Concatenate strings in JSF/JSP EL and Javascript

Question

I'm having troubles with EL and javascript functions (JSF 1.2, Facelets, Richfaces 3.3.0GA). I have a page that includes another composition:

<ui:include src="/pages/panels/examinationPanel.xhtml">
<ui:param name="prefix" value="new" />

And in my ui:composition I want to append the prefix to every id. For example:

<rich:modalPanel id="#{prefix}_examinationPanel">

That works ok.

But the problem comes when I want to access the components in functions suchs as oncomplete I cannot get it to concatenate the strings properly. For example

oncomplete="#{rich:component('#{prefix}_examinationPanel')}.show();"

I've tried with fn:join as well but it does not execute the function because it complains about errors when it finds "#" character. For example:

 oncomplete="#{rich:component(fn:join(#{prefix},'examinationPanel'))}.show()"

throws

SEVERE: Servlet.service() for servlet Faces Servlet threw exception org.apache.el.parser.ParseException: Encountered "fn:join( #" at line 1, column 33.

Encountered "fn:join( #"

Different errors if I brace it with brackets or with # and brackets.

What am I doing wrong?

And another question, in a conditional command like

oncomplete="#{a}?#{b}:#{c}"

How can I "group" to be able to execute more actions when true or false? Por example something like this:

oncomplete="#{a}?(#{b}#{f}):(#{c}#{d}#{e})"

I've tried with parenthesis but does not parse it properly.

Thanks in advance.

I'm using facelets. I edited the post to add that info, which indeed is relevant — pakore, Feb 03 '10 at 15:01

score 20 · Accepted Answer · edited Feb 03 '10 at 16:03

Assuming you are using Facelets, here's a relatively good solution:

create functions.taglib.xml in your WEB-INF

add a context param indicating the location:

<context-param>
    <param-name>facelets.LIBRARIES</param-name>
    <param-value>
        /WEB-INF/functions.taglib.xml
    </param-value>
</context-param>

In the xml put the following:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE facelet-taglib PUBLIC
  "-//Sun Microsystems, Inc.//DTD Facelet Taglib 1.0//EN"
  "https://facelets.dev.java.net/source/browse/*checkout*/facelets/src/etc/facelet-taglib_1_0.dtd">
<facelet-taglib xmlns="http://java.sun.com/JSF/Facelet">
    <namespace>http://yournamespace.com/fnc</namespace>
    <function>
        <function-name>concat</function-name>
        <function-class>com.yourpackage.utils.Functions</function-class>
        <function-signature>
            java.lang.String concat(java.lang.String, java.lang.String)
        </function-signature>
    </function>
</facelet-taglib>

in the page use the following:

xmlns:fnc="http://yournamespace.com/fnc"
....
oncomplete="#{rich:component(fnc:concat(prefix, '_examinationPanel'))}.show();"

finally, in the Function class define the simple method:

public static String concat(String string1, String string2) {
   return string1.concat(string2);
}

Thanks for the answer, I'm going to try it right now. One question, the trailing ";" for the param-value is intentional? And the other, isn't this the same as "fn:join" (which does not work) — pakore, Feb 03 '10 at 15:17
hm, no. I copied it from my configs, so it doesn't seem to do any harm either. — Bozho, Feb 03 '10 at 15:18
I've tried it and it works. And besides, I've learn a lesson about creating your own namespaces and functions :). Thanks for the fast and complete answer. — pakore, Feb 03 '10 at 15:44

score 15 · Answer 2 · answered Sep 09 '11 at 23:13

15

a simpler solution is to manage the String in the EL like an Object and use the method concat from the class String, something like this:

#{rich:component('constantString'.concat(variable))}.show();

answered Sep 09 '11 at 23:13

juanprq

151
1
4

4

Note that this only works in EL 2.2 or JBoss EL (for EL 2.1). OP didn't indicate that he's using Servlet 3.0 nor JBoss Seam. – BalusC Sep 09 '11 at 23:18
In that case he should consider adding EL 2.2 support, especially for the ability to pass parameters in function calls. – Christophe Roussy Apr 17 '12 at 09:07

Concatenate strings in JSF/JSP EL and Javascript

2 Answers2

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