:

the generated WebContinuation with unique identifier

invalidateWebContinuation

public void invalidateWebContinuation(WebContinuation wk)

Description copied from interface: ContinuationsManager

Invalidates a WebContinuation. This effectively means that the continuation object associated with it will no longer be accessible from Web pages. Invalidating a WebContinuation invalidates all the WebContinuations which are children of it.

Specified by:

invalidateWebContinuation in interface ContinuationsManager

Parameters:

wk - a WebContinuation value

disposeContinuation

protected void disposeContinuation(ContinuationsManagerImpl.WebContinuationsHolder continuationsHolder,
                                   WebContinuation wk)

Makes the continuation inaccessible for lookup, and triggers possible needed cleanup code through the ContinuationsDisposer interface.

Parameters:

continuationsHolder -

wk - the continuation to dispose.

removeContinuation

protected void removeContinuation(ContinuationsManagerImpl.WebContinuationsHolder continuationsHolder,
                                  WebContinuation wk)

Removes an expired leaf WebContinuation node from its continuation tree, and recursively removes its parent(s) if it they have expired and have no (other) children.

Parameters:

continuationsHolder -

wk - WebContinuation node

expireContinuations

protected void expireContinuations()

Remove all continuations which have already expired.

invalidateContinuations

protected void invalidateContinuations(ContinuationsManagerImpl.WebContinuationsHolder continuationsHolder)

Method used by WebContinuationsHolder to notify the continuations manager about session invalidation. Invalidates all continuations held by passed continuationsHolder.

lookupWebContinuationsHolder

public ContinuationsManagerImpl.WebContinuationsHolder lookupWebContinuationsHolder(boolean createNew)

Lookup a proper web continuations holder.

Parameters:

createNew - should the manager create a continuations holder in session when none found?

getForest

public Set getForest()

Description copied from interface: ContinuationsManager

Get a set of all web continuations. The set itself will only contain the root continuations. Those will provide access to their children. Since it should not be possible to mess up the actual managed continuations the returned list will contain clones of them. The purpose of this method is clearly monitoring or for debugging the application. It has no direct relationship to functionality of the ContinuationsManager.

Specified by:

getForest in interface ContinuationsManager

getWebContinuationsDataBeanList

public List getWebContinuationsDataBeanList()

Deprecated.

Get a list of all web continuations (data only)

Specified by:

getWebContinuationsDataBeanList in interface ContinuationsManager

displayExpireSet

protected void displayExpireSet()

Dump to Log file the current contents of the expirations SortedSet

displayAllContinuations

public void displayAllContinuations()

Dump to Log file all WebContinuations in the system. This method will be changed to be an internal method solely for debugging purposes just like displayExpireSet().

Specified by:

displayAllContinuations in interface ContinuationsManager