multiple calls to same method from <s:div rendered...>

[asookazian]

The getSeedSelection method in the SFSB named userRoleSearch is being exec'd six times when the following JSF is rendered. Why?

filterRoles.xhtml:

<!DOCTYPE composition PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">



<ui:composition xmlns="http://www.w3.org/1999/xhtml"
 xmlns:s="http://jboss.com/products/seam/taglib"
 xmlns:ui="http://java.sun.com/jsf/facelets"
 xmlns:f="http://java.sun.com/jsf/core"
 xmlns:h="http://java.sun.com/jsf/html"
 xmlns:c="http://java.sun.com/jstl/core"
 xmlns:rich="http://richfaces.ajax4jsf.org/rich"
 template="layout/template.xhtml">




<ui:define name="body">

 <h:messages globalOnly="true" styleClass="message"/>

 <rich:panel>
 <h:form>
 <h:panelGrid id="roles_grid" columns="1">
 <h1><h:outputText id="userRoleInfo" value="Filter by Role(s)"/></h1><br/>

 <h:selectBooleanCheckbox/>
 <b><h:outputText id="labelViewAll" value="View All"/></b>
 <br/><br/>

 <s:div rendered="#{userRoleSearch.seedSelection}">

 </h:panelGrid>
 </h:form>
 </rich:panel>

</ui:define>
</ui:composition>

[asookazian]

in SFSB:

public boolean getSeedSelection() {
 log.info("in seedSelection()");
 populate();
 return true;
 }

private void populate() {
 log.info("in populate()");

 try {
 con = DriverManager.getConnection(AdminConstants.URL, AdminConstants.USERNAME, AdminConstants.PASSWORD);
 cstmt = con.prepareCall("{call usp_u_adm_select_Role}");
 rs = cstmt.executeQuery();
 choices = new ArrayList<SelectItem>();
 while(rs.next()) {
 choices.add(new SelectItem(rs.getString("ApplicationRoleID"), rs.getString("Name")));

 String name = rs.getString("Name");
 log.info("populate(): name = " + name);
 String applicationRoleID = rs.getString("ApplicationRoleID");
 log.info("populate(): applicationRoleID = " + applicationRoleID);
 }
 alreadyPopulated = "a value indicating we are populated";
 }
 catch(Exception e) {
 e.printStackTrace();
 }
 finally {
 this.cleanUp();
 }

 //return allRolesHashMap;
 }

[asookazian]

only calls it once if getSeedSelection() returns false.

we're going to check for null on instance variables that are loaded (choices) to avoid DB round trips

[fhh]

Why don't you use:

a.) Datasources. Opening connections is an expensive operation.

b.) Use a SELECT statement instead of a call to a stored procedure if you want to retrieve data.

c.) @Factory for choices?

d.) Use entities and <s:selectitems> to create select items.

e.) Use Hibernate caching to avoid db roundtrips.

f.) Use Seam's query object to retrieve a filtered list of entities.

No offense, but if your requirements are totally different from the "Seam way of doing things" (TM) you will propably be better off without it.

Regards

Felix

[amitev]

And never in the jsf spec is told that your getter will be invoked only once per request

[asookazian]

thx for the feedback.

we are creating a Java version of existing C#/ASP.NET use cases using Seam. we are going to use the existing sprocs first and then convert them to pseudo-code/logic and use JPA entity beans from there.

[asookazian]

"amitev" wrote:
And never in the jsf spec is told that your getter will be invoked only once per request

why would they allow it to be called more than once? in case of network or db connectivity problems?

seems the user would just refresh their browser/screen...

[amitev]

It's not very good practice to put expensive logic in the getter/setter method

[saeediqbal1]

JSF backing bean methods/getters can be called unlimited times. there is no set limit. Ofcourse its not only one time because we have experienced 4-6 times ourselves. So live with it and maybe do what we did. put a condition statement to check if the property was already set. otherwise return whatever it had

[pmuir]

Use lazy initialization - @Factory does this for you.