How to display variable number of columns in primefaces datatable - jsf

Question

I have the following ArrayList
class Report{
private String manufacturer;
private String color;
private List<Double> revenue;
}
How can I display it on primefaces datatable. I tried using p:columns it is not working.
I have following code on XHTML page
<p:dataTable value="#{tableBean.reportList}" var="report" id="table">
<p:column headerText="Manufacturer">#{report.manufacturer}</p:column>
<p:column headerText="Color">#{report.color}</p:column>
</p:dataTable >
I also tried p:columns and ui:repeat. But I am not able to achieve desired output. result.
<p:columns var="amount" value="#{report.revenue}">#{amount}</p:columns>
<ui:repeat var="amount" value="#{report.revenue}">
<p:column headerText="Revenue">#{amount}</p:column>
</ui:repeat>
I need output as a table with manufacturer name, color and all revenues

Answer 1

Your mistake is that you referenced the currently iterated row (the object behind <p:dataTable var> as <p:columns value>. This is not possible. The amount of columns cannot vary based on the currently iterated row. It can only be set table-wide. The <p:columns value> should reference a property in a backing bean. For a real world example, see also this answer: Creating and populating a DataTable dynamically in JSF2.0.
In your particular case, you just basically want to use <ui:repeat> inside <p:column>:
<p:dataTable value="#{tableBean.reportList}" var="report">
<p:column>
#{report.manufacturer}
</p:column>
<p:column>
#{report.color}
</p:column>
<p:column>
<ui:repeat value="#{report.revenue}" var="revenue">#{revenue}</ui:repeat>
</p:column>
</p:dataTable>
(if you want to print them in separate lines, print a <br/> after #{revenue}; or if you want to print them commaseparated, make use of varStatus)
or maybe a nested table:
<p:column>
<h:dataTable value="#{report.revenue}" var="revenue">#{revenue}</h:dataTable>
</p:column>

Answer 2

Try with
<p:column headerText="Manufacturer">#{report.manufacturer}</p:column>
<p:column headerText="Color">#{report.color}</p:column>
<p:columns value="#{tableBean.columns}" var="column">
<f:facet name="header">
#{column.header}
</f:facet>
#{report.revenue.get(column.property)}
</p:columns>
Where in your bean columns is:
List<ColumnModel> columns;
static public class ColumnModel implements Serializable {
private String header;
private int property;
public ColumnModel(String header, int property) {
this.header = header;
this.property = property;
}
public String getHeader() {
return header;
}
public int getProperty() {
return property;
}
}
Filled as follow:
for(int i = 0; i < TOTAL_NUMBER_OF_REVENUES; i++){
ColumnModel col = new ColumnModel("Revenue "+i, i);
columns.add(col);
}
Source : http://www.primefaces.org/showcase/ui/datatableDynamicColumns.jsf