You may want to submit a comment for the JSF specification on changing
this behavior.
On 5/9/07, Wesley Hales <[EMAIL PROTECTED]> wrote:
> So the architect I am working with (Chris Kulinski) came up with the
> following patch to 1.1.5...
>
> Index: src/main/java/javax/faces/component/UIComponent.java
> ===================================================================
> --- src/main/java/javax/faces/component/UIComponent.java
> (revision 536301)
> +++ src/main/java/javax/faces/component/UIComponent.java
> (working copy)
> @@ -59,6 +59,8 @@
>
> public abstract boolean isRendered();
>
> + public abstract boolean isRenderedCached();
> +
> public abstract void setRendered(boolean rendered);
>
> public abstract java.lang.String getRendererType();
> Index: src/main/java/javax/faces/component/UIMessages.java
> ===================================================================
> --- src/main/java/javax/faces/component/UIMessages.java
> (revision 536301)
> +++ src/main/java/javax/faces/component/UIMessages.java
> (working copy)
> @@ -28,7 +28,7 @@
> * @version $Revision$ $Date$
> */
> public class UIMessages
> - extends UIComponentBase
> + extends UIComponentBaseCached
> {
> //------------------ GENERATED CODE BEGIN (do not modify!)
> --------------------
>
> Index: src/main/java/javax/faces/component/UIData.java
> ===================================================================
> --- src/main/java/javax/faces/component/UIData.java
> (revision 536301)
> +++ src/main/java/javax/faces/component/UIData.java
> (working copy)
> @@ -126,7 +126,7 @@
> * @author Manfred Geiler (latest modification by $Author$)
> * @version $Revision$ $Date$
> */
> -public class UIData extends UIComponentBase implements NamingContainer
> +public class UIData extends UIComponentBaseCached implements
> NamingContainer
> {
> private static final int STATE_SIZE = 5;
> private static final int SUPER_STATE_INDEX = 0;
> @@ -577,7 +577,7 @@
> {
> if (context == null)
> throw new NullPointerException("context");
> - if (!isRendered())
> + if (!isRenderedCached())
> return;
> setRowIndex(-1);
> processFacets(context, PROCESS_DECODES);
> @@ -599,7 +599,7 @@
> {
> if (context == null)
> throw new NullPointerException("context");
> - if (!isRendered())
> + if (!isRenderedCached())
> return;
> setRowIndex(-1);
> processFacets(context, PROCESS_VALIDATORS);
> @@ -618,7 +618,7 @@
> {
> if (context == null)
> throw new NullPointerException("context");
> - if (!isRendered())
> + if (!isRenderedCached())
> return;
> setRowIndex(-1);
> processFacets(context, PROCESS_UPDATES);
> @@ -656,7 +656,7 @@
> UIComponent child = (UIComponent) childIter.next();
> if (child instanceof UIColumn)
> {
> - if (!child.isRendered())
> + if (!child.isRenderedCached())
> {
> //Column is not visible
> continue;
> @@ -705,7 +705,7 @@
> UIComponent child = (UIComponent) it.next();
> if (child instanceof UIColumn)
> {
> - if (!child.isRendered())
> + if (!child.isRenderedCached())
> {
> //Column is not visible
> continue;
> Index: src/main/java/javax/faces/component/UIParameter.java
> ===================================================================
> --- src/main/java/javax/faces/component/UIParameter.java
> (revision 536301)
> +++ src/main/java/javax/faces/component/UIParameter.java
> (working copy)
> @@ -28,7 +28,7 @@
> * @version $Revision$ $Date$
> */
> public class UIParameter
> - extends UIComponentBase
> + extends UIComponentBaseCached
> {
> //------------------ GENERATED CODE BEGIN (do not modify!)
> --------------------
>
> Index: src/main/java/javax/faces/component/UIMessage.java
> ===================================================================
> --- src/main/java/javax/faces/component/UIMessage.java
> (revision 536301)
> +++ src/main/java/javax/faces/component/UIMessage.java
> (working copy)
> @@ -30,7 +30,7 @@
> * @version $Revision$ $Date$
> */
> public class UIMessage
> - extends UIComponentBase
> + extends UIComponentBaseCached
> {
> //------------------ GENERATED CODE BEGIN (do not modify!)
> --------------------
>
> Index: src/main/java/javax/faces/component/UIForm.java
> ===================================================================
> --- src/main/java/javax/faces/component/UIForm.java
> (revision 536301)
> +++ src/main/java/javax/faces/component/UIForm.java
> (working copy)
> @@ -28,7 +28,7 @@
> * @version $Revision$ $Date$
> */
> public class UIForm
> - extends UIComponentBase
> + extends UIComponentBaseCached
> implements NamingContainer
> {
> //private static final Log log = LogFactory.getLog(UIForm.class);
> Index: src/main/java/javax/faces/component/UIGraphic.java
> ===================================================================
> --- src/main/java/javax/faces/component/UIGraphic.java
> (revision 536301)
> +++ src/main/java/javax/faces/component/UIGraphic.java
> (working copy)
> @@ -28,7 +28,7 @@
> * @version $Revision$ $Date$
> */
> public class UIGraphic
> - extends UIComponentBase
> + extends UIComponentBaseCached
> {
> private static final String URL_PROPERTY = "url";
> private static final String VALUE_PROPERTY = "value";
> Index: src/main/java/javax/faces/component/UICommand.java
> ===================================================================
> --- src/main/java/javax/faces/component/UICommand.java
> (revision 536301)
> +++ src/main/java/javax/faces/component/UICommand.java
> (working copy)
> @@ -31,7 +31,7 @@
> * @version $Revision$ $Date$
> */
> public class UICommand
> - extends UIComponentBase
> + extends UIComponentBaseCached
> implements ActionSource
> {
> private MethodBinding _action = null;
> Index: src/main/java/javax/faces/component/UIViewRoot.java
> ===================================================================
> --- src/main/java/javax/faces/component/UIViewRoot.java
> (revision 536301)
> +++ src/main/java/javax/faces/component/UIViewRoot.java
> (working copy)
> @@ -38,7 +38,7 @@
> * @version $Revision$ $Date$
> */
> public class UIViewRoot
> - extends UIComponentBase
> + extends UIComponentBaseCached
> {
> public static final String UNIQUE_ID_PREFIX = "_id";
>
> Index: src/main/java/javax/faces/component/UIColumn.java
> ===================================================================
> --- src/main/java/javax/faces/component/UIColumn.java
> (revision 536301)
> +++ src/main/java/javax/faces/component/UIColumn.java
> (working copy)
> @@ -27,7 +27,7 @@
> * @version $Revision$ $Date$
> */
> public class UIColumn
> - extends UIComponentBase
> + extends UIComponentBaseCached
> {
> private static final String FOOTER_FACET_NAME = "footer";
> private static final String HEADER_FACET_NAME = "header";
> Index:
> src/main/java/javax/faces/component/UIComponentBase.java
> ===================================================================
> ---
> src/main/java/javax/faces/component/UIComponentBase.java
> (revision 536301)
> +++
> src/main/java/javax/faces/component/UIComponentBase.java
> (working copy)
> @@ -508,7 +508,7 @@
> throws IOException
> {
> if (context == null) throw new
> NullPointerException("context");
> - if (!isRendered()) return;
> + if (!isRenderedCached()) return;
> Renderer renderer = getRenderer(context);
> if (renderer != null)
> {
> @@ -520,7 +520,7 @@
> throws IOException
> {
> if (context == null) throw new
> NullPointerException("context");
> - if (!isRendered()) return;
> + if (!isRenderedCached()) return;
> Renderer renderer = getRenderer(context);
> if (renderer != null)
> {
> @@ -532,7 +532,7 @@
> throws IOException
> {
> if (context == null) throw new
> NullPointerException("context");
> - if (!isRendered()) return;
> + if (!isRenderedCached()) return;
> Renderer renderer = getRenderer(context);
> if (renderer != null)
> {
> @@ -598,7 +598,7 @@
> public void processDecodes(FacesContext context)
> {
> if (context == null) throw new
> NullPointerException("context");
> - if (!isRendered()) return;
> + if (!isRenderedCached()) return;
> for (Iterator it = getFacetsAndChildren(); it.hasNext(); )
> {
> UIComponent childOrFacet = (UIComponent)it.next();
> @@ -619,7 +619,7 @@
> public void processValidators(FacesContext context)
> {
> if (context == null) throw new
> NullPointerException("context");
> - if (!isRendered()) return;
> + if (!isRenderedCached()) return;
>
> for (Iterator it = getFacetsAndChildren(); it.hasNext(); )
> {
> @@ -640,7 +640,7 @@
> public void processUpdates(FacesContext context)
> {
> if (context == null) throw new
> NullPointerException("context");
> - if (!isRendered()) return;
> + if (!isRenderedCached()) return;
>
> for (Iterator it = getFacetsAndChildren(); it.hasNext(); )
> {
> @@ -1063,6 +1063,7 @@
>
> private Boolean _rendered = null;
> private String _rendererType = null;
> + private Boolean _renderedCached = null;
>
>
>
> @@ -1072,11 +1073,29 @@
> }
>
> public boolean isRendered()
> + {
> + if (_rendered != null) return _rendered.booleanValue();
> + ValueBinding vb = getValueBinding("rendered");
> + // AUTOTRADER: Cache the rendered value so its not computed
> multiple times.
> + _renderedCached = vb != null ?
> (Boolean)vb.getValue(getFacesContext()) : null;
> + return _renderedCached != null ? _renderedCached.booleanValue() :
> DEFAULT_RENDERED;
> + }
> +
> + public boolean isRenderedCached()
> {
> if (_rendered != null) return _rendered.booleanValue();
> +
> + // AUTOTRADER: Cache the rendered value so its not computed
> multiple times.
> + if (_renderedCached != null) {
> + //System.out.println("using CACHED value for:"+getId()+"
> "+this);
> + return _renderedCached.booleanValue();
> + }
> +
> ValueBinding vb = getValueBinding("rendered");
> - Boolean v = vb != null ?
> (Boolean)vb.getValue(getFacesContext()) : null;
> - return v != null ? v.booleanValue() : DEFAULT_RENDERED;
> + // AUTOTRADER: Cache the rendered value so its not computed
> multiple times.
> + _renderedCached = vb != null ?
> (Boolean)vb.getValue(getFacesContext()) : null;
> + //System.out.println("Computing NO CACHE value for:"+getId()+"
> "+this);
> + return _renderedCached != null ? _renderedCached.booleanValue() :
> DEFAULT_RENDERED;
> }
>
> public void setRendererType(String rendererType)
> Index: src/main/java/javax/faces/component/UIPanel.java
> ===================================================================
> --- src/main/java/javax/faces/component/UIPanel.java
> (revision 536301)
> +++ src/main/java/javax/faces/component/UIPanel.java
> (working copy)
> @@ -27,7 +27,7 @@
> * @version $Revision$ $Date$
> */
> public class UIPanel
> - extends UIComponentBase
> + extends UIComponentBaseCached
> {
> //------------------ GENERATED CODE BEGIN (do not modify!)
> --------------------
>
> Index: src/main/java/javax/faces/component/UIOutput.java
> ===================================================================
> --- src/main/java/javax/faces/component/UIOutput.java
> (revision 536301)
> +++ src/main/java/javax/faces/component/UIOutput.java
> (working copy)
> @@ -29,7 +29,7 @@
> * @version $Revision$ $Date$
> */
> public class UIOutput
> - extends UIComponentBase
> + extends UIComponentBaseCached
> implements ValueHolder
> {
> public Object getLocalValue()
>
---------------------------------------------------------------------------------
>
> and here is the UIComponentBaseCached class:
>
> package javax.faces.component;
>
> public abstract class UIComponentBaseCached extends UIComponentBase {
>
> public boolean isRendered()
> {
> return isRenderedCached();
> }
> }
>
>
> So far so good, I will post the results if anything stops working.
>
> Wesley
>
>
>
>
> On 5/9/07, Wesley Hales <[EMAIL PROTECTED]> wrote:
> > I am trying to address this at a framework level (i.e. I'm not rewriting
> the renderer for each component that calls an EL method)
> >
> >
> >
> > On 5/9/07, Adam Winer <[EMAIL PROTECTED]> wrote:
> > > Technically, rendered is supposed to be:
> > > - Constant across
> encodeBegin()/encodeChildren()/encodeEnd()
> > > - Constant across processDecodes()/processValidators()/
> > > processUpdateModel().
> > >
> > > Unfortunately, the latter doesn't help - since a component inside
> > > a table would have processDecodes() called repeatedly,
> > > then processValidators() repeatedly, etc. - and "rendered"
> > > could be different from one row to the next.
> > >
> > > But the former should be fine - if you always fetch and
> > > store the value in encodeBegin() (whether or not encodeBegin()
> > > has previously been called), then use that in encodeChildren()
> > > and encodeEnd(), you should be fine.
> > >
> > > -- Adam
> > >
> > >
> > > On 5/8/07, Simon Kitching < [EMAIL PROTECTED]> wrote:
> > > > Andrew, are you just stating what currently happens or are you saying
> > > > that there is a *reason* for evaluating "rendered" in encodeBegin,
> > > > encodeChildren and encodeEnd?
> > > >
> > > > I can't initially see any reason why it would need to be evaluated
> more
> > > > than once.
> > > >
> > > > UIComponentBase does indeed call isRendered in encodeBegin,
> > > > encodeChildren and encodeEnd. It also implements isRendered as an
> > > > evaluation of the EL expression (myfaces 1.1.3 implementation).
> > > >
> > > > But As Wesley asks, why would it ever make sense for rendered to be
> true
> > > > in encodeBegin, but false in encodeEnd? I cannot see any way that
> would
> > > > be useful, so why not just compute it once then cache it somewhere for
> > > > the rest of that render cycle (eg in a "transient" member of the
> > > > component)? This would be a significant performance boost..
> > > >
> > > > Wesley, your proposed modification which stores the rendered state
> into
> > > > _rendered is not good because setting _rendered will permanently
> > > > override the rendered EL expression, not just for the current render
> > > > cycle but for the lifetime of that component. What is needed is to
> > > > figure out when the first call to isRendered is done *during the
> render
> > > > cycle* and then cache that until rendering finishes. Note that
> > > > isRendered is also called during postback processing, and it's
> perfectly
> > > > reasonable to change this value between postback and render so caching
> > > > really should only be done between encodeBegin() and encodeEnd(). So
> > > > implementing this optimisation is a little tricky - but not impossible
> > > > I'm sure.
> > > >
> > > > Regards,
> > > >
> > > > Simon
> > > >
> > > > Andrew Robinson wrote:
> > > > > At the very least rendered is called during encodeBegin,
> > > > > encodeChildren, and encodeEnd.
> > > > >
> > > > > On 5/8/07, Wesley Hales < [EMAIL PROTECTED]> wrote:
> > > > >> Hello - Why do we continually call isRendered after encodeBegin()?
> > > > >> Once the
> > > > >> begin tag is written out, it shouldn't matter what the body and end
> > > > >> rendered
> > > > >> states are.
> > > > >>
> > > > >> Facelets 1.1.11
> > > > >> Myfaces 1.1.5 & 1.2
> > > > >>
> > > > >> So if I have <t:div rendered="#{ MyBean.alerts > 0}"...
> > > > >> The #{MyBean.alerts method is called 5 times! and it is like this
> for
> > > > >> every
> > > > >> EL eval on the page. I do know that EL can only bind to the
> > > > >> FaceletsContext
> > > > >> and no other scopes... So are there any other options than what I
> have
> > > > >> listed below?
> > > > >>
> > > > >> 1. Tried to modify MyFaces src in UIComponentBase:
> > > > >> public boolean isRendered()
> > > > >> {
> > > > >> if(_rendered == null){
> > > > >>
> > > > >> // our modification! Only compute the rendered value
> once, and
> > > > >> cache for the rest of the lifecycle.
> > > > >> Boolean rend = getExpressionValue("rendered", _rendered,
> > > > >> DEFAULT_RENDERED);
> > > > >> _rendered = rend.booleanValue();
> > > > >> }
> > > > >> return _rendered;
> > > > >> }
> > > > >> This didn't work :( - Something happend to A4J and we had no ideas
> > > > >> what the
> > > > >> implication would be on all components.
> > > > >>
> > > > >> 2. Tried using Facelets <ui:param and <c:set to store the EL in a
> page
> > > > >> scoped variable, then have the variable evaluated in the rendered
> > > > >> attribute.
> > > > >> This didn't work either because it is on FacesContext.
> > > > >>
> > > > >> So this may just be me not fully understanding what JSF does
> behind the
> > > > >> scenes of component rendering, or some people say that the spec is
> > > > >> screwed
> > > > >> up when it comes to this. I'm sure some of the pros can help me out
> > > > >> here :).
> > > > >>
> > > > >> Thx,
> > > > >> Wesley Hales
> > > >
> > > >
> > >
> >
> >
>
>
