PageContext and EL ?

Hello All,
Can some explain me how this below EL expression works:
In my jsp when i do
${pageContext.session.new}
Output: trueAs far as i know, pageContext does a getSession() call, but then the session object doesnt have a getNew() property, it is isNew().
So why do i still see value as "true" ??
Please advise,

It follows the javabeans specification.
"new" is a boolean readonly property exposed by the method "boolean isNew()"
All boolean properties (note the lower case b) have their "getter" with the "is" prefix rather than "get".

Similar Messages

PageContext and HttpServletRequest error... Help!

Hi All
I have a java file which make use of PageContext and HttpServletRequest classes(I assume they are classes). But on compiling, I m getting the errors
cannot find symbol
symbol : class PageContext
cannot find symbol
symbol : class HttpServletRequest
The errors repeat a few times because variables have been created of type PageContext and HttpServletRequest and are being passed to functions.
I have imported both the classes using
import javax.servlet.*;
import javax.servlet.jsp.PageContext;
import javax.servlet.http.HttpServletRequest;
But on navigating to javax.servlet, I found that NEITHER PageContext NOR http folder ( the folder itself) were present.
I assume these are standard classes, should they already exist or should I create them.
Please help...
Thanks a lot...
Edited by: mooey_tom on Jun 12, 2008 7:27 AM

OK, you have to use the classpath option in javac.
First, locate the Tomcat installation directory. Then, add servlet-api.jar and jsp-api.jar to the classpath. If there is no Tomcat in the server you are using to compile you will need to upload these files.
I'm at work and I don't have a Linux box at hand, but this is an example in windows.
C:\>javac -classpath "c:\Program Files\Apache Software Foundation\Apache Tomcat 6.0.14\lib\servlet-api.jar;c:\Program Files\Apache Software Foundation\Apache Tomcat 6.0.14\lib\jsp-api.jar" Test.javaIn Linux you will have to use *:* instead of *;* to separate the jar paths.
Another option is to set the CLASSPATH variable. For example:
export CLASSPATH=$CLASSPATH:/path/to/tomcat/lib/servlet-api.jar:/path/to/tomcat/lib/jsp-api.jarAnd then compile normally.
Let me know if it works
Edited by: andres_dominguez2 on Jun 13, 2008 9:25 AM
Edited by: andres_dominguez2 on Jun 13, 2008 9:27 AM

Difference between PageContext and HttpServletRequest

folks i was reading that when JSP Expression language searches in this order
PageContext, then HttpServletRequest, then HttpSession, and then ServletContext
what is the difference between PageContext and HttpServletRequest because i think both are same???

PersianKamran wrote:
what is the difference between PageContext and HttpServletRequest because i think both are same???Please read the API javadocs:
[javax.servlet.jsp.PageContext|http://java.sun.com/javaee/5/docs/api/javax/servlet/jsp/PageContext.html]
[javax.servlet.http.HttpServletRequest|http://java.sun.com/javaee/5/docs/api/javax/servlet/http/HttpServletRequest.html]
If, after studying the documentation, you still think these represent the same class of object, please explain why and we can help clear up any remaining confusion.
Thanks!
~

Accessing pageContext in a bean

I want to access the pageContext in a bean. please tell me how to do it...
Thanks in advance...

Pass the PageContext in to the Bean:
<jsp:useBean id="myBean" scope="session" class="MyBean" />
<% myBean.setPageContext(pageContext); >
and in MyBean:
public class MyBean {
javax.servlet.jsp.PageContext pageContext;
public void setPageContext(javax.servlet.jsp.PageContext inPageContext) {
this.pageContext = inPageContext; }
....etc

How do I add an included jsp to my project and not get a compile error?

Hi,
I have a project with some included jsp's however if I add them to the project, when I build I get a compile error as the jsp uses variables from the calling jsp.
Any ideas on how to get round this.
Thanks
DM

There are two main ways that I deal with this problem (yeah, it sucks, but it sort of makes sense that it happens...) (I presume you're talking static include here...)
#1 - name the included file with an extension that JDev will not try to compile (.jspf - for JSP Fragment - is common) Then it will be compiled in with the including page, but won't gag the project compilation. Advantage - it works, and you find out at compile time if you hosed up the variable reference. Disadvantage: JDev tries really, really, really hard to keep you from naming a JSP file with an extension of .jspf I normally create the .jsp file in JDev, remove it from the project, rename the file outside of JDeveloper, then add it back to the project - pain in the butt, but it works (and you probably aren't building scads of these included files...)
#2 - add the variable to be referenced to the pageContext implicit object as an attribute in your including page (ex, <% pageContext.setAttribute("myVar", myVar); %>), then reference that attribute in your included JSP (ex, <%= pageContext.getAttribute("myVar") %>) . It will compile fine (as the compiler has no way of knowing if the pageContext attribute actually exists, it just sees that the syntax is good and motors along merrily. Advantage: don't have to have differently named JSP files (which isn't actually a big deal). Disadvantage: You hvae to add the variable to the pageContext (and you have to always add Object derivatives, as primitives won't go into a hash) and you don't find out if you screwed the variable up until runtime (when it tries the getAttribute, which could return null if you didn't properly set it to start with) vs at compile-time w/ the direct reference.
HTH!
Jim

Custom taglibs and XScript

Hi guys,
To simplify my jsp's in a portal 8.1 application I am considering
implementing some custom tags for often used constructs.
In this task I would like to pass some objects to the task-handler
and wonder if I can utilize dynamically attributes through the use
of XScript expressions.
Basically I want to implement a custom tag that will allow me to
do the following:
<custom:mytag value="{container.item.username}"/>
and then in the handler resolve {container.item.username} to
the correct object.
If not, how can I solve the issue of passing the object to my
custom tag?
TIA,
Claus Ljunggren

Eddie,
Thank you very much for your reply.
Actually I startet out using the exact method you suggest, but I found a
twist to make the solution far more elegant (in my oppinion that is).
My primary reason for creating the tags was to get rid of all those annoying
scriptlets. So naturally I didn't like the <%=%>'s! But it turns out that I
don't need them in my jsp's at all.
The netui-data:getData tag puts the value in the pageContext and the
pageContext is directly available from the TagSupport class! This means that
I can look the value up from the tag-handler instead of the jsp page. So all
I have to do is pass the name of the variable in the pageContext to my
tag-handler. End result beeing :
JSP:
<netui-data:getData value="{container.item.username}" resultId="username"/>
<custom:mytag resultId="username"/>
TAG-HANDLER:
public int doStartTag() {
String value = (String) pageContext.getAttribute(resultId);
Not the XScript vision I had, but close enough ... for now ;-)
Regards,
Claus Ljunggren
"Eddie O'Neil" <[email protected]> wrote in message
news:[email protected]...
Claus--
In 8.1, NetUI didn't expose a JSP tag SDK and thus we're not supportingbuilding custom tags that
extends NetUI ones.
That being said, there are some who are doing this, but there won't bea migration path for it
going from 8.1.x to 9.0.
The same functionality could be accomplished through a combination ofthe NetUI getData tag and
runtime expressions on your custom tags. For example:
<netui-data:getData value="{container.item.username}"resultId="theValue"/>
<custom:mytag value="<%= pageContext.getAttribute(theValue) %>"/>
This would also set your tags up well for the next WLS version and forNetUI in Beehive where we've
started using JSP 2.0 EL for expressions.
Hope that helps!
Eddie
Claus Ljunggren wrote:
Hi guys,
To simplify my jsp's in a portal 8.1 application I am considering
implementing some custom tags for often used constructs.
In this task I would like to pass some objects to the task-handler
and wonder if I can utilize dynamically attributes through the use
of XScript expressions.
Basically I want to implement a custom tag that will allow me to
do the following:
<custom:mytag value="{container.item.username}"/>
and then in the handler resolve {container.item.username} to
the correct object.
If not, how can I solve the issue of passing the object to my
custom tag?
TIA,
Claus Ljunggren

How to get accessed to pagecontext in a tag file in JSP2.0

I am writing a custom tag using JSP 2.0 to clean up the JSP pages for a big website.
Now a question comes up. I need to access pageContext variable in my tag file since I need to get the bean using a lookup method. I know in JSP2.0 there is jspContext implicit object instead of pageContext. But this is not the end of the story.
then I read Denis' post. and his solution are these two line codes:
<%
PageContext pageCtx = (PageContext)jspContext;
tagBean.init(pageCtx);
%>
I am confused here what the tagBean here. Is that a webBean? and how can I get this object in my tag so that I could initialize the pagecontext and reference it?
thanks in advance

The lookup method just returned me a null. So I believe that there is
some trick behind this simple cast.First I would double check your basic assumptions.
Is the attribute you are looking up actually there? That would be a simpler explanation for why the lookup method returned null.
Try a jspContext.findAttribute() , specific request/session.getAttribute() to see if you actually retrieve anything.
Also be aware that the RequestUtils.lookup() method has been deprecated in Struts 1.2, in favour of org.apache.struts.taglib.TagUtils.lookup().
Cheers,
evnafets

Get pageContext in a tag file

How can I get pageContext variable in a tag file? I'm trying something like
<%tagBean.init(pageContext);%> and compiler says it cannot resolve pageContext.
Thanks for help.
Denis Krukovsky
http://dotuseful.sourceforge.net/

<%tagBean.init(pageContext);%>looks more like a jsp scriptlet rather than a tag class in which case you shouldnt be getting a compiler error as pageContext is a implicit jsp object of type javax.servlet.jsp.PageContext and hence avbl by default to all jsp pages.
Now if you are coding a tag class and your tag extends TagSupport, pageContext is again a protected super class variable.
However if your tag class implements the tag interface (brave path :)?), you should build the pageContext object yourself
Cheers,
ram.

PageContext Vs ServletContext

Can anybody explain me what is the Difference between PageContext and ServletContext.

Write your own Configuration file for your application:
Define the variables in your WEB-INF\ web.xml file
<context-param>
<param-name>driverName</param-name>
<param-value>org.gjt.mm.mysql.Driver</param-value>
</context-param>
In JSP use,
<%= application.getInitParameter(�driverName�) %>
or
<%=context.getInitParameter("driverName")%>
--This is one of the advantage of ServletContext,, in this approach u can use the property of driverName in a application... ie the scope of the property value available for the entire application..
but In the case of PageContext.....the scope of the variable avialble within the current page and forwarded page.
This example uses attributes to save and retrieve data in each of the four scopes:
<% // Check if attribute has been set Object o = pageContext.getAttribute("com.mycompany.name1", PageContext.PAGE_SCOPE);
if (o == null) {
// The attribute com.mycompany.name1 may not have a value or may have the value null }
// Save data// PAGE_SCOPE is the default for all JSP pages
pageContext.setAttribute("com.mycompany.name1","value0"); pageContext.setAttribute("com.mycompany.name1","value1", PageContext.PAGE_SCOPE);pageContext.setAttribute("com.mycompany.name2","value2" , PageContext.REQUEST_SCOPE);pageContext.setAttribute("com.mycompany.name3","valu e3", PageContext.SESSION_SCOPE);pageContext.setAttribute("com.mycompany.name4","valu e4",PageContext.APPLICATION_SCOPE);%>
<%-- Show the values --%>
<%= pageContext.getAttribute("com.mycompany.name1") %>
<%-- PAGE_SCOPE --%>
<%= pageContext.getAttribute("com.mycompany.name1",
PageContext.PAGE_SCOPE) %>
<%= pageContext.getAttribute("com.mycompany.name2", PageContext.REQUEST_SCOPE) %>
<%= pageContext.getAttribute("com.mycompany.name3", PageContext.SESSION_SCOPE) %>
<%= pageContext.getAttribute("com.mycompany.name4", PageContext.APPLICATION_SCOPE)%>

Scope and context.. ???

Hi...
Can any one clarify me whats the difference between a context and a scope ???
Ex. whats is difference between pageCOntext and pageScope ?

From the API: A PageContext instance provides access to all the namespaces associated with a JSP page, provides access to several page attributes, as well as a layer above the implementation details.
http://java.sun.com/j2ee/1.4/docs/api/javax/servlet/jsp/PageContext.html
With regards to Servlets/JSP, there are four "scopes" for storing attributes in: page, request, session and application. When talking about a scope normally refers to just ONE of those namespaces.
People sometimes do use pageContext and pageScope interchangeably because the method call pageContext.setAttribute() sets an attribute into the pageScope. But the pageContext is much more than that.
Hope I haven't confused you too much
Cheers,
evnafets

Help needed in JSP Expression Language

Hi all,
I have been working for JSP Expression Language Sample execution since past 5 days. I am using the application server as "Jboss Server" and web server as "Tomcat".
I have been included the jsp-api.jar file in my lib directory of application server as well as source folder's lib directory.
When i am trying to build the source code, i am getting this build error.
[javac] D:\eclipse\workspace\esolvProject\development\src\com\esolv\taglibs\
web\classes\SetSupport.java:186: cannot resolve symbol
[javac] symbol : method getExpressionEvaluator ()
[javac] location: class javax.servlet.jsp.PageContext
[javac] ExpressionEvaluator evaluator = pageContext.getExpressionEvaluator();
In my jsp-api.jar , there are two classes called,
PageContext and JspContext, Both are abstract classes.
PageContext inherits JspContext class. JspContext class have the method getExpressionEvaluator() , returns ExpressionEvaluator.
PageContextImpl - class . it has been called internally when we are trying to call PageContext class. In PageContextImpl class, there is one comment before, the method's definition. that is
" Since JSP 2.0 "
But we have the JSP 2.0 version. But it won't work.
Please help me ont this.
Thanks in Advance,
Natraj

>
If the pblm was due to setting the classpath.
The error should be showed for all files in the jar
file.
why i am getting the error for particular method ?
it is accessing the other methods of same class
'JspContext' . but it is not accessing that method.
Thats my question.
Just check that your .jar file is 2.0 compliant and that you do not have any other jars(for servlet or jsp api) in the classpath.
Probably you have an older version of .jar file in your path. So the errors will appear only for those methods that have been added since 2.0, all other methods would compile fine.
Please tell me the jar files to work out the
expression language. so that i can cross check my
list of jars.Hmmm...I dont use jboss. In tomcat the jar file name is jsp-api.jar. But it would have been the same even for jsp1.1, going by jar file names wouldnt help. Just look at your cp as if with a microscope to identify redundant jars.
cheers,
ram.

Co-operating tags? ... cooperating siblings, not ancestors

i have a JSP with a few sibling custom tags:
<a:sibling1 .../>
<a:sibling2 attr2="value" />
<a:sibling3 .../>
Now, I need the value of the attribute "attr2" of the tag "sibling2" for all my tags - sibling1/2/3/etc - to work ... (once i get the value of attr2, I place it in the pageContext and hence there's no hassle following that - the problem is to get the value that first time) ... But I cannot assume where the sibling2 tag will be placed - it can be placed at first, at last, in-between, can be nested - u get my point ...
I was wondering if there was any way I could retrieve the tag handler instance for sibling2 from ANY tag on the page? ... or if u guys think there's a basic flaw in this design and can suggest an alternative ...
thanks ...

Take a look at the .java file that is parsed from the .jsp file; the tags will be processed in a top-down fashion as they appear in the .jsp page; by the time the doStartTag method of the second tag has been called, the doEndTag of the first tag will have completed, leaving the second tag no way to alter the output of the first tag.
If you want the functionality you describe then you'll have to place your tags into a common framework that will work around the top-down architecture of the page. Having a parent tag that collects its children, runs a check for shared data on each one, passes out any shared data it finds, then collects output from each, will allow you to do what you want.
If the whole point is to not have a parent tag, you may still be able to get the mess to work, but I don't know that it would be worth the effort.

ProviderContext get/setClientProperty problem with authlessanonymous

Hi all,
We have a Sun One Portal 6.2 where the desktop is the same for everyone. Its just a simple channel provided by a JSPSingleContainerProvider where one jsp will handle all the navigation.
The problem we have is related to authlessanonymous user for which we have to keep some properties values. From the documentation (ProviderContext class API), we have see that for anonymous user properties should be kept using get/setClientProperty.
So in our jsp, we retrieve the JSPProvider (using JSProvider object in pageContext) and then get the ProviderCXontext from it. The context object is used to call set/getPropertyClient.
But it seems that there's a twist with the context and his methods that we dont catch or this might be a bug. Still when the jsp is executed the call to setClientProperty dont seems to execute correctly every time.
Here's a sample jsp:
<%@page import="com.sun.portal.providers.jsp.JSPProvider
,com.sun.portal.providers.context.ProviderContext
,java.util.Date
%>
<%
// Objet SunOnePortal disponible uniquement en JSP, utilis� pour les variables de session
JSPProvider provider = (JSPProvider)pageContext.getAttribute("JSPProvider");
ProviderContext providerContext = provider.getProviderContext();
// debug
out.println(new Date(System.currentTimeMillis()).toString());
String nbstring = providerContext.getClientProperty("NB");
int nb=0;
if (nbstring != null) {
nb = Integer.valueOf(nbstring).intValue();
out.println("<br/>debut nb="+nb);
// Construction du path vers le Container et la page courante
String url_container = request.getContextPath()+request.getServletPath();
String url_courant = url_container+request.getPathInfo();
%>
<html>
<body>
<a href="<%=url_container%>/homel.html"><%=url_container%>/home.html</a>
<a href="<%=url_container%>/a_page.html"><%=url_container%>/a_page.html</a>
<a href="<%=url_container%>/about_us/about.htm"><%=url_container%>/about_us/about.htm</a>
<a href="<%=url_container%>/about_us/who_we_are/who.htm"><%=url_container%>/about_us/who_we_are/who.htm</a>
<a href="<%=url_container%>/another_path/another_page.html"><%=url_container%>/another_path/another_page.html</a>
<%
// Debug
nb=0;
nbstring = providerContext.getClientProperty("NB");
if (nbstring != null) {
nb = Integer.valueOf(nbstring).intValue();
out.println("<br/>fin nb ="+nb);
int xxx = nb + 1;
providerContext.setClientProperty("NB",String.valueOf(xxx));
out.println("<br/>apres set nb="+Integer.valueOf(providerContext.getClientProperty("NB")).intValue());
%>
</body>
</html>
In this we have a "NB" property that is a number we increase everytime the jsp is executed and the value is stored/retrieved using get/setClientProperty.
So when you click on the links on this page, the jsp is executed again and that should lead to increase of NB. The page is not complete, its just a sample to illustrate our problem. The goal is to force revisiting our jsp everytime.
But if you look at the link, the value is increased:
- For links where the static page (html) is directly a child of the /portal/dt URL, the value is increased everytime except the first time you click on the link???
- For links where the html page is in subfolder (that is not really a subfolder, i know) of /portal/dt (like /portal/dt/any_path/page.html), the value is increased only the first time we click on the link.
Also if you refresh/reload the page the value is increased everytime (that is correct).
Finaly, knows that this happens with anonymous user only, if you're login in that value is increased everytime you click a link!!!
We have defined the authlessanonymous user as described in the documentation. I also tried to add the authlessState property to the provider using the 3 allowed values: server, client, none.... This doesn't seems to have any effect at all.
PLEASE PLEASE! Can anyone can test this and confirm. Just define a new desktop with a single channel with JSPSingleContainerProvider, make the content a single jsp file and copy the code above in it. Then, make this desktop the default for authlessanonymous users. Then use a browser and click the links in the generated page....
What we need is simple, store string properties for the session for all users including anonymous. Since all anonymous share the same session, we have to use set/getClientProperty to store our value in the ProviderContext. That's what we do right now, but that does'nt seems to work as you see. So is there any other solutions?
Im sure we're not the only one to allows anonymous users in. And that you have some values to store for the session. So how are you doing this?
Any help/advices is welcome! We're really in deep s... because of this problem!
Dave Castonguay
[email protected]

Thx for the quick reply,
I tried both "Restart" and "Stop + Start" but still run into the problem when trying to connect Web Matrix unfortunately.
I can go through the trouble of deleting the site and creating it anew if worst come but I'm willing to try other ideas before that if you have any :)

How to find where an import item will come from for auto execute query?

I am trying to get a standalone stackLayout region to automatically execute the query on a VO when I run a test.
I found this thread, Re: Table creation and Data Population and tried adding the suggested code into my <companyname>.oracle.apps.fnd.framework.toolbox.server.<companyname>WorklistAMImpl. java, without the "if" clause wrapper.
if(pageContext.getParameter("Submit") != null)
OAApplicationModule am = pageContext.getApplicationModule(webBean);
OAViewObject vo = (OAViewObject)am.findViewObject("EmployeeVO1");
OATableBean table = (OATableBean)webBean.findChildRecursive("ResultTable");
table.queryData(pageContext, false);
However, when I try to compile, I get errors that the variable webBean, variable pageContext, and class OATableBean are not found in my class <companyname>.oracle.apps.fnd.framework.toolbox.server.<companyname>WorklistAMImpl. I had a couple others missing classes, which I figured out where they were and included them as imports.
My questions are:
1. Did I put this code in the right place?
2. How do I find out where the OATableBean exists (and generically, how do I find where a class exists, for future reference)?
3. In the case of the referenced note, how should I define the webBean and pageContext variables?
Thanks.
- Pam

I found where the OATableBean was defined, but I'd still like to know in general how to find classes. Is there a utility I can run that would list what's where?
Also, I figured out for the webBean and pageContext that I needed to import OAwebBean and OApageContext and then define the parameters in stream, so onw I'm successfully compiling; however, I still get "No search conducted" on the test rather than actually seeing the results of the VO. So, I sitll wonder if I have the code in the right place, or am I missing another piece? For instance, since my VO is based on a multi-org view, do I need to do something similar to set_client_info? Even if I did have to do that, I would expect a no data found rather than a no search conducted message.
The view code is as follows (note, I have commented out the bind variable for now and hard coded which distribution I want to find, so I expect it to get one row returned):
SELECT ReqDistributionsEO.DISTRIBUTION_ID,
ReqDistributionsEO.DISTRIBUTION_NUM,
ReqDistributionsEO.REQ_LINE_QUANTITY,
ReqDistributionsEO.REQ_LINE_AMOUNT,
ReqDistributionsEO.EXPENDITURE_TYPE,
ReqDistributionsEO.EXPENDITURE_ITEM_DATE
,prl.line_num
,pp.name project_name
,pt.task_number
     ,gcc.concatenated_segments
FROM PO_REQ_DISTRIBUTIONS ReqDistributionsEO
,po_requisition_lines prl
     ,pa_projects pp
     ,pa_tasks_v pt
     ,gl_code_combinations_kfv gcc
where ReqDistributionsEO.REQUISITION_LINE_ID = prl.REQUISITION_LINE_ID
and prl.requisition_header_id = 14247-- :1
and pp.project_id = ReqDistributionsEO.project_id
and pt.task_id = ReqDistributionsEO.task_id
and gcc.code_combination_id = ReqDistributionsEO.code_combination_id
Please help.

Putting own custom Writer class in the runtime enviornment of JSP

Hello All:
i have a doubt that i have made my own JSPWriter class and i want to use this class to be loaded in the runtime enviornment of the tomcat to get a custom output that is required by me .... for this i have written my own PageContext and through it i am instanciating this writer and successfully using it but is it the right procedure or i shall somehow need to follow some other procedure to get the task done. Another doubt that i have is if i load my suitable classes and in the runtime enviornment, will it effect the other applications that are running on the server ... and what ahould be the ways to overcome this .... is they follow the same procedure as i have then i think they are not supposed to face any problem ... kindly give me suggestions as i am in need of finding a solution as soon as possible ...
One another thing that i need to ask is that if we want to read the contents that are being sent to the client brower through the JSP then how to get that .....
I hope you will try to understand my urgency..
thanks in advance
Dodo

Please read http://java.sun.com/j2ee/tutorial/1_3-fcs/doc/Servlets8.html#82361 on filters and response wrappers. The advantage to this approach is that you can target your replacement writer to specific web resources and capture output.

PageContext and EL ?

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