Variables versus Request Scope

What are the best practices for using the variables scope
versus using the request scope when assigning variables.
In other words, when should I use <cfset variables.x =
'barf'> and when should I use <cfset request.x =
'barf'>?

SpiderFromMars wrote:
> What are the best practices for using the variables
scope versus using the
> request scope when assigning variables.
>
> In other words, when should I use <cfset variables.x
= 'barf'> and when
> should I use <cfset request.x = 'barf'>?
>
The variables scope is only accessible in the current
template. The
request scope is accessible in the current template and any
other
template, such as a custom tag or include file, that is used
to build
the current request.
I.E

<cfset variable.x = "foo">
<cfset request.x = "bar">
<cfoutput>#variable.x##request.x#</cfoutput>
<cf_myCustomTag>

<cfset variable.x = "bob">
<cfoutput>#variable.x##request.x#</cfoutput>

Similar Messages

Clearing variable from Request object

Hi everyone,
After getting value from request.getParameter("var"), I want to clear this "var" variable from request scope. So that in the next coming statements if i again call the same request.getParameter("var") statement than it must return null
So how to handle this issue of clearing certain variable from request scope or flushing the whole request object

I don't know what you are trying to do but it sounds confused. I would suggest you read the parameter once, at the beginning of the code. Store it in a variable and use that variable as necessary. If you still need help then would you explain what you are trying to achieve here.

Forwarding a variabe in request scope

When i am trying to forward a variable in request scope along with action, i am not not able to retrieve the value in action class.As in config.xml one action will call other action in LayoutConfig.xml I couldnt retrieve the vaue in action class.So anyone please suggest me in this criteria.
regards
Anuradha

Hi Steve,
Try to pass your parameter in layoutconfig.xml instead of in Java Script function of JSP Page.
JSP:
document.forms[0].action='<isa:webappsURL name="/b2c/transactiondetails.do"/>?transId='+transvalue;
documen.forms[0].submit
config.xml
<action path="/b2c/transactiondetails" forward="UIArea : transactionDetails"/>
LayoutConfig.xml
<UIComponent name="transactionDetails" action="/b2c/getTransactionDetails.do"
title="b2c.transactiondetails.title"/>
config.xml
<action path="/b2c/getTransactionDetails" type="com.sap.isa.isacore.action.loyalty.ZGetTransactiondetailsAction">
<forward="succecc" path="UIInclude:/b2c/transactionDetails.inc.jsp"/>
</action>
Try below it may work.
JSP:
document.forms[0].action='<isa:webappsURL name="/b2c/transactiondetails.do"/>;
documen.forms[0].submit
config.xml
<action path="/b2c/transactiondetails" forward="UIArea : transactionDetails"/>
LayoutConfig.xml
<UIComponent name="transactionDetails" action="/b2c/getTransactionDetails.do?transId="transvalue" title="b2c.transactiondetails.title"/>
config.xml
<action path="/b2c/getTransactionDetails" type="com.sap.isa.isacore.action.loyalty.ZGetTransactiondetailsAction">
<forward="succecc" path="UIInclude:/b2c/transactionDetails.inc.jsp"/>
</action>
You will get transld value in action class ZGetTransactiondetailsAction and get the attribute from request object by getParameter/getAttribute method also you can set this parameter/attribute again in request object in ZGetTransactiondetailsAction and then retrieve it again on transactionDetails.inc.jsp page from request object.
If getAttribute do not work try getParameter method.
I hope this will help you.
eCommerce Developer

When should use request scope

hi
i don't know when i should use request scope, the example is use session scope always.
Can anyone help me?
thanks!

SpiderFromMars wrote:
> What are the best practices for using the variables
scope versus using the
> request scope when assigning variables.
>
> In other words, when should I use <cfset variables.x
= 'barf'> and when
> should I use <cfset request.x = 'barf'>?
>
The variables scope is only accessible in the current
template. The
request scope is accessible in the current template and any
other
template, such as a custom tag or include file, that is used
to build
the current request.
I.E

<cfset variable.x = "foo">
<cfset request.x = "bar">
<cfoutput>#variable.x##request.x#</cfoutput>
<cf_myCustomTag>

<cfset variable.x = "bob">
<cfoutput>#variable.x##request.x#</cfoutput>

Passing bean as attribute to servlet in request scope

Hello,
I want to pass a bean from a jsp to my controller servlet. As I understood, as long as I can give the bean 'request' scope, then I should be abble to access the bean, as an attribute in the doPost / doGet method of my servlet. However, when I try to get the bean in the servlet, its always null.
I am aware that request scope beans don't loose their values when passing to other JSP's , but what about passing to servlets?
I dont want to use a session scoped bean as I believe this should be possible with a request scoped variable.
<%-- vwLogon.jsp --%>
<jsp:useBean id="viewBean" class="com.alto.common.ViewBean" scope="request">
     <jsp:setProperty name="viewBean" property="viewName" value="/vwLogon"/>
</jsp:useBean>
<html>
<body>
<h2>Enter Name</h2>
<form method="GET" action="controller">
     Enter your name:<input type="text" name="vwLogon_User_txt" value=""/>
     Enter your password:<input type="secret" name="vwLogon_Password_txt" value=""/>
<input type="submit" name="vwLogon_Logon_Btn" value="Logon"/>
</form>
</body>
</html>
------------------------------- controller servlet
public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
ViewBean viewBean = (ViewBean)req.getAttribute("viewBean");
String strURL = new String("");
if (!(viewBean==null)) {
strURL = viewBean.getViewName();

A request/response pair is one communication between the client browser and the web server. A submit form action generates a new request.
In this instance you have two requests:
1 - load login page
2 - submit login page
The point of being able to give a bean request scope, is so that you can use jsp:forward, or jsp:include to pass on the request, and the bean as well.
In your case, a session bean is probably called for, as you have 2 request/responses in your session.
Hope this clears things up a little.
Cheers,
evnafets

Using a request scope object in a javascript function

Hello,
is there a way to obtain a reference to a request scope attribute in a javascript function?
or after using <jsp:useBean id="myBean" ...>, how do I pass the "myBean" object to a javascript fuction?
Thanks for any help.
E-

ok, thanks...this is working for a string property of a bean... but I get an 'invalid character' error when I want to create an actual reference to the bean object itself.
here is the jist of what I need to get working... myBean has a property 'listItems' that is a Vector of listBeans.
function buildList() {
var myBean = <%=request.getAttribute("mybean")%> ;
// get referenence to the Vector property listItems
var list = myBean.getListItems();
// now I want to iterate the list and use the properties of the list beans
for (x = 0 ; x < list.size() ; x++ ) {
var listBean = list[x];
var foo = listBean.getFoo();
// need to use foo to populate a hierarchical list
can I do this in JavaScript??? do I need to cast the classes to the variables?

How to persist a data in request scope

Hi All...
I am using JDeveloper Studio Edition Version 11.1.1.0.2.In my managed bean (backing bean scope), I have a variable say " private loginname;" with a global scope and corresponding getter and setter methods inside the backing bean.How can I persist my data in request scope not using a session variable.
Thanks in advance
Dinil Mithra

Hi all,
I need to access the data in the request scope( Not in session scope ). ie, after the command button's action or action listener ,I loose the persistence of my variable.But the same time persistence of the textfield exists.I need to implement the persistence like textbox or ADF component
Thanks for your response
Dinil Mithra
Edited by: Dinil Mithra on May 21, 2009 1:25 AM

Seting a JSp variable to session scope in JSp page itself

Hi,
I have code like this
<HTML>
     <HEAD>
          <TITLE>Change Password</TITLE>
          <LINK REL ="stylesheet" TYPE="text/css" HREF="stylesheet/vclinical.css" TITLE="Style">
</HEAD>
<BODY>
<form name="form">
<select name="ss" onChange="this.form.qq.value=options[selectedIndex].value;getit()">
<option value=1>ss1</option>
<option value=2>ss2</option>
</select>
<input type="text" name="qq" value="">
<%
String asd=request.getParameter("qq");
session.setAttribute("Stored", asd);
System.out.println("value is"+asd);
%>
</form>
</BODY>
</HTML>
here i want to set value of a JSP variable qq to session scope and here i am not invoking any servlet i want value of qq in next JSP page i am not submitting the page so how i can handle this. this code does not work so please tell me how to do this i am using struts frame work

if you are using the struts framework, then you can make an ActionForm with getters and setters for the stuff that you are writing in the JSP i mean the radio buttons and text boxes etc
from that action form you can get the values any time any where
you just need to enter some thing like below in the struts-config.xml file
<form-bean name="the action form name" type="package name.Actionform name" />
<action path="/controller " type="package name.controller name" name="Action form name" scope="session">
you can either put the action form in request scope or session scope

Getting bean from request scope

Hi,
I am new to JSF and unfortunately I am running into a problem that I am not entirely sure about. I look in other forums and what I am doing looks right but I am not getting the desired result.
In my faces-config.xml file I have a managed bean defined as follows:
<managed-bean>
    <managed-bean-name>LogIn</managed-bean-name>
    <managed-bean-class>lex.cac.tables.RefUsers</managed-bean-class>
    <managed-bean-scope>request</managed-bean-scope>
</managed-bean>I then have a log on page with a form which contains a user name and password field. The tags are defined as
<h:inputText immediate="false" value="#{LogIn.username}" /> (for username) and
<h:inputSecret immediate="false" required="true"
                               value="#{LogIn.password}" /> (for password)
When I submit the form the web app navigates to a jsp page which attempts to do validation against a database.
The first step though is retrieving the object which is suppose to be in request scope.
I attempt the following but I get back null which causes a NullPointerException. Why can't if find the bean?
ExternalContext ec = FacesContext.getCurrentInstance().getExternalContext();
Map params         = ec.getRequestParameterMap();
params.get("LogIn"); //null is returned hereWhat am i doing wrong? Can someone please help.
Thanks in advance,
Alex.

Something like that:
FacesContext fc = FacesContext.getCurrentInstance();
RefUsers LogIn = (RefUsers)fc.getApplication().createValueBinding("#{LogIn}").getValue(fc);
String username = LogIn.getUsername();
String password = LogIn.getPassword();

How to get detailStamp working in an af:table when using request scope ?

<af:table var="row" id="t1" value="#{listUsers.users}" summary="Userlist" binding="#{listUsers.ATable}" [...]
<af:column sortable="false" headerText="Username" id="c13" filterable="true">
<af:outputText value="#{row.username}" id="ot13"/>
</af:column>
<f:facet name="detailStamp">
<af:panelFormLayout rows="4" labelWidth="33%" fieldWidth="67%" inlineStyle="width:795px" id="pfl1" labelAlignment="start" >
<af:group id="g1">
<af:panelLabelAndMessage id="plamNumber" label="Number" for="number">
<af:outputText value="#{row.address.number}" id="number"/>
</af:panelLabelAndMessage>
I feel there is nothing special with this.
But I've tested with 2 rows in my table and when I disclose rows, I get random results :
sometimes I get the details related to the row disclosed, but sometimes I get the details of the other row.
I've read several posts on the subject but none really helpful.
Another problem ; I've noticed that when I disclose or close a row, getUsers() is called, this method fetch the data from the DB, any way to prevent it ?
For the second problem, the solution I see would be to : change scope of listUsers to session instead of request, fetch from the DB only when "refresh", not when "detailStamp",
but I've no clue on how to actually do the "only when part"
Thanks in advance,
JP

Ok when I change the scope of ListUsers to session it's "ok" since I only load the list from the DB once (just like the demo that does not have this problem since the demo does not use the DB)
When I change the scope for request and that the page is refreshed then the object ListUsers is "recreated" and the data reloaded : that's the expected behavior
So I prefer to have the scope sets to request
The problem is that when a user disclose/close a detailstamp and that the scope is set to request,
then the data is reloaded from the DB
because apparently this event acts like a "refresh"
because this event (disclose/close) cause the destruction of what is in the request scope ...
That's my understanding, probably few mistakes, I'm beginning with ADF/JSF
It seems that when I load the data from the DB, it's not always in the same order, causing the problem itself probably, which is not ADF related BUT ;
what I would like to know is how to (elegantly) prevent the event of "disclose/close" to act like a "refresh" ?
Because even if I fix the "not ADF related problem" (if there is one), loading the list from the DB each time, appears really useless and the DBA won't like me !
A solution could be to leave the session scope, but then my question would be ;
*how to know I've to reload from the DB ?"
I could just "reload it on page load", seems ok to me but
I'm not sure it's the best, I would like to have your opinion, I've found this article for the "on page load" part ;
http://groundside.com/blog/DuncanMills.php?title=adf_executing_code_on_page_load&more=1&c=1&tb=1&pb=1
Thanks,
JP

Validation error while trying to change a value in a request scope bean

- JBoss 4.2.3.GA
- JSF 1.2_09-b01-BETA1 (Mojarra)
- Java 5 Update 17
Hello, everybody!
I'm having the following problem in my JSF web application:
I have a request scope backing bean. The first time this bean is loaded (I check
this with the ResponseStateManager.isPostBack() method) I fill a list of SelectItem
instances that are to be displayed in the JSF page in a +<h:selectOneMenu>+ component.
The list goes, of course, to the +<h:selectOneMenu>+'s +<f:selectItems>+ facet child
component. In the constructor I also define the value that goes to the value property
of the +<h:selectOneMenu>+ component. This value is a property in the backing bean, as
is the list of SelectItem instances. Until now we have something like this:
The backing bean declaration in faces-config.xml:
<managed-bean>
    <managed-bean-name>solicitacaoGeral</managed-bean-name>
    <managed-bean-class>br.urca.solicitacoes.web.PaginaSolicitacaoGeral</managed-bean-class>
    <managed-bean-scope>request</managed-bean-scope>
</managed-bean>
The relevant parts of the JSF page:
<h:form id="form">
    <h:selectOneMenu value="#{solicitacaoGeral.setorOrigem}" id="foco">
        <f:selectItems value="#{solicitacaoGeral.setoresOrigem}" />
    </h:selectOneMenu>
</h:form>
The relevant parts of the backing bean class:
public class PaginaSolicitacaoGeral
    private final List<SelectItem> fSetoresOrigem = new ArrayList<SelectItem>();
    private Setor fSetorOrigem;
    public PaginaSolicitacaoGeral()
        if (primeiraExibicao()) // First load (!ResponseStateManager.isPostBack())
            // Fill fSetoresOrigem...
            fSetorOrigem = ...
        else // Page submitted
            // Read below...
    public List<SelectItem> getSetoresOrigem()
        return fSetoresOrigem;
    public Setor getSetorOrigem()
        return fSetorOrigem;
    public void setSetorOrigem(Setor setorOrigem)
        fSetorOrigem = setorOrigem;
    private boolean primeiraExibicao()
        String idFerramentaExibicao =
            FacesContext.getCurrentInstance().getViewRoot().getRenderKitId();
        ResponseStateManager gerenciadorEstadoResposta =
            RenderKitUtils.getResponseStateManager(
            FacesContext.getCurrentInstance(), idFerramentaExibicao);
        return !gerenciadorEstadoResposta.isPostback(
            FacesContext.getCurrentInstance());
}But when the user submits the form and the bean constructor is called again
(this time the method ResponseStateManager.isPostBack() returns true ),
in the else block in the constructor above, I need to fill fSetoresOrigem with
other values and also the fSetorOrigem field because, of course, the fSetorOrigem
field has to be a valid value that exists in the new fSetoresOrigem list.
JSF is not complaining about the change to the list items, but it is complaining
to the change to the fSetorOrigem field (the list value), even though it is a
valid value present in the list. So I'm getting this error message:
08:23:54,312 INFO [lifecycle] WARNING: FacesMessage(s) have been enqueued, but may not have been displayed.
sourceId=form:foco[severity=(ERROR 2), summary=(form:foco: Validation Error: Value is not valid), detail=(form:foco: Validation Error: Value is not valid)]I suppose that JSF is comparing the new value of the field fSetorOrigem with the value
it has in the view state. As the value is different it is raising the error. That's
what I suppose. But am I not able the change the value in the postback? I've already
checked and the value is valid. It corresponds to a value that exists in the list.
I really need a solution to this problem as I'm stuck with this and can't proceed until
I find a solution to this. What I am doing wrong and how can I solve this?
Thank you very much.
Marcos

BalusC wrote:
It is comparing the selected value against the List<SelectItem> returned by getSetoresOrigem() as it is during the apply request values phase of the form submit request.Ok. That's what I supposed JSF was doing.
BalusC wrote:
If the selected value isn't in there, then you will get this error.I can understand this, but is this right? As I said, the old value isn't really there because I changed the list values to new ones. But the new value (the value of fSetorOrigem ) corresponds to a value that exist in the new list items, so a valid value. So JSF is not considering that I also changed the list, not just the value. It is comparing the new value with the old list, not the new one. Acting like this JSF is making the page looks like a static HTML page, not a dynamic one. If I can't change the list and the value, what's the point of that? In my point of view I'm not doing anything wrong, I'm not violating any JSF rules.
Marcos

Have a backing bean in request scope; need to access parameters sent to it

I have a request scope backing bean in my app, 'projectBean'. This has a property called 'id'.
/** in request scope in faces-config.xml */
projectBean {
    id               // set by the param from the previous page
    downloadAction() // activated by commandlink, depends on id
}There is another backing bean in session scope called 'projectListingBean', which has a dataTable that lists a bunch of projectBeans. In this 'projectListingBean', I can click on any row. That row, when clicked initializes a 'id' parameter, which is then passed to the new 'projectBean'. 'projectBean' then initializes itself based on the id.
In the jsp page backed by 'projectBean', I also have a link to download something specific to that 'projectBean'. Naturally enough, I have a commandlink with actionBinding to a method in my 'projectBean', downloadXXXAction().
The problem arises because the downloadXXX() method relies on a 'id'. Remember, this id was orinigally set 2 requests back from the datatable. Since the page backed by 'projectBean' is in request scope, the id is lost, and my method call doesn't work. I tried changing the scope of 'projectBean' to session, but JSF complains that I already setting the 'id' property as a param, I can't set the whole managed bean to something 'higher' like session.
Of course, the ideal fix to this probelm would be the ability to have beans in page scope, but what other ways (hacks??) are there to get around this?

Hi, I'm posting some code snippets if it helps with understanding the problem.
faces-config.xml:

<managed-bean>
     <managed-bean-name>projectListingBean</managed-bean-name>
     <managed-bean-scope>session</managed-bean-scope>
     <managed-property>
          <property-name>projectBeans</property-name>
          <property-class>java.util.List</property-class>
          <list-entries>
               <value-class>
                    com.sun.sleuth.omcmweb.view.bean.ProjectBean
               </value-class>
          </list-entries>
     </managed-property>
</managed-bean>

<managed-bean>
     <managed-bean-name>projectBean</managed-bean-name>
     <managed-bean-class>
     </managed-bean-class>
     <managed-bean-scope>request</managed-bean-scope>
     <managed-property>
          <property-name>projectId</property-name>
          <property-class>java.lang.String</property-class>
          <value>#{param.projectId}</value>
     </managed-property>
</managed-bean>projectlsting.jsp (page backed by projectListingBean)
<h:dataTable value="#{projectListingBean.projectBeans}"
     var="projectBean" ...>
     <h:column>
          <f:facet name="header">
          </f:facet>
          <h:commandLink action="#{projectListingBean.viewProjectSUmmary}">
               <h:outputText value="#{projectBean.projectId}" />
               <f:param name="projectId" value="#{projectBean.projectId}" />
          </h:commandLink>
     </h:column>
</h:dataTable>projectsummary.jsp (page backed by request scoped projectBean)
<h:commandLink action="#{projectBean.assessmentAction}" value="..." />
...Flow:
projectlisting.jsp (projectListingBean - session) -param id passed->
projectsummary.jsp (projectBean - request) -commandLink clicked and id lost-->
projectSummary.jsp (projectBean - request)

Creation of a Managed Bean in Request Scope?

Is there an easy way to create an instance of a managed bean (configured in faces-config.xml) that was configured to be in the Request scope?
If a JSP refers to it by id, then it will be there.
However, when the JSP does not refer to it, it will not be in the request. I find I need to generate it anyway to use it from within another Managed Bean. I can extract out the faces-config information from the application map (available from FacesContext) and build it manually -- but this ties me to a particular JSF implementation (and probably version, too).
Is there a more standardized way to do this?
Thanks,
ken

BTW -- I mean to do this from within Java code (not jsp), and the page being rendered does not have a direct reference to the request-scoped managed bean via value binding.

Command Link in the af:table Component can not Work in the Request Scope

Actually, the problem is that when we click on the command link, the action method #{overview.goToLinkAction} is not triggered.
Here is the codes of action method "goToLinkAction" on the backing bean:
public String goToLinkAction() {
String linkString = (String) AdfFacesContext.getCurrentInstance()
.getProcessScope().get("linkString");
System.out.println("Link String is: " + linkString);
return "";
The data object list "listOfTransefer" for af:table is composed first time when the page is initialized.
public void onPageLoad() {
this.listOfTransfers = composeListOfTransfers();
But when the commandlink or commandbutton is clicked to pose the form, this onPageLoad method is ignored by using PagePhaseListener:
public void beforePhase(PagePhaseEvent event) {
FacesPageLifecycleContext ctx =
(FacesPageLifecycleContext)event.getLifecycleContext();
if (event.getPhaseId() == Lifecycle.PREPARE_MODEL_ID && needReload()) {
bc = ctx.getBindingContainer();
onPageLoad();
bc = null;
public final boolean needReload() {
if (!isPostback())
return Boolean.TRUE;
else
return alwaysReload();
protected boolean isPostback() {
return Boolean.TRUE.equals(resolveExpression("#{adfFacesContext.postback}"));
That means the method "onPageLoad()" may not be invoked when the commandlink is clicked.
Is there any way to resolve this problem without changing the scope of the backing bean to "session"?
Your response will be very helpful for us.
Thanks

Hi,
if you implicitly say that this works if the managed bean is in session scope then the problems seems to me that one of your evaluation criterias is reset in the request scope, which I think most likely is the needReload() method. Did you add debug statements to the methods to see where exactly it gets stuck?
Frank

Work around for request scope for Listitems-working

Hi finally I got some work around solution for Listitems working with request scope, if any suggesion welcome, below is the small code of jsp and bean.
<h:selectOneMenu id="ownerListMenu" value="#{pc_trackingSearchPage.trackingSearchPageBean.selectedOwner}">
                                        <f:selectItems value="#{pc_trackingSearchPage.trackingSearchPageBean.ownerList}" />
                                   </h:selectOneMenu>
I used onPageLoadBegin() and onPagePost(),
first on PageLoad - I am loading the List from DB, its displaying perfect.,
than on pagePost -> I am setting the value ->ownerList.add(new SelectItem(getOwnerListMenu().getSubmittedValue().toString(),getOwnerListMenu().getSubmittedValue().toString()));
------->here is the getOwnerListMenu method.
     public HtmlSelectOneMenu getOwnerListMenu() {
          if (ownerListMenu == null) {
               ownerListMenu =
                    (HtmlSelectOneMenu) findComponentInRoot("ownerListMenu");
          return ownerListMenu;
so this way the List will not be empty what ever the user selectes it will be their, as i am setting key and values as same, so in submit method,
i am getting the selected keys and going back to backend getting results displaying on other page,
--->this will work only if they don't need the list , if they want to display the list again, they have to load freshelly.
I hope it will give some solution for request scope, if the data is huge and not to save on the session for navigation purpose.
suggestions welcome.
Thanks
srikanth
Message was edited by:
srikanthg

Apperently iTunes 11 is not affected (Apple stil makes iTunes11 for the 14 yr old Microsoft XP OS, but not for anything PPCs can run. Go figure)
"Next door" to Steve was metaphoric, he lived in Los Altos, about 15 miles away, but he cast a big shadow!
On 9.2.1/10.4.11 differences, some time in the past someone selected 'save file' and checked the box 'don't ask again' on your computers dialog box. That's why you're not given a choice wih the file downloads. I would think that selection should be able to be reversed.
iTunes 9.2.1/OS10.4.11 puts those downloaded URLs into the Music Libary of iTunes, no matter if it's opened directly, or you click on the file on your desktop. You can create a new playlist, highlight the selection in the Music Libary, and drag it to your new playlist to keep alll the steaming URLs together. NOTE, this only creates an alias, the URL copied by iTunes must remain in the Music Libary. You can then delete the the files on the desktop, if you want. I did multiple stations this way in 9.2.1, they all show in either the new playlist created, or in the Music Libary, and remain after the desktop files are deleted and trash emptied.
You can switch sations by double clicking them. Another note, all the URLs were all from vtune.
I hope this helps.
PS, I forgot how clunky Tiger is compared to Leopard...

Variables versus Request Scope

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