dynamic filtering of resultlists

[binabik]

hi,

is there any way to dynamically filter a resultlist in a JSF view? i have a query that returns lectures which i'd like to display by semester (which is a column in the table). coming from ASP i know there's a method on the RecordSet object which lets you define a sql where-clause as a sublist criteria without a database round-trip.

is there anyway to do this with seam and jsf?

and if this is a stupid question, please tell me so -- my workaround at the moment would be to create multiple entityqueries for each sublist.

regards,
sb

[ellenzhao]

I would take this approach:

make a collection of lectures in the semester entity like this:

@Entity
@Name("semester")
...
public class Semester implements Serializable{
...

//I assume the semester and lecture is n:n so needing a linking entity called
// SemesterXLecture
private Set<SemesterXLecture> lectures;

@OneToMany // lazy or eager as you wish, I would prefer eager here
...
public Set<SemesterXLecture> getLectures(){
 return this.lectures;
}
}

Then, in one of your conversation beans, load all Semesters and cache them. Then, you can use

aSemester.getLectures();

anywhere in your conversation beans. You can also hood a semester in your xhtml file and use it similar to this code:

<h:dataTable value="#{someManager.semester.lectures}" var="lecture">
<h:column>
<h:outputText value="#{lecture.desc}" />
</h:column>
...
</h:dataTable>

so the lecture changes "dynamically" if you change the semester.


Regards,
Ellen

[ellenzhao]

sorry for my typos in the last post. I meant to cache all the semesters in a stateless bean, but not conversation bean.