org.directwebremoting.dwrp
Class PollHandler

java.lang.Object
  org.directwebremoting.dwrp.PollHandler

All Implemented Interfaces:

Handler

Direct Known Subclasses:

HtmlPollHandler, PlainPollHandler

public class PollHandler
extends java.lang.Object
implements Handler

A Marshaller that output plain Javascript. This marshaller can be tweaked to output Javascript in an HTML context. This class works in concert with CallScriptConduit, they should be considered closely related and it is important to understand what one does while editing the other.

Author:

Joe Walker [joe at getahead dot ltd dot uk]

Field Summary

protected boolean	activeReverseAjaxEnabled Are we doing full reverse ajax
protected boolean	allowGetForSafariButMakeForgeryEasier By default we disable GET, but this hinders old Safaris
static java.lang.String	ATTRIBUTE_CALL_ID How we stash away the results of the request parse
static java.lang.String	ATTRIBUTE_LONGPOLL_SESSION_ID We remember people that are in a long poll so we can kick them out
static java.lang.String	ATTRIBUTE_PAGE How we stash away the results of the request parse
static java.lang.String	ATTRIBUTE_PARAMETERS How we stash away the results of the request parse
static java.lang.String	ATTRIBUTE_PARTIAL_RESPONSE How we stash away the results of the request parse
static java.lang.String	ATTRIBUTE_SESSION_ID How we stash away the results of the request parse
protected ConverterManager	converterManager How we convert parameters
protected int	maxWaitAfterWrite Sometimes with proxies, you need to close the stream all the time to make the flush work.
protected PageNormalizer	pageNormalizer How we turn pages into the canonical form.
protected static int	PARTIAL_RESPONSE_FLUSH The client can only handle partial responses with a 4k data post (can be whitespace) - we're talking IE here.
protected static int	PARTIAL_RESPONSE_NO The client can not handle partial responses
protected static int	PARTIAL_RESPONSE_YES The client can handle partial responses
protected boolean	plain Are we using plain javascript or html wrapped javascript
protected ScriptSessionManager	scriptSessionManager The owner of script sessions
protected ServerLoadMonitor	serverLoadMonitor We need to tell the system that we are waiting so it can load adjust

Constructor Summary

PollHandler(boolean plain)

Method Summary

protected java.lang.String	extractParameter(javax.servlet.http.HttpServletRequest request, java.util.Map parameters, java.lang.String attrName, java.lang.String paramName) Extract a parameter and ensure it is in the request.
void	handle(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) Handle a URL request that has been mapped to this Handler
protected void	notifyThreadsFromSameBrowser(javax.servlet.http.HttpServletRequest request, java.lang.String scriptId) Make other threads from the same browser stop waiting and continue
protected void	sendErrorScript(javax.servlet.http.HttpServletResponse response, java.lang.String script) Send a script to the browser and wrap it in the required prefixes etc.
void	setActiveReverseAjaxEnabled(boolean activeReverseAjaxEnabled) Are we doing full reverse ajax
void	setAllowGetForSafariButMakeForgeryEasier(boolean allowGetForSafariButMakeForgeryEasier)
void	setConverterManager(ConverterManager converterManager) Accessor for the DefaultCreatorManager that we configure
void	setMaxWaitAfterWrite(int maxWaitAfterWrite) Sometimes with proxies, you need to close the stream all the time to make the flush work.
void	setPageNormalizer(PageNormalizer pageNormalizer) Accessor for the PageNormalizer.
void	setPollAndCometEnabled(boolean pollAndCometEnabled) Deprecated. Use setActiveReverseAjaxEnabled(boolean)
void	setScriptSessionManager(ScriptSessionManager scriptSessionManager)
void	setServerLoadMonitor(ServerLoadMonitor serverLoadMonitor) Accessor for the server load monitor
protected boolean	sleepWithContinuation(RealScriptSession scriptSession, Continuation continuation, long preStreamWaitTime) Use a ResumeContinuationScriptConduit to wait
protected boolean	streamWait(javax.servlet.http.HttpServletRequest request, ScriptConduit conduit, RealScriptSession scriptSession, long wait) Perform a wait.

Methods inherited from class java.lang.Object

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

Field Detail

activeReverseAjaxEnabled

protected boolean activeReverseAjaxEnabled

Are we doing full reverse ajax

allowGetForSafariButMakeForgeryEasier

protected boolean allowGetForSafariButMakeForgeryEasier

By default we disable GET, but this hinders old Safaris

maxWaitAfterWrite

protected int maxWaitAfterWrite

Sometimes with proxies, you need to close the stream all the time to make the flush work. A value of -1 indicated that we do not do early closing after writes.

plain

protected boolean plain

Are we using plain javascript or html wrapped javascript

pageNormalizer

protected PageNormalizer pageNormalizer

How we turn pages into the canonical form.

serverLoadMonitor

protected ServerLoadMonitor serverLoadMonitor

We need to tell the system that we are waiting so it can load adjust

converterManager

protected ConverterManager converterManager

How we convert parameters

scriptSessionManager

protected ScriptSessionManager scriptSessionManager

The owner of script sessions

ATTRIBUTE_PARAMETERS

public static final java.lang.String ATTRIBUTE_PARAMETERS

How we stash away the results of the request parse

See Also:

Constant Field Values

ATTRIBUTE_CALL_ID

public static final java.lang.String ATTRIBUTE_CALL_ID

How we stash away the results of the request parse

See Also:

Constant Field Values

ATTRIBUTE_SESSION_ID

public static final java.lang.String ATTRIBUTE_SESSION_ID

How we stash away the results of the request parse

See Also:

Constant Field Values

ATTRIBUTE_PAGE

public static final java.lang.String ATTRIBUTE_PAGE

How we stash away the results of the request parse

See Also:

Constant Field Values

ATTRIBUTE_PARTIAL_RESPONSE

public static final java.lang.String ATTRIBUTE_PARTIAL_RESPONSE

How we stash away the results of the request parse

See Also:

Constant Field Values

ATTRIBUTE_LONGPOLL_SESSION_ID

public static final java.lang.String ATTRIBUTE_LONGPOLL_SESSION_ID

We remember people that are in a long poll so we can kick them out

See Also:

Constant Field Values

PARTIAL_RESPONSE_NO

protected static final int PARTIAL_RESPONSE_NO

The client can not handle partial responses

See Also:

Constant Field Values

PARTIAL_RESPONSE_YES

protected static final int PARTIAL_RESPONSE_YES

The client can handle partial responses

See Also:

Constant Field Values

PARTIAL_RESPONSE_FLUSH

protected static final int PARTIAL_RESPONSE_FLUSH

The client can only handle partial responses with a 4k data post (can be whitespace) - we're talking IE here.

See Also:

Constant Field Values

Constructor Detail

PollHandler

public PollHandler(boolean plain)

Parameters:

plain - Are we using plain javascript or html wrapped javascript

Method Detail

handle

public void handle(javax.servlet.http.HttpServletRequest request,
                   javax.servlet.http.HttpServletResponse response)
            throws java.io.IOException

Description copied from interface: Handler

Handle a URL request that has been mapped to this Handler

Specified by:

handle in interface Handler

Parameters:

request - The HTTP request data

response - Where we write the HTTP response data

Throws:

java.io.IOException - If the write process fails

streamWait

protected boolean streamWait(javax.servlet.http.HttpServletRequest request,
                             ScriptConduit conduit,
                             RealScriptSession scriptSession,
                             long wait)
                      throws java.io.IOException

Perform a wait.

Parameters:

request - The HTTP request, needed to start a Jetty continuation

conduit - A conduit if there is an open stream or null if not

scriptSession - The script that we lock against

wait - How long do we wait for?

Returns:

True if the wait did not end in a shutdown request

Throws:

java.io.IOException - If an IO error occurs

sleepWithContinuation

protected boolean sleepWithContinuation(RealScriptSession scriptSession,
                                        Continuation continuation,
                                        long preStreamWaitTime)

Use a ResumeContinuationScriptConduit to wait

Parameters:

scriptSession - The session that we add the conduit to

continuation - The Jetty continuation object

preStreamWaitTime - The length of time to wait

Returns:

True if the continuation wait worked

notifyThreadsFromSameBrowser

protected void notifyThreadsFromSameBrowser(javax.servlet.http.HttpServletRequest request,
                                            java.lang.String scriptId)

Make other threads from the same browser stop waiting and continue

Parameters:

request - The HTTP request

scriptId - The session id of the current page

extractParameter

protected java.lang.String extractParameter(javax.servlet.http.HttpServletRequest request,
                                            java.util.Map parameters,
                                            java.lang.String attrName,
                                            java.lang.String paramName)

Extract a parameter and ensure it is in the request. This is needed to cope with Jetty continuations that are not real continuations.

Parameters:

request - The HTTP request

parameters - The parameter list parsed out of the request

attrName - The name of the request attribute

paramName - The name of the parameter sent

Returns:

The found value

sendErrorScript

protected void sendErrorScript(javax.servlet.http.HttpServletResponse response,
                               java.lang.String script)
                        throws java.io.IOException

Send a script to the browser and wrap it in the required prefixes etc.

Parameters:

response - The http response to write to

script - The script to write

Throws:

java.io.IOException - if writing fails.

setConverterManager

public void setConverterManager(ConverterManager converterManager)

Accessor for the DefaultCreatorManager that we configure

Parameters:

converterManager - The new DefaultConverterManager

setServerLoadMonitor

public void setServerLoadMonitor(ServerLoadMonitor serverLoadMonitor)

Accessor for the server load monitor

Parameters:

serverLoadMonitor - the new server load monitor

setPageNormalizer

public void setPageNormalizer(PageNormalizer pageNormalizer)

Accessor for the PageNormalizer.

Parameters:

pageNormalizer - The new PageNormalizer

setScriptSessionManager

public void setScriptSessionManager(ScriptSessionManager scriptSessionManager)

Parameters:

scriptSessionManager - the scriptSessionManager to set

setPollAndCometEnabled

public void setPollAndCometEnabled(boolean pollAndCometEnabled)

Deprecated. Use setActiveReverseAjaxEnabled(boolean)

Use setActiveReverseAjaxEnabled(boolean)

Parameters:

pollAndCometEnabled - Are we doing full reverse ajax

setActiveReverseAjaxEnabled

public void setActiveReverseAjaxEnabled(boolean activeReverseAjaxEnabled)

Are we doing full reverse ajax

Parameters:

activeReverseAjaxEnabled - Are we doing full reverse ajax

setAllowGetForSafariButMakeForgeryEasier

public void setAllowGetForSafariButMakeForgeryEasier(boolean allowGetForSafariButMakeForgeryEasier)

Parameters:

allowGetForSafariButMakeForgeryEasier - Do we reduce security to help Safari

setMaxWaitAfterWrite

public void setMaxWaitAfterWrite(int maxWaitAfterWrite)

Sometimes with proxies, you need to close the stream all the time to make the flush work. A value of -1 indicated that we do not do early closing after writes.

Parameters:

maxWaitAfterWrite - the maxWaitAfterWrite to set