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JSF Dropdown Perfomance Issues

 
Bansilal Haudakari
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Posts: 15
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I have a h:selectOneMenu dropdown which performs CRUD operation.
The dropdown list has a value "New" which allows the users to enter new values into other form fields thereby performing Create/Insert operation
When users pick other values from the dropdown list it dynamically populates other fields in the form thereby facilitating Update/Delete operation. The problem is whenever i pick a different value from the dropdown list the database call happens twice.

Here is the dropdown
Code:


<h:selectOneMenu id="manufList" value="#{manufacturerBean.selectedManufacturer}" >
<f:selectItem itemLabel="New" itemValue="New" />
<f:selectItems value="#{manufacturerBean.manufacturerList}" />
<a4j:support action="#{manufacturerBean.loadManufacturerDetails}" event="onchange" reRender="manufName,manufDescription,manufSource,btnSave,btnDelete" />
</h:selectOneMenu>
</h:panelGrid>




Here is the sequence of method calls whenever i pick a value from the dropdown list
- First time the method in f:selectItems gets called which results in a database call
<f:selectItems value="#{manufacturerBean.manufacturerList}" />
- Second time Ajax4JSF onchange event action method gets called .
<a4j:support action="#{manufacturerBean.loadManufacturerDetails}" event="onchange" reRender="manufName,manufDescription,manufSource,btnSave,btnDelete" />
- Third time again the method in f:selectItems gets called which results in a database call
<f:selectItems value="#{manufacturerBean.manufacturerList}" />

Here are my concerns
- Just picking a value from the dropdown shouldn't result in a call to database especially when there are no changes made to database

- I expect the calls to database happens ONLY in case of users click Save/Update/Delete buttons i.e. dropdown dynamically refreshes with database values

Here are the snippets from log file which substantiates that whenever i pick a value from dropdown
database call occurs twice
Code:

********** FIRST METHOD CALL ***************************
2007-05-07 16:46:46,002 INFO [com.boeing.nmt.nams.view.bean.ManufacturerBean] - < *** In getManufacturerList Backing Bean*** >
2007-05-07 16:46:46,002 INFO [com.boeing.nmt.nams.service.impl.ManufacturerManagerImpl] - < *** In getManufacturerList Spring*** >
Hibernate: select namsmanufa0_.ID as ID60_, namsmanufa0_.CHANGE_USER as CHANGE2_60_, namsmanufa0_.NA
ME as NAME60_, namsmanufa0_.DESCRIPTION as DESCRIPT4_60_, namsmanufa0_.SOURCE as SOURCE60_, namsmanu
fa0_.STATUS as STATUS60_, namsmanufa0_.CHANGE_DATE as CHANGE7_60_ from NAMS_MANUFACTURER namsmanufa0
_

********** SECOND METHOD CALL ***************************
2007-05-07 16:46:46,237 INFO [com.boeing.nmt.nams.view.bean.ManufacturerBean] - < *** In loadManufacturerDetails method *** >
Hibernate: select namsmanufa0_.ID as ID60_0_, namsmanufa0_.CHANGE_USER as CHANGE2_60_0_, namsmanufa0
_.NAME as NAME60_0_, namsmanufa0_.DESCRIPTION as DESCRIPT4_60_0_, namsmanufa0_.SOURCE as SOURCE60_0_
, namsmanufa0_.STATUS as STATUS60_0_, namsmanufa0_.CHANGE_DATE as CHANGE7_60_0_ from NAMS_MANUFACTUR
ER namsmanufa0_ where namsmanufa0_.ID=?

********** THIRD METHOD CALL ***************************
2007-05-07 16:46:46,565 INFO [com.boeing.nmt.nams.view.bean.ManufacturerBean] - < *** In getManufacturerList Backing Bean*** >
2007-05-07 16:46:46,565 INFO [com.boeing.nmt.nams.service.impl.ManufacturerManagerImpl] - < *** In getManufacturerList Spring*** >
Hibernate: select namsmanufa0_.ID as ID60_, namsmanufa0_.CHANGE_USER as CHANGE2_60_, namsmanufa0_.NA
ME as NAME60_, namsmanufa0_.DESCRIPTION as DESCRIPT4_60_, namsmanufa0_.SOURCE as SOURCE60_, namsmanu
fa0_.STATUS as STATUS60_, namsmanufa0_.CHANGE_DATE as CHANGE7_60_ from NAMS_MANUFACTURER namsmanufa0
_



I do have Managed Bean in Session scope

Regards
Bansi
 
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