Af:commandImageLink property expressions evaluated more than once

Question

hi
An image link like this ...
<af:commandImageLink text="commandImageLink 1" id="cil1"
                     rendered="#{r_tryCommandImageLink.myCImageLinkRendered}"/>... that gets its rendered property value from a managed-bean method like this ...
public class TryCommandImageLink
     protected int fIsMyCImageLinkRenderedCallCount = 0;
     public boolean isMyCImageLinkRendered()
          System.out.println("TryCommandImageLink.isMyCImageLinkRendered() : begin"
               + " : count = " + (++fIsMyCImageLinkRenderedCallCount));
          return true;
}... results in output like this ...
TryCommandImageLink.isMyCImageLinkRendered() : begin : count = 1
TryCommandImageLink.isMyCImageLinkRendered() : begin : count = 2
TryCommandImageLink.isMyCImageLinkRendered() : begin : count = 3
TryCommandImageLink.isMyCImageLinkRendered() : begin : count = 4
TryCommandImageLink.isMyCImageLinkRendered() : begin : count = 5So, the managed-bean method is called 5 times.
See also this example application created using JDeveloper 11.1.1.5.0,
at http://www.consideringred.com/files/oracle/2011/EvaluatedMoreThanOnceApp-v0.01.zip
question
- (q1) Why is the EL expression for the rendered property of a af:commandImageLink evaluated 5 times?
(A similar issue (Re: af:commandButton text EL expression evaluated twice) in forum thread "af:commandButton text EL expression evaluated twice" seems to be resolved (e.g. in tryCommandButton.jspx in EvaluatedMoreThanOnceApp-v0.01.zip).)
many thanks
Jan Vervecken

Answer 1

Thanks for your reply John.
John Stegeman wrote:
... 1). Do you know during which phases it's being called (you could put a phase listener that just logs so that you can see)Please consider the modified example application
at http://www.consideringred.com/files/oracle/2012/EvaluatedMoreThanOnceApp-v0.02.zip
It shows that the isMyCImageLinkRendered() method is called during the jsfRenderResponse phase:
MyLogPagePhaseListener.beforePhase() : ( 9) jsfRestoreView : /faces : /tryCommandImageLink
MyLogPagePhaseListener.afterPhase()  : ( 9) jsfRestoreView
MyLogPagePhaseListener.beforePhase() : ( 9) jsfRestoreView : /faces : /tryCommandImageLink
MyLogPagePhaseListener.afterPhase()  : ( 9) jsfRestoreView
MyLogPagePhaseListener.beforePhase() : ( 0) initContext : /faces : /tryCommandImageLink
MyLogPagePhaseListener.afterPhase()  : ( 0) initContext
MyLogPagePhaseListener.beforePhase() : ( 1) prepareModel : /faces : /tryCommandImageLink
MyLogPagePhaseListener.afterPhase()  : ( 1) prepareModel
MyLogPagePhaseListener.beforePhase() : (14) jsfRenderResponse : /faces : /tryCommandImageLink
MyLogPagePhaseListener.beforePhase() : ( 8) prepareRender : /faces : /tryCommandImageLink
MyLogPagePhaseListener.afterPhase()  : ( 8) prepareRender
TryCommandImageLink.isMyCImageLinkRendered() : begin : count = 1
TryCommandImageLink.isMyCImageLinkRendered() : begin : count = 2
TryCommandImageLink.isMyCImageLinkRendered() : begin : count = 3
TryCommandImageLink.isMyCImageLinkRendered() : begin : count = 4
TryCommandImageLink.isMyCImageLinkRendered() : begin : count = 5
MyLogPagePhaseListener.afterPhase()  : (14) jsfRenderResponseIf the link is clicked, it also seems to be called during the phases jsfApplyRequestValues, jsfProcessValidations and jsfUpdateModelValues, resulting 8 calls:
MyLogPagePhaseListener.beforePhase() : ( 0) initContext : /faces : /tryCommandImageLink
MyLogPagePhaseListener.afterPhase()  : ( 0) initContext
MyLogPagePhaseListener.beforePhase() : ( 1) prepareModel : /faces : /tryCommandImageLink
MyLogPagePhaseListener.afterPhase()  : ( 1) prepareModel
MyLogPagePhaseListener.beforePhase() : (10) jsfApplyRequestValues : /faces : /tryCommandImageLink
TryCommandImageLink.isMyCImageLinkRendered() : begin : count = 1
MyLogPagePhaseListener.afterPhase()  : (10) jsfApplyRequestValues
MyLogPagePhaseListener.beforePhase() : (11) jsfProcessValidations : /faces : /tryCommandImageLink
TryCommandImageLink.isMyCImageLinkRendered() : begin : count = 2
MyLogPagePhaseListener.afterPhase()  : (11) jsfProcessValidations
MyLogPagePhaseListener.beforePhase() : (12) jsfUpdateModelValues : /faces : /tryCommandImageLink
TryCommandImageLink.isMyCImageLinkRendered() : begin : count = 3
MyLogPagePhaseListener.afterPhase()  : (12) jsfUpdateModelValues
MyLogPagePhaseListener.beforePhase() : ( 5) validateModelUpdates : /faces : /tryCommandImageLink
MyLogPagePhaseListener.afterPhase()  : ( 5) validateModelUpdates
MyLogPagePhaseListener.beforePhase() : (13) jsfInvokeApplication : /faces : /tryCommandImageLink
MyLogPagePhaseListener.afterPhase()  : (13) jsfInvokeApplication
MyLogPagePhaseListener.beforePhase() : ( 7) metadataCommit : /faces : /tryCommandImageLink
MyLogPagePhaseListener.afterPhase()  : ( 7) metadataCommit
MyLogPagePhaseListener.beforePhase() : (14) jsfRenderResponse : /faces : /tryCommandImageLink
MyLogPagePhaseListener.beforePhase() : ( 8) prepareRender : /faces : /tryCommandImageLink
MyLogPagePhaseListener.afterPhase()  : ( 8) prepareRender
TryCommandImageLink.isMyCImageLinkRendered() : begin : count = 4
TryCommandImageLink.isMyCImageLinkRendered() : begin : count = 5
TryCommandImageLink.isMyCImageLinkRendered() : begin : count = 6
TryCommandImageLink.isMyCImageLinkRendered() : begin : count = 7
TryCommandImageLink.isMyCImageLinkRendered() : begin : count = 8
MyLogPagePhaseListener.afterPhase()  : (14) jsfRenderResponse
John Stegeman wrote:... 2). Does the same behaviour occur with the visible property?In a similar way I tried:
<af:commandImageLink text="commandImageLink to try visible" id="cil1"
                     visible="#{r_tryCImageLinkVisible.myCImageLinkVisible}"/>This results in 2 calls during the jsfRenderResponse phase:
MyLogPagePhaseListener.beforePhase() : ( 9) jsfRestoreView : /faces : /tryCImageLinkVisible
MyLogPagePhaseListener.afterPhase()  : ( 9) jsfRestoreView
MyLogPagePhaseListener.beforePhase() : ( 9) jsfRestoreView : /faces : /tryCImageLinkVisible
MyLogPagePhaseListener.afterPhase()  : ( 9) jsfRestoreView
MyLogPagePhaseListener.beforePhase() : ( 0) initContext : /faces : /tryCImageLinkVisible
MyLogPagePhaseListener.afterPhase()  : ( 0) initContext
MyLogPagePhaseListener.beforePhase() : ( 1) prepareModel : /faces : /tryCImageLinkVisible
MyLogPagePhaseListener.afterPhase()  : ( 1) prepareModel
MyLogPagePhaseListener.beforePhase() : (14) jsfRenderResponse : /faces : /tryCImageLinkVisible
MyLogPagePhaseListener.beforePhase() : ( 8) prepareRender : /faces : /tryCImageLinkVisible
MyLogPagePhaseListener.afterPhase()  : ( 8) prepareRender
TryCImageLinkVisible.isMyCImageLinkVisible() : begin : count = 1
TryCImageLinkVisible.isMyCImageLinkVisible() : begin : count = 2
MyLogPagePhaseListener.afterPhase()  : (14) jsfRenderResponseIf the link is clicked, still 2 calls during the jsfRenderResponse phase:
MyLogPagePhaseListener.beforePhase() : ( 0) initContext : /faces : /tryCImageLinkVisible
MyLogPagePhaseListener.afterPhase()  : ( 0) initContext
MyLogPagePhaseListener.beforePhase() : ( 1) prepareModel : /faces : /tryCImageLinkVisible
MyLogPagePhaseListener.afterPhase()  : ( 1) prepareModel
MyLogPagePhaseListener.beforePhase() : (10) jsfApplyRequestValues : /faces : /tryCImageLinkVisible
MyLogPagePhaseListener.afterPhase()  : (10) jsfApplyRequestValues
MyLogPagePhaseListener.beforePhase() : (11) jsfProcessValidations : /faces : /tryCImageLinkVisible
MyLogPagePhaseListener.afterPhase()  : (11) jsfProcessValidations
MyLogPagePhaseListener.beforePhase() : (12) jsfUpdateModelValues : /faces : /tryCImageLinkVisible
MyLogPagePhaseListener.afterPhase()  : (12) jsfUpdateModelValues
MyLogPagePhaseListener.beforePhase() : ( 5) validateModelUpdates : /faces : /tryCImageLinkVisible
MyLogPagePhaseListener.afterPhase()  : ( 5) validateModelUpdates
MyLogPagePhaseListener.beforePhase() : (13) jsfInvokeApplication : /faces : /tryCImageLinkVisible
MyLogPagePhaseListener.afterPhase()  : (13) jsfInvokeApplication
MyLogPagePhaseListener.beforePhase() : ( 7) metadataCommit : /faces : /tryCImageLinkVisible
MyLogPagePhaseListener.afterPhase()  : ( 7) metadataCommit
MyLogPagePhaseListener.beforePhase() : (14) jsfRenderResponse : /faces : /tryCImageLinkVisible
MyLogPagePhaseListener.beforePhase() : ( 8) prepareRender : /faces : /tryCImageLinkVisible
MyLogPagePhaseListener.afterPhase()  : ( 8) prepareRender
TryCImageLinkVisible.isMyCImageLinkVisible() : begin : count = 1
TryCImageLinkVisible.isMyCImageLinkVisible() : begin : count = 2
MyLogPagePhaseListener.afterPhase()  : (14) jsfRenderResponseQuestion (q1) remains.
regards
Jan