Changing variable in JSF and passing it to bean

Question

hi, i want to list a table content(this is ok) and i want to create command links(Delete) for all rows so that users can delete rows that they want.For this i used a datatable.To delete a row, i have String deleteCountryByIndex() method in the bean.It should take a parameter from jsp page which is index of country which is wanted to be deleted.For this, i want to use a variable which i can increment it for each row.How can i do this?
public String deleteByIndex(){
FacesContext context = FacesContext.getCurrentInstance();
String paramValue = (String)
context.getExternalContext
().getRequestParameterMap().get("paramName");
... here i can take parameter from the page, but i cannot increment it on the page.
<h:dataTable id="dataC" var="tab" value="#{backingCountry.list}">
<h:column>
<h:outputText value="#{tab.country_id}" />
</h:column>
<h:column>
<h:outputText value="#{tab.country_name}" />
</h:column>
<h:column>
<h:outputText value="#{tab.region_id}" />
</h:column>
<h:column>
<h:commandLink value="sil" type="submit"
action="#{backingCountry.deleteByIndex}">
<f:param name="paramName" value="5"/>
</h:commandLink>
</h:column>
</h:dataTable>as you see, when i give the parameter 5, it deletes the fifth country.
how can i use a variable in the value property of f:param ?
Thanks for any advice.

Answer 1

That's not the way how to do it.
There are in general 3 ways to solve this problem.
1) Bind the h:dataTable to an UIData property in backing bean and use HtmlDataTable#getRowData() to get the row object where the link was clicked.
2) Use f:setPropertyActionListener instead of f:param, e.g. <f:setPropertyActionListener target="#{bean.tab}" value="#{tab}" />.
3) Move the action method from the backing bean to the row object itself, e.g. #{tab.delete}.
For more pointers and hints check this article: [http://balusc.blogspot.com/2006/06/using-datatables.html].