Tip : resolve JSF expressions at runtime

hi
Sometimes it might be useful to be able to take a look into your application at runtime.
One way to do this, is to pass JSF expressions into your application and see how they get resolved.
The simple ExpressionResolver bean and expressionResolver.jspx page below enable you to do this.
(*) the ExpressionResolver class :
package view.util;
import javax.faces.application.Application;
import javax.faces.context.FacesContext;
import javax.faces.el.ValueBinding;
public class ExpressionResolver
     private String fExpression = null;
     private Object fExpressionResult = null;
     public String resolveButton_action()
          FacesContext vFacesContext = FacesContext.getCurrentInstance();
          Application vApplication = vFacesContext.getApplication();
          try
               ValueBinding vExpressionVB =
                    vApplication.createValueBinding(getExpression());
               setExpressionResult("unable to resolve expression : "
                    + getExpression());
               if (vExpressionVB != null)
                    setExpressionResult(vExpressionVB.getValue(vFacesContext));
          catch (Exception ex)
               setExpressionResult("error resolving expression : ex = " + ex);
          return null;
     public void setExpression(String expression)
          this.fExpression = expression;
     public String getExpression()
          return fExpression;
     public void setExpressionResult(Object expressionResult)
          this.fExpressionResult = expressionResult;
     public Object getExpressionResult()
          return fExpressionResult;
}(*) the expressionResolver.jspx page :
<?xml version='1.0' encoding='windows-1252'?>
<jsp:root xmlns:jsp="http://java.sun.com/JSP/Page" version="2.0"
          xmlns:h="http://java.sun.com/jsf/html"
          xmlns:f="http://java.sun.com/jsf/core">
<jsp:output omit-xml-declaration="true" doctype-root-element="HTML"
              doctype-system="http://www.w3.org/TR/html4/loose.dtd"
              doctype-public="-//W3C//DTD HTML 4.01 Transitional//EN"/>
<jsp:directive.page contentType="text/html;charset=windows-1252"/>
<f:view>
    <html>
      <head>
        <meta http-equiv="Content-Type" content="text/html; charset=windows-1252"/>
        <title>expressionResolver</title>
      </head>
      <body><h:form>
          <h:panelGrid columns="1">
            <h:outputText value="expression resolver"/>
            <h:panelGrid columns="2" rendered="true">
              <h:inputTextarea id="expression"
                               value="#{expressionResolver.expression}"
                               rows="4" cols="50"/>
              <h:commandButton value="resolve" id="resolveButton"
                               action="#{expressionResolver.resolveButton_action}"/>
            </h:panelGrid>
            <h:outputText value="#{expressionResolver.expressionResult}"/>
          </h:panelGrid>
        </h:form></body>
    </html>
</f:view>
</jsp:root>(*) the configuration in faces-config.xml :
<managed-bean>
    <managed-bean-name>expressionResolver</managed-bean-name>
    <managed-bean-class>view.util.ExpressionResolver</managed-bean-class>
    <managed-bean-scope>request</managed-bean-scope>
</managed-bean>So if you add these to an application, for example the "Oracle ADF SRDemo Application", you could resolve expressions like these at runtime (or any other expression you can come up with):
#{data.SRPublicFacade.methodResults}
#{data.SRPublicFacade.methodResults.SRPublicFacade_dataProvider_findServiceRequests_result}
#{data.SRPublicFacade.methodResults.SRPublicFacade_dataProvider_findServiceRequests_result[0].problemDescription}
#{resources['srdemo.version']}
#{userInfo.userName}
#{userState.searchFirstTime}All suggestions for improvement are welcome of course.
One more thing ... a page like this should probably not be part of a production deployment of your application or it should be properly secured.
regards
Jan Vervecken

Jan,
this looks useful to me, especially if you work in support. Do you have a blog where this tip is mentioned, so we can link to it ?
Frank

Similar Messages

How to use Type Casting in JSF Expression Language

I have an attribute CategoryId in my VO of type oracle.jbo.domain.Number. I am trying to use the expression of Boolean item in JSF as #{row.CategoryId != 4}
Here is the JSF code:
                      <af:column id="s141NewItem3Col" noWrap="true" width="100"
                                 rowHeader="false">
                        <f:facet name="header">
                          <af:outputLabel value="CAtIDDeq4" showRequired="false"
                                          id="ol18"/>
                        </f:facet>
                        <af:inputText id="s141NewItem3"
                                      value="#{row.CategoryId != 4}"
                                      label="CAtIDDeq4" required="false"
                                      readOnly="#{((pageFlowScope.ContractRightCategoriesTable.newRow) and (!(jhsUserRoles['RM, ADMIN, AllButTitl, AllButAdmn']))) or ((!pageFlowScope.ContractRightCategoriesTable.newRow) and (!(jhsUserRoles['RM, ADMIN, AllButTitl, AllButAdmn'])))}"></af:inputText>
                      </af:column>I am getting the run time exception as "Can not convert 4 of type class oracle.jbo.domain.Number to class java.lang.Long".
I am wondering how the row.CategoryId is treated as Long?. PLease advise. Also, will I be able to use type casting expressions in JSF Expression Language?
Thanks, Pradeep

use attributeValue
Try *#{row.bindings.CategoryId.attributeValue != 4}* ?
Check this thread for details which discusses about the same:
El expression to disable or enable
Thanks,
Navaneeth

MultiRowEdt-JBO-35000: Cant resolve spel expression for attribute {0}in{1}

Hi All,
i'm in the process of completing the mutli row edit tutorial that I downloaded from this site. I'm using 10.1.2, adf bc and jsp's.
I've competed the tutorial and am getting an error JBO-35000: Cant resolve spel expression for attribute {0} in {1} .
I've checked that my attribute names are the same as the VO and have created a BeanInfo class to handle the mapping of these attributes. All appears as it should, so not sure where to go from here.
Any ideas would be gratefully received.
Thanks in advance,
Newbw

hello,
I'm facing the same problem in implementing mutli row edit tutorial.
I'm using JDeveloper 9051.
Can u please tell me how did u solve ur problem as i didnt understand what u've posted on forum "spelt my VO wrong".
Please reply. waiting
Thanks in advance
Mina

Is it possible to access a consant attribute with a JSF expression?

I have a class with constant attributes like this:
public static final int CONSTANT_VALUE = 111;
How do I access them with a JSF expression?
#{myBean.CONSTANT_VALUE} does not work.
Do I have to write getters for them? I heared somewhere that its not bossible
to access them directly.
Thanks!

just write a get method of this attribute

Resolving data-reference at runtime ( cl_abap_typedescr)

Hi all,
At runtime, I need to find out if a data-reference of created data
refers to a data-element or not.
In will give you an example of what I mean:
data: dummy         TYPE bukrs,
      descr_ref     TYPE REF TO cl_abap_typedescr,
      descr_datael TYPE REF TO cl_abap_elemdescr,
      p_datael      type string value ''.
descr_ref = cl_abap_typedescr=>describe_by_data( dummy ).
MOVE descr_ref ?TO descr_datael.
p_datael = descr_datael->help_id. "p_datael has now value BUKRS
How is this done, if we work with a datareferences?
I'm pretty sure it should be feasible - but I'm stuck here...
Task: same as above - find out data-element of dummy.
data: dummy         TYPE ref to data,
      descr_ref     TYPE REF TO cl_abap_typedescr,
      descr_datael TYPE REF TO cl_abap_elemdescr,
      p_datael      type string value ''.
create dummy type bukrs.
descr_ref = cl_abap_typedescr=>describe_by_data( dummy ).
"descr_ref->type_kind this time indicates, that we work with referenced data.
"How to progress from here on?
Thanks in advance. Points will be granted if issue can be solved!

Hello Edwin
The sample report ZUS_SDN_RTTI_DATA_ELEMENT shows how to address your question.
*& Report ZUS_SDN_RTTI_DATA_ELEMENT
*& Thread: resolving data-reference at runtime ( cl_abap_typedescr)
*& <a class="jive_macro jive_macro_thread" href="" __jive_macro_name="thread" modifiedtitle="true" __default_attr="770681"></a>
REPORT zus_sdn_rtti_data_element.
DATA: gdo_dummy         TYPE REF TO data,
      go_typedescr      TYPE REF TO cl_abap_typedescr,
      go_elemdescr      TYPE REF TO cl_abap_elemdescr,
      p_datael      TYPE string VALUE ''.
PARAMETERS:
p_rolln   TYPE rollname DEFAULT 'BUKRS'.
START-OF-SELECTION.
CREATE DATA gdo_dummy TYPE (p_rolln).
go_typedescr = cl_abap_typedescr=>describe_by_data_ref( gdo_dummy ).
go_elemdescr ?= go_typedescr.
IF ( go_elemdescr->kind = cl_abap_elemdescr=>kind_elem AND
       go_elemdescr->help_id = 'BUKRS' ).
    MESSAGE 'Is of TYPE BUKRS' TYPE 'S'.
ELSE.
    MESSAGE 'Is not of TYPE BUKRS' TYPE 'S'.
ENDIF.
END-OF-SELECTION.
Regards
Uwe

Concatenation in JSF expressions (EL)

Hi, does anyone know if something like is possible ? (problem is that I would like different texts for different rows in a datatable using a message bundle)
<h:outputText value="'page1' + msg[somevariable] + 'extra text'"></h:outputText>
Appreciate some help.
Thanks

You can't concat values in [ ].
I use a bean do do the concatenation :
<h:outputText value="#{lang[concat['mpr.canton.,#offer.canton']]}"/>
Source :
public class ConcatenationBean extends HashMap
    // log4j static Logger for this class
    private static final Logger logger = Logger.getLogger(ConcatenationBean.class);
    public ConcatenationBean()
        super();
     * Concat the string separated by a comma Evaluate JSF EL expression if
     * token begin by # or $
     * @param inObject :
     *            is the list of string to concat separated by a comma. return a
     *            String exemple : <h:outputText
     *            value="#{lang[concat['mpr.canton.,#offer.canton']]}"/>
    public Object get(Object inObject)
        StringBuffer resultBuffer = new StringBuffer();
        try
            String inToken = (String) inObject;
            StringTokenizer tok = new StringTokenizer((String) inToken, ",", false);
            while (tok.hasMoreTokens())
                String token = tok.nextToken().trim();
                if (logger.isDebugEnabled())
                    logger.debug("inToken=" + token);
                if (token.startsWith("#{"))
                    Object tokenEvaluated = FacesHelper.getElValue(token);
//                    if (tokenEvaluated instanceof String)
                        resultBuffer.append(String.valueOf(tokenEvaluated));
//                    else
//                        logger.error("#{...} EL expression is not a String : " + token);
                else if (token.startsWith("${"))
                    token = token.substring(2, token.length() - 1);
                    if (logger.isDebugEnabled())
                        logger.debug("token $ =" + token);
                    Object tokenEvaluated = FacesHelper.getElValue(FacesHelper.getJsfEl(token));
//                    if (tokenEvaluated instanceof String)
                        resultBuffer.append(String.valueOf(tokenEvaluated));
//                    else
//                        logger.error("${...} EL expression is not a String : " + token);
                else if (token.startsWith("#"))
                    token = token.substring(1);
                    Object tokenEvaluated = FacesHelper.getElValue(FacesHelper.getJsfEl(token));
//                    if (tokenEvaluated instanceof String)
                        resultBuffer.append(String.valueOf(tokenEvaluated));
//                    else
//                        logger.error("#... expression is not a String : " + token);
                else
                    resultBuffer.append(token);
        catch (Throwable e)
            logger.error(null, e);
        return resultBuffer.toString();
}I hope it will help you...

f:validator tag validatorId attribute doesn't resolve EL Expressions?

I have a set of custom validators that I've written to validate certain data types used in our application. I have tested all of them and verified that they all work. Now I want to display a data table showing a list of data input fields, each bound to an object of a different type. During the iteration the 'item' has a method called "getValidatorIdentifier()" which returns a String that is the ID of the validator registered in my faces_config.xml file. Using the following code, I want to set the validatorId dynamically for each inputText field in my data table.
<h:dataTable var="item" ..... >
<h:inputText id="itemValue"
required="#{item.required}"
value="#{item.relatedAsset.asset}">
<f:validator validatorId="#{item.validatorIdentifier}" /> 
</h:inputText>
</h:dataTable>
Now, when I hard-code the validatorId attribute to the registered validator ID, it works fine. When I try to use the EL expression, as in the above code, I get the following when I access the page:
java.lang.NullPointerException: Argument Error: One or more parameters are null.
     com.sun.faces.application.ApplicationImpl.createValidator(ApplicationImpl.java:712)
     javax.faces.webapp.ValidatorTag.createValidator(ValidatorTag.java:146)
     javax.faces.webapp.ValidatorTag.doStartTag(ValidatorTag.java:109)
I looked in the O'Reilly JavaServer Faces book and it states that the validatorId attribute should accept an EL expression type of 'any', so I am assuming that the expression #{item.validatorIdentifier} should work.
Am I making a mistake here, or is there a bug I don't know about in the f:validator tag?
Thanks for your help.

A little more information on this issue.
When I attempt to resolve the validatorId from the 'item' var (the variable in the data table iteration) I get the problem described in my first posting. Now if I create an outputText element simply to echo the value of item.validatorIdentifier, it displays the correct value that I would expect.
<f:validator validatorId="#{item.validatorIdentifier}" /> 
<h:outputText value="#{item.validatorIdentifier}"/> 
Now, just to see if it was the EL, I modified the validator tag to use an EL expression bound to a getValidatorId() method in a managed bean class. In other words, when I'm NOT trying to resolve the validatorId from the iteration variable, an EL expression works.
<f:validator validatorId="#{myManagedBean.validatorId}" /> 
But, this is not a solution, since each element in my dataTable iteration needs to report to me what its validator ID should be.

Upgraded to APEX 3.0 in Oracle 10g Express, broken runtime

Hi,
I'm a newbie trying to use APEX with Oracle 10g Express on my laptop. I ran the upgrade to the latest APEX version (3.x). It seems to have worked for design-time, but the run-time has broken. I gave up trying to import samle apps, and built a simple one-page application from scratch, and got the below error after entering username/password and clicking the login button:
ERR-1777: Page 101 provided no page to branch to. Please report this error to your application administrator.
Thanks in advacne,
Shahram

No longer a problem, I needed to successfully log on to the admin account and associate the developer user to a schema other than SYSTEM, I'm not sure why SYSTEM ended up being the default schema for the workspace during the upgrdae.
Shahram

Include jsp/jsf code in a jsf page at runtime

Hello,
I have a problem. I must get data from a Firebird db. The data is posted in jsp/jsf
code. I've tried to get them through a servlet. The problem is that when I include
result in my jsf page, the code doesn't get compiled.
If I include code with a <h:outputText> or a jsp action <jsp:include> or a <c:import
url> the code doesn't get compiled. If I include code with directive <%include> it is
translated correctly, but include directive accepts only physical files.
Any suggestion?
Thanks

Hello,
I have a problem. I must get data from a Firebird db. The data is posted in jsp/jsf
code. I've tried to get them through a servlet. The problem is that when I include
result in my jsf page, the code doesn't get compiled.
If I include code with a <h:outputText> or a jsp action <jsp:include> or a <c:import
url> the code doesn't get compiled. If I include code with directive <%include> it is
translated correctly, but include directive accepts only physical files.
Any suggestion?
Thanks

How do I concatenate strings in JSF expressions (EL)?

So I want to do something like:
<h:outputText id="foo" value="msgs['label.' + prop]" />
"prop" is a variable involved in a loop using a dataTable. It'll have a string value like "firstName" or something. 'msgs' refers to a resource bundle initialized earlier in the JSP.
The above line doesn't work because in JSF, the plus(+) symbol is only for arithmetic and so, exceptions get thrown.
How do I do the equivalent of the above? I can rename my resource bundles to not have the 'label.' prefix, but there's got to be a better way.
Any help one can give would be great. Thanks!
Jimmy Ho

I'm not sure I understand. I have no database interactions. The things I'm trying to concatenate to ".label" is just some list of strings I get from a properties files somewhere in my code.
Ahaaaa, not what I understood...somehow :) sorry
I can see how I can change each String to some Foobar object where I can do blah.label and blah.value, and make that work, but creating a whole new class seems excessive. Is there another way?
I dont know if there is straight forward one, just like + with strings, another idea is to open the properties file and read the strings you need and append to the .label...if that makes any reasonable sense

JSF page shows runtime error when application deployed in local oc4j server

I developed a wsrp portlet producer based application and delployed it in oc4j application server. But when I open input.jsp page url which has JackBe portlet mashlets on it in web browser.
I get an error 'mdsId=/oracle/adf/portlet/wsrpPortletProducer1_1223631729156/ap/E1default_e62a8fe5_011e_1000_8002_ac144d7e5e23.pxml not found'.
Oc4j, oracle database instance and JackBe presto are running on same local machine.
I am using trial version of JackBe presto. Similarly while installing oc4jpdk, I do need to change ORACLE_HOME path to oc4j from oracle database folder which stops running of my oracle database(Oracle10g) instance on my machine. Please suggest me with possible solution pointers to resolve it.

Hi
Thanks for the input. I checked at the forum you referred to. I did not find any similar question discussed on the forum. I highly appreciate if you suggest me few exact pointers to this issue. I am losing on time and appreciate quick response.
Thanks & Regards
Abhijit Kulkarni

JSF expression language question

Hi, is it possible to write something like this:
<h:dataTable value="#{myControllerBean.persons}" var="person">
<h:column>
<h:outputText value="#{person.#(myControllerBean.selectedItem)}"/>
<h:column/>
</h:dataTable>
where i can dynamicly choose property for person bean.
myControllerBean.selectedItem is string, and depending on its value i want the column to be person.name or person.age, ....
I know this can be solved with columns for every case and rendered attribute, but i'm looking for some better solution :)
Thanks in advance.

Try this:
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<c:set var="tmp" value="#{myControllerBean.selectedItem}"/>
Now set tmp in outputText as dynamic value:
<h:dataTable value="#{myControllerBean.persons}" var="person">
<h:column>
<h:outputText value="#{person[tmp]}"/>
<h:column/>
</h:dataTable>

Tip: resolve Bootstrap & Animate conflict

I built a wee navigation system for a set of pages showing Edge Animate (EA) compositions. The system was built using Twitter Bootstrap 3.
When I drew circles, they appeared smaller and slightly offset when in the browser as compared to EA.
The issue was a piece of CSS that comes with Bootstrap that has to be overridden:
Original CSS:
*:before,
*:after {
-moz-box-sizing: border-box;
box-sizing: border-box;
Override CSS:
*:before,
*:after {
-moz-box-sizing: inherit;
box-sizing: inherit;

as this post is rather old, I don't know if it would help original poster, but maybe someone in desperate need for a solution to this issue:
http://www.gwr.no/?p=593

ADF model : prevent refresh using invokeAction

hi
I'm trying to understand the Refresh and RefreshCondition properties of executables like methodIterator and invokeAction.
These executables come from the app_SRListPageDef.xml pageDefinition for SRList.jspx in the "Oracle ADF SRDemo Application":
<executables>
    <methodIterator id="findServiceRequestsIter"
                    Binds="findServiceRequests.result"
                    DataControl="SRPublicFacade" RangeSize="10"
                    BeanClass="oracle.srdemo.model.entities.ServiceRequest"/>
    <invokeAction Binds="findServiceRequests" id="tableRefresh"
                  Refresh="ifNeeded"
                  RefreshCondition="${(userState.refresh) and (!adfFacesContext.postback)}"/>
    
</executables>The same pageDefinition also contains this methodAction binding :
    <methodAction id="findServiceRequests"
                  InstanceName="SRPublicFacade.dataProvider"
                  DataControl="SRPublicFacade"
                  MethodName="findServiceRequests" RequiresUpdateModel="true"
                  Action="999"
                  ReturnName="SRPublicFacade.methodResults.SRPublicFacade_dataProvider_findServiceRequests_result">
      <NamedData NDName="userIdParam" NDValue="#{userInfo.userId}"
                 NDType="java.lang.Integer"/>
      <NamedData NDName="statusParam" NDValue="#{userState.listMode}"
                 NDType="java.lang.String"/>
    </methodAction>I added this navigateToSRList.jspx page to that application:
<?xml version='1.0' encoding='windows-1252'?>
<jsp:root xmlns:jsp="http://java.sun.com/JSP/Page" version="2.0"
          xmlns:h="http://java.sun.com/jsf/html"
          xmlns:f="http://java.sun.com/jsf/core"
          xmlns:af="http://xmlns.oracle.com/adf/faces"
          xmlns:afh="http://xmlns.oracle.com/adf/faces/html">
<jsp:output omit-xml-declaration="true" doctype-root-element="HTML"
              doctype-system="http://www.w3.org/TR/html4/loose.dtd"
              doctype-public="-//W3C//DTD HTML 4.01 Transitional//EN"/>
<jsp:directive.page contentType="text/html;charset=windows-1252"/>
<f:view>
    <afh:html>
      <afh:head title="navigateToSRList">
        <meta http-equiv="Content-Type"
              content="text/html; charset=windows-1252"/>
      </afh:head>
      <afh:body>
        <h:form>
          <af:commandButton text="show Open requests" action="GlobalHome">
            <af:setActionListener from="#{false}" to="#{userState.refresh}"/>
            <af:setActionListener from="#{'Open'}" to="#{userState.listMode}"/>
          </af:commandButton>
          <af:commandButton text="show Pending requests" action="GlobalHome">
            <af:setActionListener from="#{false}" to="#{userState.refresh}"/>
            <af:setActionListener from="#{'Pending'}" to="#{userState.listMode}"/>
          </af:commandButton>
        </h:form>
      </afh:body>
    </afh:html>
</f:view>
</jsp:root>This navigateToSRList.jspx page contains two buttons that will bring you to the SRList.jspx page. Both buttons explicitly set the userState properties refresh and listMode.
If I click the first button, I get to see the Open requests. If I click the second button, I get to see the Pending requests.
Because the tableRefresh invokeAction configures RefreshCondition="${(userState.refresh) and (!adfFacesContext.postback)}" and the buttons on my navigateToSRList.jspx explicitly set userState.refresh to false, I would expect this invokeAction NOT to be refreshed. (I checked the value -false- of userState.refresh using an expressionResolver.jspx page, see tip : resolve JSF expressions at runtime.)
(*) questions
- What causes the SRList.jspx page to show the expected data when using the buttons on navigateToSRList.jspx? I suspect it has something to do with the value of the statusParam NamedData in methodAction findServiceRequests that gets changed. The userState.listMode gets set by a af:setActionListener, this "changed methodAction parameter value" might trigger a refresh of the methodIterator. Can someone confirm this (from experience or with documentation)?
- Is it possible to prevent "executables to be refreshed" if "methodAction parameters were changed"?
many thanks
Jan Vervecken

Please see section "10.5.5 How to Use Refresh Correctly for InvokeAction and Iterator Bindings" of the ADF Developer's Guide for Forms/4GL Developers on the ADF Learning Center at http://www.oracle.com/technology/products/adf/learnadf.html for more information on this.
The information it contains is valid for Non-ADFBC data controls as well.

Oracle Express Tips/Whitepapers on Design and Performance ?

Hi all,
I was wondering if someone could please provide me with some information to
find
Articles / White Papers / Tips on Oracle Express, design and performance
tuning etc.,
Thanks for your help in advance.
RN
null

Following this link i thik that you can find what you are looking for.
http://metalink.oracle.com/metalink/plsql/ml2_documents.showNOT?p_id=131949.1&p_showHeader=1&p_showHelp=0
Bye Luigi

Tip : resolve JSF expressions at runtime

Similar Messages

Maybe you are looking for