This is enabled application-wide with the following parameter:

<context-param>
<param-name>org.icefaces.compressDOM</param-name>
<param-value>true</param-value>
</context-param>

You should see on startup:

INFO: ICEfaces init parameter org.icefaces.compressDOM set to true

It would be possible to allow this to be configurable per-view. The question is whether that would be useful.

compressDOM verified working on Google App Engine.

Nullpointer Exception is seen when user tries to interact with the compat component-showcase on Tomcat6 server. Please see attached screenshot.

Jun 2, 2010 10:47:10 AM org.icefaces.context.DOMResponseWriter getOldDocument
SEVERE: Failed to restore old DOM
org.jvnet.fastinfoset.FastInfosetException: org.w3c.dom.DOMException: NAMESPACE_ERR: An attempt is made to create or change an object in a way which is incorrect with regard to namespaces. atcom.sun.xml.fastinfoset.dom.DOMDocumentParser.parse(DOMDocumentParser.java:121)

Caused by: org.w3c.dom.DOMException: NAMESPACE_ERR: An attempt is made to create or change an object in a way which is incorrect with regard to namespaces.
at com.sun.org.apache.xerces.internal.dom.AttrNSImpl.setName(AttrNSImpl.java:105)

SEVERE: Error Rendering View[/showcase.xhtml]
java.lang.NullPointerException
at org.icefaces.util.DOMUtils.compareNodes(DOMUtils.java:337)

compat auctionMonitor although the scripts work following exception is seen on the server several time:

SEVERE: Servlet.service() for servlet Faces Servlet threw exception
java.lang.NullPointerException
at java.io.Writer.write(Writer.java:140)
at com.sun.faces.context.AjaxExceptionHandlerImpl.handlePartialResponseError(AjaxExceptionHandlerImpl.java:200)

Cannot load auction application on Tomcat6 server, Following seen on the browser:

exception

javax.servlet.ServletException: com/sun/xml/fastinfoset/dom/DOMDocumentSerializer
javax.faces.webapp.FacesServlet.service(FacesServlet.java:325)

root cause

java.lang.NoClassDefFoundError: com/sun/xml/fastinfoset/dom/DOMDocumentSerializer
org.icefaces.context.DOMResponseWriter.saveOldDocument(DOMResponseWriter.java:563)
org.icefaces.context.DOMResponseWriter.endDocument(DOMResponseWriter.java:247)
com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:388)
com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:126)
com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:127)
com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139)
javax.faces.webapp.FacesServlet.service(FacesServlet.java:313)

When compressDOM is tested, FastInfoset.jar needs to be included in WEB-INF/lib. Please retest auction with the .jar file added.

The org.w3c.dom.DOMException: NAMESPACE_ERR is caused by the presences of namespaces in the DOM. I will investigate whether the FastInfoset Parser/Serializer can be configured to be namespace-aware. If not, it will be necessary to remove namespaces from the source document or implement a pre-processor that strips namespaces from the DOM before applying compression.

Enabling namespaceAware on the DocumentBuilder does not seem to be working, but the following setting appears to work:

doc.setStrictErrorChecking(false);

FastInfoset is already using namespaceAware APIs, the difficulty arises from the very strict behavior of Document.createAttributeNS():

NAMESPACE_ERR: Raised if the qualifiedName is a malformed qualified name, if the qualifiedName has a prefix and the namespaceURI is null, if the qualifiedName has a prefix that is "xml" and the namespaceURI is different from " http://www.w3.org/XML/1998/namespace", if the qualifiedName or its prefix is "xmlns" and the namespaceURI is different from "http://www.w3.org/2000/xmlns/", or if the namespaceURI is "http://www.w3.org/2000/xmlns/" and neither the qualifiedName nor its prefix is "xmlns".

It could be argued that not passing "http://www.w3.org/2000/xmlns/" for the namespaceURI for "xmlns" is a bug in the FastInfoset implementation, but this is not the only case where namespaces might be used without following the rules strictly. The solution is to disable error checking during FastInfoset compression (which will also improve performance). If strict DOM correctness is desired, this can be added as a later feature that specifically enables error checking.

Server:Tomcat6
Browser: FF3.6

Compat Component-showcase: scripts ran successfully but following error was seen on the server console:

SEVERE: Error Rendering View[/showcase.xhtml]
java.lang.NullPointerException
at org.icefaces.event.WindowAndViewIDSetup$1.encode(WindowAndViewIDSetup.java:52)
at org.icefaces.event.UIOutputWriter.encodeBegin(UIOutputWriter.java:32)

Compat AuctionMonitor: test scripts ran successfully but following error seen on the server console:

SEVERE: Error Rendering View[/auctionMonitor.xhtml]
java.lang.NullPointerException
at org.icefaces.event.WindowAndViewIDSetup$1.encode(WindowAndViewIDSetup.java:52)

java.lang.NullPointerException
at org.icefaces.event.WindowAndViewIDSetup$1.encode(WindowAndViewIDSetup.java:52)
at org.icefaces.event.UIOutputWriter.encodeBegin(UIOutputWriter.java:32)

Auction: still cannot load the application, Still seeing error on the browser:
java.lang.NoClassDefFoundError: com/sun/xml/fastinfoset/dom/DOMDocumentSerializer

auction appears to be missing FastInfoset.jar, so please ensure that the .jar is present in auction.war.

The NullPointerException will require further investigation.

Glimmer revison# 21717
Server: Tomcat6
Browser: FF3.6

Tested by manually placing FastInfoset.jar in lib folder.
Auction: all pass
Basic: all pass
ElementUpdate: all pass
Fajax: all pass
Scopes: Window Scope test failes. counter is reset when user revisited the page. Rest pass.

QA confirms that the Window Scope test issue is not related to the compressDOM setting. Fixed!