Using expressions in a custom tag
Does anyone see anything wrong with this code:
<table_disp:book_info
title="<%= temp_book.getTitle() %>"
author="<%= temp_book.getAuthor() %>"
isbn="<%= temp_book.getIsbn() %> />
The output puts the entire string "<%=...%> to the website. If I remove the double quotes, I get a compile error. If I put single quotes, the same result as double quotes occurs. How do I do this coorectly?
Thanks.
In your .tld file did you set the attributes to scriptable?
<attribute>
<name>messageOverride</name>
<required>false</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
Similar Messages
-
Problem in using jsp 1.1 custom tag library in websphere
I am using was 3.5.2. Everything has been installed properly. I am using jdeveloper 3.2 for building the jsp application using custom tag library. But when I run the jsp file in browser, its gives dr. watson on java.exe. I am using websphere 3.5.2 application server.
Have any body got this type of prob. ...
pls respond asap.
Thanks in Advance
YogeshLet me explain the problem again
I am using was(websphere) 3.5.2. Everything has been installed properly. I am using jdeveloper 3.2 for building the jsp application using custom tag library.
Application works fine in JDeveloper 3.2.
Application works fine even when deployed on JRun 3.0. ( we are evaluating various web servers).
How when deployed on WAS and I run the jsp file in browser, its gives dr. watson on java.exe. I am using websphere 3.5.2 application server.
WAS has typical settings as against JRun and Tomcat and may be I have not set the necessary paths.
Have any body got this type of prob. ...
pls respond asap.
Thanks in Advance
Yogesh
null -
EL expressions not evaluated in custom tag attribute
I'm writing a custom tag implementation where I need to have some attribute values
dynamically evaluated using EL, such that I can write:
<mytaglib:mytag id="${somevar}"/>
I cannot seem to accomplish this, however. My taglib tag definition looks like this:
<tag>
<name>mytag</name>
<tag-class>myclass</tag-class>
<body-content>empty</body-content>
<description>
Foo
</description>
<attribute>
<name>articleId</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
<type>java.lang.String</type>
</attribute>
</tag>
The implementation of myclass extends TagSupport (since I need to get at the PageContext). The setArticleId() method looks like this:
public void setArticleId(String idStr) throws JspException {
if (logger.isDebugEnabled()) {
logger.debug("idStr = " + idStr);
try {
/* XXX: Somehow, the evaluation should happen automagically, but
* I can't figure out why that doesn't happen!
String articleIdStr = (String)pageContext.getExpressionEvaluator().evaluate(
idStr,
java.lang.String.class, pageContext.getVariableResolver(), null);
this.articleId = Integer.parseInt(articleIdStr);
} catch (ELException e) {
throw new JspException("Failed to parse article id expression");
Why does it not work automagically?Make sure you are working with a JSP 2 container (like Tomcat 5). Also, you should make sure that your web.xml is configured to use the newest Servlet Spec. Read reply #6 on: http://forum.java.sun.com/thread.jspa?threadID=629437 to make sure it is set up properly.
If you are not using a JSP 2.0 container, then you will not be able to use EL in your custom tag. See: http://forum.java.sun.com/thread.jspa?forumID=45&threadID=725503 for alternatives. -
sir
plz tell me how to use custom tag in jsp.plz describe it.
i will be thankful to uDo you want to use taglibs or develop custom tags? Either way take a look at these:
http://java.sun.com/j2ee/tutorial/1_3-fcs/doc/JSPTags.html
http://www.stardeveloper.com/articles/display.html?article=2001081301&page=1
http://www.onjava.com/pub/a/onjava/2000/12/15/jsp_custom_tags.html
http://jakarta.apache.org/taglibs/tutorial.html
http://www.ibm.com/developerworks/edu/j-dw-java-custom-i.html
http://www.herongyang.com/jsp/tag.html -
Parsing EL expression in custom tag 10.1.3.4
Hello all,
I have a custom tag that extends CoreOutputTextTag. This tag needs to resolve the El expression passed in from the value attribute and perform an operation with it. Since I this tag needs to work with adf 10.1.3.4, the jsp level is 1.2 and does not support container parsing of EL expression directly in the page ($).
I have tried a couple approaches but both of them result in just the same EL expression I pass in being returned to me. Anyone have an idea of the proper way to resolve an EL expression within a custom tag?
Thanks in advance,
- Joe
public class CoreOutputTextTag extends oracle.adfinternal.view.faces.taglib.core.output.CoreOutputTextTag {
private String groupId;
private String groupCode;
private String value;
public void setValue(String value) {
this.value = value;
super.setValue(value);
public int doStartTag() throws JspException {
super.doStartTag();
UIComponent uiComponent = this.getComponentInstance();
if (uiComponent instanceof CoreOutputText) {
CoreOutputText coreOutputTextComponent =
(CoreOutputText)uiComponent;
if (coreOutputTextComponent.getValue() == null) {
String codeValue =
(String)ExpressionEvaluatorManager.evaluate("value", value,
java.lang.String.class,
this,
pageContext); // the page context
try {
ExpressionEvaluator expressionEvaluator =
pageContext.getExpressionEvaluator();
codeValue =
(String)expressionEvaluator.evaluate(value, java.lang.String.class,
pageContext.getVariableResolver(),
null);
} catch (ELException elex) {
SystemSettingRow row =
SystemSettings.getSystemSettings(groupId, groupCode, null,
value);
if (row != null)
coreOutputTextComponent.setValue(row.getShortDesc());
return TagSupport.SKIP_BODY;
public void setGroupId(String groupId) {
this.groupId = groupId;
public String getGroupId() {
return groupId;
public void setGroupCode(String groupCode) {
this.groupCode = groupCode;
public String getGroupCode() {
return groupCode;
<tag>
<name>coreOutputText</name>
<tag-class>od.adf.ics.ui.taglib.CoreOutputTextTag</tag-class>
<body-content>empty</body-content>
<attribute>
<name>groupId</name>
<required>true</required>
</attribute>
<attribute>
<name>groupCode</name>
<required>true</required>
</attribute>
<attribute>
<name>id</name>
<rtexprvalue>false</rtexprvalue>
</attribute>
<attribute>
<name>truncateAt</name>
<rtexprvalue>false</rtexprvalue>
</attribute>
<attribute>
<name>description</name>
<rtexprvalue>false</rtexprvalue>
</attribute>
<attribute>
<name>escape</name>
<rtexprvalue>false</rtexprvalue>
</attribute>
<attribute>
<name>shortDesc</name>
<rtexprvalue>false</rtexprvalue>
</attribute>
<attribute>
<name>partialTriggers</name>
<rtexprvalue>false</rtexprvalue>
</attribute>
<attribute>
<name>onclick</name>
<rtexprvalue>false</rtexprvalue>
</attribute>
<attribute>
<name>ondblclick</name>
<rtexprvalue>false</rtexprvalue>
</attribute>
<attribute>
<name>onmousedown</name>
<rtexprvalue>false</rtexprvalue>
</attribute>
<attribute>
<name>onmouseup</name>
<rtexprvalue>false</rtexprvalue>
</attribute>
<attribute>
<name>onmouseover</name>
<rtexprvalue>false</rtexprvalue>
</attribute>
<attribute>
<name>onmousemove</name>
<rtexprvalue>false</rtexprvalue>
</attribute>
<attribute>
<name>onmouseout</name>
<rtexprvalue>false</rtexprvalue>
</attribute>
<attribute>
<name>onkeypress</name>
<rtexprvalue>false</rtexprvalue>
</attribute>
<attribute>
<name>onkeydown</name>
<rtexprvalue>false</rtexprvalue>
</attribute>
<attribute>
<name>onkeyup</name>
<rtexprvalue>false</rtexprvalue>
</attribute>
<attribute>
<name>styleClass</name>
<rtexprvalue>false</rtexprvalue>
</attribute>
<attribute>
<name>inlineStyle</name>
<rtexprvalue>false</rtexprvalue>
</attribute>
<attribute>
<name>value</name>
<rtexprvalue>true</rtexprvalue>
</attribute>
<attribute>
<name>converter</name>
<rtexprvalue>false</rtexprvalue>
</attribute>
<attribute>
<name>rendered</name>
<rtexprvalue>false</rtexprvalue>
</attribute>
<attribute>
<name>binding</name>
<rtexprvalue>false</rtexprvalue>
</attribute>
<attribute>
<name>attributeChangeListener</name>
<rtexprvalue>false</rtexprvalue>
</attribute>
</tag>I also would like to know how to accomplish this. I have a similar requirement and need to set the "disable" attribute on a commandbutton and requires an el statement that calls a methodAction defined on the pageDef.
I followed the great instructions over on this thread:
ADF FACES:Creating custom component on top of adf
on how to create custom adf tags for JDeveloper 10.1.3.4.
many thanks!
Wes
Edited by: Wes Fang on Sep 16, 2010 5:39 AM -
How can i use JSTL inside custom tag attribute
Hi,
I have one button tag which displays the button with round corner. I will show the button like this:
<ep:button key="buttons.submit" name="submitBtn" styleClass="But"
onClick='submitPage(''<c:out value='${buttonName}' />)' />
I am getting the problem with the above code. how can i use JSTL inside the custom tags.
Thanks in Advance,
LALITHNo. The details are given below:
I have included the follwing line in web.xml file:
<taglib>
<taglib-uri>/tags/button</taglib-uri>
<taglib-location>/WEB-INF/button.tld</taglib-location>
</taglib>button.tld file
<taglib>
<tlibversion>1.0</tlibversion>
<jspversion>2.0</jspversion>
<shortname>button</shortname>
<tag>
<name>button</name>
<tagclass>com.ksi.ep.web.taglib.ButtonTag</tagclass>
<bodycontent>empty</bodycontent>
<attribute>
<name>name</name>
<required>true</required>
<rtexprvalue>false</rtexprvalue>
</attribute>
<attribute>
<name>key</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
<attribute>
<name>onClick</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
</taglib>ButtonTag.java :
public class ButtonTag extends TagSupport {
private static final long serialVersionUID = 6837146537426981407L;
* Initialise the logger for the class
protected final transient Log log = LogFactory.getLog(ButtonTag.class);
* holds the Value of the button tag
protected String onClick = null;
* holds message resources key
protected String key = null;
* The message resources for this package.
protected static MessageResources messages =
MessageResources.getMessageResources
("ApplicationResources");
* (non-Javadoc)
* @see javax.servlet.jsp.tagext.TagSupport#doStartTag()
public int doStartTag() throws JspException {
StringBuffer label = new StringBuffer();
HttpServletRequest request = (HttpServletRequest)pageContext.getRequest();
try {
log.debug("in doStartTag()");
Locale locale = pageContext.getRequest().getLocale();
if (locale == null) {
locale = Locale.getDefault();
log.info("");
label.append("<a border=\"0\" style=\"text-decoration:none;color:#FFFFFF\" href=\"JavaScript:");
label.append(onClick);
label.append("\" >");
label.append("<table onClick=\"");
label.append(onClick);
label.append("\" ");
if(onmouseout!=null && !"".equalsIgnoreCase(onmouseout))
label.append(" onmouseout=\"");
label.append(onmouseout);
label.append("\" ");
if(onmouseover!=null && !"".equalsIgnoreCase(onmouseover)){
label.append(" onmouseover=\"");
label.append(onmouseover);
label.append("\" ");
if(title!=null && !"".equalsIgnoreCase(title)){
label.append(" title=\"");
label.append(title);
label.append("\" ");
label.append("style=\"cursor:hand\" tabindex=\"1\" border=\"0\" cellpadding=\"0\" cellspacing=\"0\" background=\"");
label.append(request.getContextPath());
label.append(System.getProperty("file.separator"));
label.append("images");
label.append(System.getProperty("file.separator"));
label.append("background1.jpg\" > ");
label.append("<tr><td width=\"10\"><img border=\"0\" src=\"");
label.append(request.getContextPath());
label.append(System.getProperty("file.separator"));
label.append("images");
label.append(System.getProperty("file.separator"));
label.append("leftcorner.jpg\" ></td> ");
label.append("<td valign=\"middle\" style=\"padding-bottom:2px\"><font color=\"#FFFFFF\" style=\"");
label.append(styleClass);
label.append("\">");
label.append(messages.getMessage(key));
label.append("</font></td>");
label.append("<td width=\"10\" align=\"right\"><img src=\"");
label.append(request.getContextPath());
label.append(System.getProperty("file.separator"));
label.append("images");
label.append(System.getProperty("file.separator"));
label.append("rightcorner.jpg\" border=\"0\" ></td>");
label.append("</tr></table></a>");
pageContext.getOut().print(label.toString());
} catch (Exception e) {
log.error("Exception occured while rendering the button", e);
throw new JspException(e);
return (SKIP_BODY);
* Release all allocated resources.
public void release() {
this.name=null;
this.key=null;
this.onClick=null;
}In my JSP I have mentioned the taglib directive as
<%@ taglib uri="/tags/button" prefix="ep"%>and
<ep:button key="buttons.submit" name="submitBtn" styleClass="But"
onClick='overwritePreApprovals('<c:out value='${transactionalDetails['inPrepList']}' />')' />Servlet.service() for servlet action threw exception
org.apache.jasper.JasperException: /pages/pms/coordinator/Dashboard.jsp(325,48) Unterminated <ep:button tag
Thanks,
LALITH -
Hello, all. I am sadly failing to find a library function to escape HTML in Java. I'm writing a tag that used to use JSTL as a custom tag and don't know exactly where to find the functionality the JSTL is using. Consider the old JSP:
<c:forEach items="${versions}" var="version">
<tr>
<td><c:out value="${version.version}"/></td>
<td><c:out value="${version.releaseDate}"/></td>
</tr>
</c:forEach>and the new custom tag class:
public class VersionTableTag implements Tag
private PageContext context;
private Tag parent;
public int doEndTag() throws JspException
return EVAL_PAGE;
public int doStartTag() throws JspException
JspWriter out = context.getOut();
List versions;
try
versions = (List)(context.getVariableResolver().resolveVariable("versions"));
} catch (ELException e)
versions = new ArrayList();
try
out.println("<table>");
out.println("<tr>");
out.println("<th>Version</th>");
out.println("<th>Release Date</th>");
out.println("</tr>");
for (Object o : versions)
VersionVO version = (VersionVO)o;
out.println("<tr>");
out.println("<td>");
out.println(version.getVersion()); // NOTE: not properly escaped
out.println("</td><td>");
out.println(version.getReleaseDate().toString()); // NOTE: not properly escaped
out.println("</td>");
out.println("</tr>");
out.println("</table>");
} catch (IOException e)
throw new JspException(e);
return SKIP_BODY;
}My questions are as follows:
*1.* Is it possible to define a tag using a JSP document rather than a Java class? All I'm really after is something similar to an include but I want to be able to provide attributes to it in the long run.
*2.* Is there some library function I can use to escape the HTML in the VO above?1. Is it possible to define a tag using a JSP document rather than a Java class? All I'm really after is something similar to an include but I want to be able to provide attributes to it in the long run.Yes. It was introduced with JSP2.0: tag files.
Just like a JSP lets you write a servlet easily, a tag file lets your write a Custom tag class easily.
http://java.sun.com/javaee/5/docs/tutorial/doc/bnama.html
2. Is there some library function I can use to escape the HTML in the VO above?
There is one provided in the jakarta commons "lang" library.
http://commons.apache.org/lang/
They provide a class "StringEscapeUtils" which will do most of the common escaping that you require.
How hard is it to write something that replaces & < and > though? -
JSP Custom Tags, Tag Handlers, Passing values
Multiple questions here while I try to work with custom tags (its a requirement):
From what I have had so far - I have a .tld file, a .java file and a .jsp page.
(this is not a working version as I just got it from a website)
platform: tomcat on an xp box.
I was wondering if we can pass the parameters that are passed to the the jsp page (like blah.jsp?param1=value1¶m2=valu2 ) to the tag handler?
This is because the processing that I need to do in the handler would depend on what I have in the passed values.
Any help in letting me know where to place those files on the tomcat context root would help. Please see, I do have a couple of servlets running on the box also and they might be in the same context root.
Any good short tutorial link is also welcome as a short answer as I try to unravel the custom tags in jsp.I am using TomCat 5.5
What I need to do using tags is to build a web-page on the fly by polling a couple of different tables in the database.
This is to be done using a jsp and custom tag (requirement) which would be able to handle any resultsets. We also have to come up with pageContext attribute names and supply column names as those attributes. Thus we will have to come up with the meta data file and a tag library descriptor as well.
I found a helloworld solution on a website and was trying to modify it to meet my needs. But I guess I under-estimated the work that needed to be done in this one. -
JSP in custom tag attributes...
Sirs,
A very nice feature from a development perspective, would be the ability
to use JSP code within custom tags. Say I have a page on which I wish
to give all the information on a widget. Say further that I have
implemented a tag that writes out all the info of a widget as HTML
table. I would like to write something like this:
<mytaglib:widgetTag widgetID="<%=request.getParameter("widget_id")%>"
/>
As far as I know, in the current implementation of custom taglibs this
does not seem to be possible. Instead you end up writing something like
this:
<mytaglib:widgetTag>
<mytaglib:getWidget><%=request.getParameter("widget_id")%>"</mytaglib:getWidget>
<mytaglib:displayWidget />
</mytaglib:widgetTag>
Which is much more like a scripting language than a heirarchical XML .
Now, I could always just use the request object within the tag helper
classes, but this gives up flexibility and can introduce security
issues, and it also makes the tags much more difficult to work with...
In short, we should push for JSP evaluation of tag attributes. Weblogic
could leap ahead of other app servers in this area (making up for the
custom tag performance issues, to be solve in sp6) and Sun would, once
again, follow Weblogic's lead and rewrite the standard to include this
functionality.
Regards,
Carson Gross
Carson,
Perhaps the problem is that you are treating custom tags like one would
construct an imperative language. I have never had to put Java or use beans
or %= or even parameters to tags into a JSP because of custom tags.
The real problem is writing/packaging/maintaining all those tags; sure could
use a tool that did just that ;-)
Peace,
Cameron Purdy
[email protected]
http://www.tangosol.com
WebLogic Consulting Available
"Carson Gross" <[email protected]> wrote in message
news:[email protected]...
> Sirs,
>
> A very nice feature from a development perspective, would be the ability
> to use JSP code within custom tags. Say I have a page on which I wish
> to give all the information on a widget. Say further that I have
> implemented a tag that writes out all the info of a widget as HTML
> table. I would like to write something like this:
>
> <mytaglib:widgetTag widgetID="<%=request.getParameter("widget_id")%>"
> />
>
> As far as I know, in the current implementation of custom taglibs this
> does not seem to be possible. Instead you end up writing something like
> this:
>
> <mytaglib:widgetTag>
>
>
<mytaglib:getWidget><%=request.getParameter("widget_id")%>"</mytaglib:getWid
get>
>
> <mytaglib:displayWidget />
> </mytaglib:widgetTag>
>
> Which is much more like a scripting language than a heirarchical XML .
> Now, I could always just use the request object within the tag helper
> classes, but this gives up flexibility and can introduce security
> issues, and it also makes the tags much more difficult to work with...
>
> In short, we should push for JSP evaluation of tag attributes. Weblogic
> could leap ahead of other app servers in this area (making up for the
> custom tag performance issues, to be solve in sp6) and Sun would, once
> again, follow Weblogic's lead and rewrite the standard to include this
> functionality.
>
> Regards,
> Carson Gross
>
-
Hi
In CF8 it's not possible to use unc path for "Custom Tag
Paths"? In CF7 this
work! New feature? bug? possible workarounds?
Thanks,
AllanMark Mongeau wrote:
> I have serveral CF servers running. Is it possible to
map to custom tags on one
> server from another server without a share between the
servers?
> Or even with shared drives?
> What are the security issues if you create a share?
> Thanks
> Mark
>
It would be possible but both servers would have to be able
to read a
common network/file location. Either a shared drive on one CF
server or
the other or a common directory on a file server that both cf
servers
can read. For any of this to work one or both of the cf
servers will
have to be configured to run under a user (localsystem by
default on a
windows box) that has the required permissions to read the
desired
remote resource.
Once the required permissions are granted, one just needs to
put the
UNC/Mapped drive path to the shared custom tag directory in
the
appropriate server setting.
The risk is the same with granting any user permission to a
common file
location. They have the granted permissions to do what they
are allowed
to do at that location. With intelligent consideration of
what
permissions to give the user designated to run CF under this
can be
easily mitigated to a low risk issue. Don't use an
administrator/super
user account that can do anything anywhere. Create a CF user
and only
give it the required permissions to do what you need CF to
do. -
How can I use evaluate to get the instance variable in customized tag
1.
At first , I create a class called bean,and declared several params in it and do not define any getter function for the param.
class bean{
String param = "test";
SomeClass scObj = new SomeClass();
2.
The second ,I use
request.setAttribute("beanObj",new bean());
3.
And then I wanna use the customized tag to show a text box , then initialize it's value.
<salt:text name="param" value="beanObj.param">
<salt:text name="obj" value="beanObj.scObj.func()">
4.
I tried the evaluator provided by JexlContext ,Struts, JSTL and it seems that if I do not define the getter for the variable ,I can not get the bean's instance variable's value.
Expression e = ExpressionFactory.createExpression( value );
JexlContext jc = JexlHelper.createContext();
jc.getVars().put(strInitBeanName, request.getAttribute("beanObj"));
Object obj = e.evaluate(jc);
the result of the obj is null....
Can anybody recommand some other evaluator can get the value of a instance variable from an object?do you have any other suggestion ? Nops, somebody else may have though. AFAIK, all lookups of the type
beanName.propertyNameuse reflection on the getXXX() methods to access the property.
Having said that, I guess you could write one though in a custom tag, using the same - reflection (you will ahve to rely on the java.lang.reflect.Field class quite heavily) - but that would be reinventing the wheel for most other functionality that you would have to include (like looking up the bean in scope etc)
cheers,
ram. -
Custom Tag not evaluating expression in attribute
I have a custom tag that needs to take dynamic values in the attributes, but I can't seem to get the values "interpreted" correctly. I have the <rtexprvalue> tag set to "true" in my .tld file, which I thought was the only thing that was needed in order to accomplish what I am trying to do. However, that does not seem to be the case.
I am using WebLogic (8.1.4) and their <netui> tags, along with JSTL tags (1.0).
An example of what my code looks like is the following:
<test:myTag id="1" idx="<netui:content value='{container.index}' />">
<netui:select ... />
</test:myTag>and
<c:set var="myIdx" value="<netui:content value='{container.index}' />" />
<test:myTag id="1" idx="<c:out value='${myIdx}' />">
<netui:select ... />
</test:myTag>Neither of the above approaches has worked. In my code for my Tag.java file, I get the literal string values of <netui:content value='{container.index}' /> and <c:out value='${myIdx}' />, respectively, in my idx property.
Can someone give me any hints as to what I may be doing wrong?
Thanks.Shouldnt that be
<netui:content value='${container.index}' />Actually, weblogic does not use the '$' prefix before
their expressions. Fine. Which in turn means weblogic has some custom expression evaluator.
Note weblogic 8.1
as a container doesnt implicitly supportexpressions
and you have to build in that feature into yourtag
library.Are you referring to the 'isELIgnored' attribute when
you mentioned the above statement? If not, can you
explain what you meant by "build that feature into
your tag library"?
It's like this - expression language is supported by default in all containers that implement the j2ee 1.4 spec (servlet 2.4/jsp 2.0). Additionally you should also declare your web application to adhere to the 2.4 standards (through the schema definition in web.xml). In applications that refer to the 2.3 dtd but are run on a 2.4 compliant container you can set the 'isELIgnored' attribute to false and use EL. This works because your container anyways supports it.
If your container doesnt provide support for EL (outside the jstl tags) as is the case with weblogic 8.1, then you can still use expressions by using something like the [url http://jakarta.apache.org/commons/el/]apache common evaluator package. The difference being that you will have to call the evaluator classes to evaluate the attribute.
Are there any alternatives that I could use to
accomplish what I am trying to do?Did the above answer your question?
ram. -
Custom Tag using object as an attribute.
I have read up on trying to pass an object as an attribute to a custom tag.
Is it true that the only way to do this is to put the object, using a "key name" in the pageContext
Then in the custom tag, set an attribute equal to the "Key Name"
Then in the TagHandler, to do a lookup using the "Key Name"
We can not just past objects into the attribute?
And what is this about using EL or JSP2.0
sorry sort of new to the whole game.Certainly you can pass objects to tags.
However you need to use a runtime expression to do that.
such as <%= expr %> or (with JSP2.0) ${expr}
If you look at the JSTL library, it uses the EL and passes in objects all the time. However the EL actually accesses the page/request etc attributes as its variable space, so you are still technically using attributes.
Is it true that the only way to do this is to put the object, using a "key name" in the pageContext
then in the custom tag, set an attribute equal to the "Key Name"
then in the TagHandler, to do a lookup using the "Key Name"That is one way of doing it. The struts libraries use this method extensively. It is more suited to JSP1.2.
Sometimes it is easier/neater just to put the value into a scoped attribute, and pass in the name of that attribute. That way you don't need to worrry about the type of the attribute at all in your JSP.
Hope this helps some,
evnafets -
Custom tag attribute calculated by scriptlet expression
Hi,
If I set the rtexprvalue subelement of the attribute element in my tld to
"true", should I be able to dynamically determine the value of my custom tag
attribute using a scriptlet expression?
When I include the custom tag reference:
<prod:getCategory id="category"
categoryID="<%=request.getParameter("catID")%>" scope="page"/>
it actually gets written to the html as:
<prod:getCategory id="category" categoryID="2133" scope="page"/>
and is not recognized as a jsp tag.
I am using weblogic 6.0 sp1.
Thanks in advance!
daniel
I had the same problem in a design a couple of months ago and could not get around it so I switched the functionality into code and out of the tag lib.
I take it you are trying to do something like this?
<%
String value="hiworld";
%>
<mytaglib:saysomething value="<%=value%>"/> -
Using EL in custom tag with JSP1.2 container
I search the the Forum here and Google for a method how I can use expression language in my custom tag. But I have to use a JSP1.2 container which makes it quite difficult. What I need is startsWith-Tag which looks like this.
<str:startsWith condition1="${sql.rows[0].MY_COLUMN}" condition2="MyCondition">
</str:startsWith>Right now my tag works, but instead of the database of MY_COLUMN the string ${sql.rows[0].MY_COLUMN} is submitted.
In the TLD I specified rtexprvalue with true. My custom tag extends javax.servlet.jsp.jstl.core.ConditionalTagSupport.
What I read here was that I have to evaluate the el expression myself, but how do I do this? I hope someone can give me a hint how to make the tag working correctly.
TIA
AxelYou might find the source code of MicroNova YUZU (http://sourceforge.net/projects/micronova-yuzu) useful. It is an EL-based tag library that supports both JSP 1.2 and 2.0. See "jsp12" and "jsp20" subdirectories for version-specific EL handling. Hope this helps.
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