"for" cycle in JSF

Question

I simply need to perform a very basic for cycle in JSF/ICEFaces, basically rendering column numbers

Something like the following pseudo-code

for(int i=0; i<max; i++)
{
   <td>#{i}</td>
}

the <c:forEach> tag iterates over collections, but I don't want to make my backing bean more complex returning a stupid collection of integers.

Do you know a shorter and smarter way?

Thank you

JSTL's `c:forEach` is okay for simple stuff like this. However, due to the rendering nature of it, you can easily get into [trouble](http://stackoverflow.com/a/4154930/1009867). I recommend using `ui:repeat` instead. — geca, Dec 02 '11 at 10:24
I second @geca's reply. `` takes a collection as a value and iterates over each element, inside you can write any markup you want. — arg20, Mar 12 '12 at 13:47

score 11 · Answer 1 · answered Mar 10 '11 at 10:06

11

<c:forEach var="i" begin="1" end="#{someBean.max}">
             <td>#{i}</td>      
 </c:forEach>

answered Mar 10 '11 at 10:06

jmj

237,923
42
401
438

Yea definitely correct ;);) I thought the items property was required, I just tried the code and worked fine :D :D – usr-local-ΕΨΗΕΛΩΝ Mar 10 '11 at 10:06

score 5 · Accepted Answer · answered May 14 '12 at 14:51

The <ui:repeat> tag is what you should really use. The JSTL tags operate outside of the JSF Lifecycle. Cay Horstman has a JSF coursewhich discusses this fact: ui:repeat and Handling Variable-Length Data.

There are a couple of solutions below which demonstrate some flexibility. You could do something like this:

<ui:param name="max" value="5"/>
<ui:repeat var="i" value="#{indexBean.values}" size="#{max}" >
 <tr><td>#{i}</td></tr>
</ui:repeat>

The maximum number of rows is determined by a a <ui:parameter> named max. This is not required, but does demonstrate flexibility. Alternatively you could use something like:

<ui:param name="max" value="5"/>
<ui:repeat var="i" value="#{indexBean.rowNumbers(max)}">
 <tr><td>#{i}</td></tr>
</ui:repeat>

The backing bean code is the following:

@ManagedBean
public class IndexBean {

public List<Integer> getValues() {
    List<Integer> values = new ArrayList<Integer>();
    for (int i = 0; i < 10; i++) {
        values.add(i);
    }
    return values;
}

public List<Integer> rowNumbers(final int max) {
    List<Integer> values = new ArrayList<Integer>();
    for (int i = 0; i < max; i++) {
        values.add(i);
    }
    return values;
}
}

Please note I have opened a bug [JAVASERVERFACES-2425](http://java.net/jira/browse/JAVASERVERFACES-2425) on the size attribute. The size VDL document does not indicate that the value includes the end element for example `size=5` prints out 0-5 instead of 0-4 which would be five elements. I expect this will be corrected in 2.2. — John Yeary, May 24 '12 at 22:40

score 4 · Answer 3 · answered Mar 10 '11 at 10:07

4

I suggest thinking at a higher level of abstraction, not in terms of rendering HTML tags, but in terms of using a component that does what you need. For example, Primefaces' datatable supports dynamic columns, which should be capable of replacing your on-page iteration logic.

answered Mar 10 '11 at 10:07

Michael Borgwardt

342,105
78
482
720

Surely a wise answer, but what I need to do in my case is really too simple to think about a smarter design. Anyway thanks and upvote! – usr-local-ΕΨΗΕΛΩΝ Mar 10 '11 at 10:24

score 1 · Answer 4 · answered Sep 12 '17 at 21:52

1

Simple example using ui repeat

<ul>
    <ui:repeat var="entry" value="${tourBean.tour.highlights}">
        <li class="pb-1">#{entry}</li>
    </ui:repeat>
</ul>

answered Sep 12 '17 at 21:52

Mircea Stanciu

3,675
3
34
37

score -1 · Answer 5 · edited Oct 01 '11 at 18:09

-1

with rich faces data table you can dynamically generate columns headers and values

edited Oct 01 '11 at 18:09

Cédric Julien

78,516
15
127
132

answered Oct 01 '11 at 10:54

Armen

34
1

"for" cycle in JSF

5 Answers5

Linked