Custom "usebean" tag.

I've a problem trying to register a variable into my jsp.
Normal method to auto-fill a bean looks like :
<jsp:useBean id="mybean" scope="page" class="mybeanclass" />
<jsp:setProperty name="mybean" property="*" />
<%
// I can use my bean here
mybean.mymethod();
// do something
%>
Now, i can't auto-fill my bean, because i've specific parameters. Then i write a custom tag that correctly fills the bean, but i don't know how can i register the variable so i can't use it later in code.
<mytaglib:load id="mybean" scope="page" />
<%
// only works with one class type.
// Scope ? how can i register my variable in various scopes ?
// can i use my bean here ? how ?
mybean.mymethod(); // crash!!!
%>

Now, i can't auto-fill my bean, because i've specific
parameters. Then i write a custom tag that correctly
fills the bean, but i don't know how can i register
the variable so i can't use it later in code.
<mytaglib:load id="mybean" scope="page" />
<%
// only works with one class type.
// Scope ? how can i register my variable in various
scopes ?
// can i use my bean here ? how ?
mybean.mymethod(); // crash!!!
%> The simplest answer is to use the <jsp:useBean> to create the scripting variable and instantiate the bean, and then use the tag to populate the bean.
<jsp:useBean id="mybean" scope="page" class="mybeanclass" />
<mytaglib:load id="mybean" />The load tag could reference the bean as a PageContext attribute using the key specified in the id attribute ("mybean" in this case).
If you don't want to use useBean, change the tld definition for the load tag to define a scripting variable. The <tag> definition would look something like:
<tag>
        <name>load</name>
        <tag-class>yourpackage.LoadTag</tag-class>
        <body-content>JSP</body-content>
        <variable>
            <name-from-attribute>id</name-from-attribute>
            <variable-class>yourpackage.mybeanclass</variable-class>
            <declare>true</declare>
            <scope>AT_END</scope>
        </variable>
        <attribute>
            <name>id</name>
            <required>true</required>
            <rtexprvalue>false</rtexprvalue>
            <type>String</type>
        </attribute>
    </tag> In the tag, instantiate the bean and add it a page attribute using the value of id as the key. The JSP engine should generate a scripting variable of the same name.

Similar Messages

How to use "scope " attrubute in useBean tag

Can anyone please tell me if I can use the same JavaBean Class to hold information form different pages? well, let me explain exactely what I want to do:
I have a Java bean Class that holds a property 'Name':
package ContactManager;
public class Person {
private String name="%";
public String getName () {
return this.name;
public void setName (String my_name) {
name = my_name + "%" ;
I'm using this class to store temporarly the Criteria of search from a JSP/HTML page to send to a database for search and for UPDATE -> this of course is done in different HTML/JSP pages. The problem I have is that the first time I set the properties (when the user make a search) this value remains unchanged [-> the second time when the user asks for update, I try to use the same bean to keep the value => unfortuntly it returns me the old value]
My question is: is the use of 'scope' attribute of the "jsp:useBean" tag can solve this problem? if yes how to use it? I've tryed to set the scope of the bean to page but that does not help :-(
Pleaze help, I'm stuck.... Bellow is the 4 JSP pages for:
- person_search.jsp / person_result.jsp
- request_modify.jsp/ DoModify.jsp
1 -person_search.jsp
<%@ page import="java.sql.*" %>
<HTML>
<HEAD><TITLE>Person Search</TITLE></HEAD>
<BODY><CENTER>
<form method="POST" action="person_result.jsp">
Name <input type="text" name="name" size="47"></p>
<input type="submit" value="Submit" name="B1">
<input type="reset" value="Reset" name="B2"></p>
</form></body>
</html>
2- person_result.jsp
<%@ page import="java.sql.*" %>
<HTML><BODY>
<jsp:useBean id="theBean" class="ContactManager.Person"/>
<jsp:setProperty name="theBean" property="*" />
Name<BR>
<%
try {
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
System.out.println("JDBC driver loaded");
catch (ClassNotFoundException e) {
System.out.println(e.toString());
%>
<%
try {
Connection con = DriverManager.getConnection("jdbc:odbc:ContactManager");
Statement s = con.createStatement();
String sql = "SELECT Client.ClientID, Client.Name FROM Client where Client.Name like " + "'" + theBean.getName() + "'";
ResultSet rs = s.executeQuery(sql);
while (rs.next()) {
String myId = rs.getString(1);
%>
<TR>
<TD><%= myId %></TD>
<TD><a href="person_detail.jsp?id=<%= myId %>"><%=rs.getString(2)%></a></TD>
<TD><a href="delete_person.jsp?id=<%= myId %>">Delete</a></TD><BR>
</TR>
<%
rs.close();
s.close();
con.close();
catch (SQLException e) {
System.out.println(e.toString());
catch (Exception e) {
System.out.println(e.toString());
%>
</BODY>
</HTML>
3- request_modify.jsp
<%@ page import="java.sql.*" %>
<html>
<head><title>AddressBook: Modifying Person <%= request.getParameter ("id") %></title> </head>
<body bgcolor="#ffffee">
<%
try {
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
System.out.println("JDBC driver loaded");
catch (ClassNotFoundException e) {
System.out.println(e.toString());
%>
<%
int rowsAffected = 0;
try {
Connection con = DriverManager.getConnection("jdbc:odbc:ContactManager");
Statement s = con.createStatement();
String sql = "SELECT Client.ClientID, Client.Name FROM Client where ClientID ="+ request.getParameter("id");
ResultSet rs = s.executeQuery(sql);
if (rs.next()) {
%>
Client Name is <input type=text name=name value=<%= rs.getString(2) %>> <br>
<TD><a href="person_do_modify.jsp?id=<%= rs.getString(1)%>">Confirm Modify</a></TD>
<%
rs.close();
s.close();
con.close();
catch (SQLException e) {
System.out.println(e.toString());
catch (Exception e) {
System.out.println(e.toString());
%>
</BODY> </HTML>
4- do_modify.jsp
<%@ page import="java.sql.*" %>
<html>
<head><title>AddressBook: Modifying Address <%= request.getParameter ("id") %></title></head>
<body bgcolor="#ffffee">
<jsp:useBean id="theBean" class="ContactManager.Person" scope="page"/>
<jsp:setProperty name="theBean" property="name"/>
<%
try {
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
System.out.println("JDBC driver loaded");
catch (ClassNotFoundException e) {
System.out.println(e.toString());
%>
<%
int rowsAffected = 0;
try {
Connection con = DriverManager.getConnection("jdbc:odbc:ContactManager");
PreparedStatement preparedStatement = con.prepareStatement ("UPDATE Client SET Name=? WHERE ClientID =?");
preparedStatement.setString (1, theBean.getName());
preparedStatement.setString (2, request.getParameter("id"));
rowsAffected = preparedStatement.executeUpdate ();
preparedStatement.close ();
if (rowsAffected == 1) {
%>
done
<%
else{
%>
Not Modified
<%
con.close();
catch (SQLException e) {
System.out.println(e.toString());
catch (Exception e) {
%>
</BODY></HTML>
Thank you for the help.
Sammy

While a quick search on the <jsp:useBean> tag and the scope attribute will probably yield more information than I can summarize in a few sentences, I'm pretty sure that using the scope="page" attribute on a bean will cause that bean to be instantiated every time the page is loaded. In order for a bean to persist longer than the existance of that page (whether you're loading a new page, or reloading the same one), you'd need to set the scope to session or application (you'd probably want session).

How to use custom defined tags in uix in jdevloper 10g production

can any one give me sample application for how to work with custom defined tags in uix with jedevloper 10g production
thanks Venkat

Hi Venkat,
Maybe the reason for no one answering is because of lack of information in your post? What are you trying to do? Are you using JSP or UIX XML? Have you checked the online jdeveloper documentation? Have you checked the doc available in the JDeveloper release? Before we have more information we can't help you. Sorry
Thanks,
Jonas
JDev Team

Problems in developing custom JSP tags

I have problems in debugging custom JSP tags. Sometimes the doStartTag is not called on tags but the doEndTag is called. I don't know why.
Thanks.

Fahr--
A word of caution -- NetUI did not ship a JSP tag SDK in 8.x, and
we're making no compatibility guarantees for custom JSP tags written on
the 8.x release and future releases.
You can accomplish the same sort of functionality with a combination
of the <netui-data:getData> tag and JSTL 1.0. This solution would
probably provide similar functionality and be more future-proof relative
to JSTL and the NetUI tags currently being developed in Beehive.
Hope that helps.
Eddie
Fahr Vegnugen wrote:
We are in the midst of creating our own JSP tags to work with datasources.
In an example where you would need to compare two different datasources how would you do this?
ie.
<prefix:isGreater dataSource="{pageflow.column1}" dataSourceToCompare="{pageFlow.column2}" />
How would I evaluate what column2 is since the tag will only resolve one data source
this.evaluateDataSource();
Any pointers you can provide would be appreciated, or if there is a library of jsp tags that evaluate objects using datasources already created, that would even be better.

JSF 2.0 Custom security tag

We are migrating a JSF 1.2 application to JSF 2.0. Earlier we have developed a custom security by extending BodyTagSupport. In JSF 2.0 I have replaced BodyTagSupport with TagSupport and no compilation issues. In my taglib.xml if I configure this Tag with a handler-class[Which is how it was earlier] While running I am getting a class cast exception of not able to cast to TagHandler and If I configure this tag as component[I extended UIComponentELTag] I am getting error message as not able to cast to UIComponent.
Has any one developed a custom security tag, for examle check user role and if allowed dynamically display set of buttons or skip the particualr body part completely. By doStartTag()[EVAL_BODY_INCLUDE/SKIP_BODY]?
Edited by: user11864278 on Apr 14, 2011 1:07 PM

We are not extending TagHandler, I am trying to develop a custom EL Body tag that was earlier done with BodyTagSupport in JSF 1.2. In JSF 2.0 I believe I need to do this by extedning FacetTag in JSF 2.0, when I extend FacetTag and register it as a <handler-class> in taglib.xml I get a TagHandler class cast exception, as by default any Tag configured as Handler-class get cast into TAGHANDLER in JSF 2.0.
To make my question better, How can I develop a custom tag extending FacetTag?

Custom JSP Tags for Weblogic

Hi,
          I have several questions regarding this topic:
          1) Does Weblogic 5.1 supports Custom Tags ? If so, are there any known
          problems ?
          2) Does Weblogic come with any tag libraries (for loops, if, etc) and where
          can I get them ?
          3) Are there any tag libraries out there (JRun, for example) that have been
          successfully run on Weblogic ?
          Any help would be much appreciated.
          Thanks,
          Jamie


As there seems to be general interest, a link would probably be a great
          help.
          Regards
          Daniel Hoppe
          -----Original Message-----
          From: Michael Girdley [mailto:[email protected]]
          Posted At: Friday, August 25, 2000 8:03 AM
          Posted To: jsp
          Conversation: Custom JSP Tags for Weblogic
          Subject: Re: Custom JSP Tags for Weblogic
          Please see the documentation:
          http://www.weblogic.com/docs51/resources.html
          Michael Girdley
          BEA Systems Inc
          "Jamie" <[email protected]> wrote in message
          news:[email protected]...
          > Update
          > =======
          >
          > Weblogic Portal has some Tag libraries. I've downloaded the trial
          version
          > of
          > the Weblogic Commerce Server. How do I get the tag libraries and use
          them
          > on WL 5.1 ?
          >
          > Answers to original post still wanted
          >
          > Thanks,
          >
          > Jamie
          >
          > Jamie <[email protected]> wrote in message
          > news:[email protected]...
          > > Hi,
          > >
          > > I have several questions regarding this topic:
          > >
          > > 1) Does Weblogic 5.1 supports Custom Tags ? If so, are there any
          known
          > > problems ?
          > >
          > > 2) Does Weblogic come with any tag libraries (for loops, if, etc)
          and
          > where
          > > can I get them ?
          > >
          > > 3) Are there any tag libraries out there (JRun, for example) that
          have
          > been
          > > successfully run on Weblogic ?
          > >
          > >
          > > Any help would be much appreciated.
          > >
          > > Thanks,
          > >
          > > Jamie
          > >
          > >
          >
          >

Using variables in a jsp:useBean tag

I was wondeing if it is possible in any way to use variables in a jsp:useBean tag. Here is an example of what I am trying to do.
<%
String beanType = request.getParameter( "bean" );
if( beanType.equals( "Bean1" ) ) {
beanClass = "com.myCompany.Bean1";
} else {
beanClass = "com.myCompany.Bean2";
%>
<jsp:useBean name="<%= beanType %>" class="<%= beanClass %>"/>
I also tried using this approach
<%
if( beanType.equals( "Bean1" ) ) {
%>
<jsp:useBean id="bean" class="com.myCompany.Bean1"/>
<%
} else if( beanType.equals( "Bean2" ) ) {
%>
<jsp:useBean id="bean" class="com.myCompany.Bean2"/>
<%
%>
Neither approach seems to work. Is there any way around this problem?
Thanks,
Marcus.

Hi,
check:
http://forum.java.sun.com/thread.jsp?forum=45&thread=398998&tstart=75&trange=15

How can i load A gui JTable bean through jsp:useBean tag in a jsp page

Hi,
i am chiranjit , i am in a jsp project . i am desparately looking a solution for below stated problem:
i want to make a jsp page for master entry , that why i want to load a GUI Java bean in my jsp page.This GUI Bean contaning a JTable in which allow grid type data entry in the jsp page. But i am unable load that bean in the jsp page through jsp:useBean tag in my page.So if you have any solution then send in the forum as early as possible.
Thank you
chiranjit

No can do. JSPs can only output plain HTML (and javascript...) They are not used like normal Java classes.
If you need a complex GUI then you might use an Applet instead. If you want to use a JSP then you are stuck using normal HTML components, like <table> <form...> <input type="text"> etc...

Calling an inner class in a jsp:usebean tag

Hi everybody !
Here's my problem : working in my project on multiple pages, I'm using inner classes/beans to limitate my '.java' files but I'm stuck when calling that 'inner-bean' in my jsp:usebean tag.
First, I tried to declare in the class parameter : 'class="MyPrincipalBean.theInnerBean" but jsp returns me a 'not found' message.
I tried an other issue with this :
'class="MyPrincipalBean$theInnerBean" but I encountered a 'Attempt to use a bean type without a void constructor in jsp:useBean tag (JSP 1.1 specification, 2.13.1)'. Since I can't find that specification, I'm sending an SOS.
Am I on the good way ? If somebody as encoutered that sort of problem, it would be very kind of you to help me.
Thanks for your help !
[email protected]

Thanks for your help!
I must recognize that my explainations weren't really precise.
My principal bean owns a table of my inner-class type :
public class FirstBean extends EntityBean {
private SecondBean[] tabSB;
public SecondBean[] getTabSB() {...}
public void setTabSB(SecondBean[] p_tabSB) {...}
public class SecondBean {...}
So I can call a specific bean from the tab in my Servlet for another page.
But I think I have the solution and I need your advise :
I tried this :
<jsp:useBean id="FirstBean" class="<...>.FirstBean" scope="session" />
<jsp:useBean id="SecBean" beanName="<...>.FirstBean$SecondBean" type="<...>.FirstBean$SecondBean" scope="request" />
And would you believe it ? It seems to work ! But I have to test this farther to be sure. What do you think of it ?

Hi, I have quick question about use of USEBEAN tag in SP2. When I specify a scope of SESSION for the java bean, it does not keep the values that I set for variable in the bean persistent.Thanks,Sonny

Make sure that your bean is implementing the serializable interface and that
you are accessing the bean from the session with the same name.
Bryan
"Sandeep Suri" <[email protected]> wrote in message
news:[email protected]..
Hi, I have quick question about use of USEBEAN tag in SP2. When I
specify a scope of SESSION for the java bean, it does not keep the
values that I set for variable in the bean persistent.Thanks,Sonny
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WL5.1: Using JSPC with pages that include usebean tags

Hi All,
          I'm trying to get JSPC to correctly compile my JSP pages (which compile with
          no problems from within Weblogic itself) and for each page that contains a
          <userbean> tag, it seems as though java is trying to instantiate the bean as
          it turns the JSP page into a servlet.
          I can stop this happening by changing the <usebean class="foobar"/> tag to a
          <usebean type="foobar"/>, but according to the documentation, this technique
          is only supposed to be used when the bean's object is expected to be in
          scope already, which is not the case.
          Is there anyway to tell JSPC not to instantiate the beans in the <usebean>
          tags?
          bye


Hi All,
          I'm trying to get JSPC to correctly compile my JSP pages (which compile with
          no problems from within Weblogic itself) and for each page that contains a
          <userbean> tag, it seems as though java is trying to instantiate the bean as
          it turns the JSP page into a servlet.
          I can stop this happening by changing the <usebean class="foobar"/> tag to a
          <usebean type="foobar"/>, but according to the documentation, this technique
          is only supposed to be used when the bean's object is expected to be in
          scope already, which is not the case.
          Is there anyway to tell JSPC not to instantiate the beans in the <usebean>
          tags?
          bye

Custom metadata tags?

I know that by tweaking the flex config files you can have
custom metadata tags and you can extract them with reflection (
describeType() )
But can this happen in flash?
Can they be substituted by a clever use of interface or
inheritance?

File a bug with a simple test case if there already isn't one. No
guarantees it will get fixed? Why can't you put the metadata on the class?

How to render custom JSP tags

We have our own custom JSP tag libraries (some of them extend the Struts tags, but many do not) and want those to render correctly in the design view.
Is that supported by NitroX Struts, or will it only work with built-in Struts tags?
If it is supported, how does one get NitroX to run the custom tags?

It is possible to customize many aspects of the rendering of a custom tag. This is done using a combination of an M7 specific metadata, and standard css rules.
For example, you can change the label, icon and border of a custom tag by doing the following steps:
1) Create a folder named "nitrox" where your tld file is located. For example if you have "/WEB-INF/app.tld" then create a
folder "/WEB-INF/nitrox/".
2) In the nitrox folder created above, create a file named "app.tlei" (for Tag Library Extra Information). The file name used here should match the name of the tld file. In this case "app".
3) Paste the following content in the app.tlei file:
<taglib-extrainfo>
<css-uri>app.css</css-uri> 
<tag name="myTag">
<display-name>My Tag</display-name> 
<rendering-label>{tag-name} ({name})</rendering-label> 
<small-icon>images/myTag.gif</small-icon> 
</tag>
</taglib-extrainfo>
All customization tags are optional.
4) Create the css file referenced from the tlei file above (in this example app.css in the same directory containing the tlei file).
5) Paste the following content in the app.css file:
myTag {border: 1 solid red; display: "inline"}
This will render the tag as inline (i.e as one graphical object) even if the tag has nested content.
In addition, you can use any standard css style property.
You can customize other tags in the same fashion.
If a custom tag inherits from a Struts tag, then the tag can inherit the full built-in tag customization as shown in the following example:
Suppose you have a tag named "myText" that extends the Struts html:text form field tag. To inherit the NitroX html:text customization you follow the steps:
1) insert the following in the tlei file described above:
<tag name="myText">
<inherit taglib-uid="http://jakarta.apache.org/struts/tags-html" tag-name="text" />
</tag>
2) Insert the following css rule in the css file referenced from the tlei file:
myText {m7-inherit: "input-text"; display: inline}
This will inherit the built-in css style for form text fields.
Likewise, you can inherit the other Struts tags css styles by using the following rules:
myPassword {m7-inherit: "input-password"; display: inline}
myCancel {m7-inherit: "input-submit"; display: inline}
myCheckbox {m7-inherit: "input-checkbox"; display: inline}
myRadio {m7-inherit: "input-radio"; display: inline}
mySelect {m7-inherit: "select"; display: inline}
myTextarea {m7-inherit: "textarea"; display: inline}
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M7 Support

Unable to use jsp:useBean tag

when I use
<jsp:useBean id="addressBean" class="AddressBean" scope="session"/>
I get the following error
Exception Details: org.apache.jasper.JasperException
Unable to compile class for JSP No Java compiler was found to compile the generated source for the JSP. This can usually be solved by copying manually $JAVA_HOME/lib/tools.jar from the JDK to the common/lib directory of the Tomcat server, followed by a Tomcat restart. If using an alternate Java compiler, please check its installation and access path.
So my question is how to use the <jsp:useBean> tag in JSC

Please see my message How to set developer's mode for oracle jsp engine.
As a very early warning of the future, this way of setting configuration paramemter in web.xml for oracle jsp engine will be deprecated in the next major version of oc4j and desupported probably later on. Yes, it is still supported in 10.1.3 and the next major version, though.

Usebean Tag

What are the advantages of usebean tags in jsp.
Is there any benefits, if i'm not using any SQl queries in JSP.
If i used Javabeans set & get methods and store them in a vector, in a web application. How far it will increase the performaance?

Its not a question of performance.
Its a question of design and maintainability.
Pages with lots of java scriptlet code mixed in with HTML are difficult to read and understand, and harder to maintain than JSPs with no scriptlet code.
The same reason for not including sql code in your JSP.
The aim is to have the SQL code in ONE place, so if it changes, then you only have to change it in one place.
If you have bits of SQL scattered through 5-6 jsp pages it becomes that much more difficult.

Custom "usebean" tag.

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