p:datatable summary row calculation - primefaces

Question

I have a p:dataTable pretty similar to the showcase.
Unfortunatly, the showcase uses randomly generated values for the p:summaryRow.
Refering to the showcase, imagine the car had a price attribute.
How would I sum up the price for the cars grouped by the specified column for displaying it in the summary row?

Answer 1

I have same problem with you and found correct usage from primefaces blog
SummaryRow from primefaces forum
this is some example show correct calculation for sum price, count...
Listener gets the group property which is the sortBy value which you can use to calculate totals or any other operation.
<p:summaryRow listener="#{backingBean.calculateTotal}">
<p:column colspan="3" style="text-align:right">
Total:
</p:column>
<p:column>
#{backingBean.total}
</p:column>
</p:summaryRow>
/* listener method in your bean */
public void calculateTotal(Object o) {
this.total = 0.0d;
String name = "";
if(o != null) {
if(o instanceof String) {
name = (String) o;
for(MyRowObject p : (List<MyRowObject>) dataTableModel.getWrappedData()) { // The loop should find the sortBy value rows in all dataTable data.
switch(sortColumnCase) { // sortColumnCase was set in the onSort event
case 0:
if(p.getcolumn0data().getName().equals(name)) {
this.total += p.getcolumn0data().getValue();
}
break;
case 1:
if(p.getcolumn1data().getName().equals(name)) {
this.total += p.getcolumn1data().getValue();
}
break;
}
}
}
}
}

Answer 2

this is my solution:
<p:dataTable var="elem" value="#{unitSubStatusChart.resultList}" tableStyleClass="app-table-auto">
<et:defaultPaginator />
<p:column headerText="#{bundle['class']}" sortBy="#{elem.dtype}">
<e:outputIconText icon="#{icons[elem.dtype]}" value="#{bundle[elem.dtype]}" />
</p:column>
<p:column headerText="#{bundle['status']}" sortBy="#{elem.status}">
<h:outputText value="#{bundle[elem.status]}" />
</p:column>
<p:column headerText="#{bundle['subStatus']}" sortBy="#{elem.subStatus}">
<h:outputText value="#{bundle[elem.subStatus]}" />
</p:column>
<p:column headerText="#{bundle['count']}">
<h:outputText value="#{elem.count}" />
</p:column>
<p:summaryRow listener="#{unitSubStatusChart.onSummaryRow}">
<p:column colspan="3" style="text-align:right">
<h:outputText value="#{bundle.total}:" />
</p:column>
<p:column>
<!-- !!! NOTE THIS VALUE EXPRESSION !!! -->
<h:outputText value="#{component.parent.attributes.total}" />
</p:column>
</p:summaryRow>
</p:dataTable>
and this is the listener:
public void onSummaryRow(Object filter)
{
FacesContext facesContext = FacesContext.getCurrentInstance();
ELContext elContext = facesContext.getELContext();
ELResolver elResolver = elContext.getELResolver();
DataTable table = (DataTable) UIComponent.getCurrentComponent(facesContext);
UIColumn sortColumn = table.getSortColumn();
ValueExpression expression = sortColumn.getValueExpression("sortBy");
ValueReference reference = ValueExpressionAnalyzer.getReference(expression);
String property = (String) reference.getProperty();
int total = 0;
List<?> rowList = (List<?>) table.getValue();
for(Object row : rowList)
{
Object value = elResolver.getValue(elContext, row, property);
if(filter.equals(value))
{
// THIS IS THE ONLY POINT TO CUSTOMIZE
total += ((UnitResult) row).getCount();
}
}
List<UIComponent> children = table.getSummaryRow().getChildren();
UIComponent column = children.get(children.size() - 1);
column.getAttributes().put("total", total);
}
This listener has no external references: it does not depend on previous onSort events/listeners and it doesn't need any field in the bean.

Answer 3

I will suggest a possible way to do this, may not be the most perfect, but i believe it will help.
Ther's the steps:
1 - Declare a class atribute to acumulate the total group value:
...
#Named(value = "myBean")
#YourScope
public class InscricaoBean implements Serializable {
...
//in this example i will use a int type
private int acumulatorAux = 0;
...
2 - Create a function to return the total value per group:
...
public int getAcumulatedValue() {
int aux = acumulatorAux ;
acumulatorAux = 0;
return aux;
}
...
3 - Create an method to acumulate values per group:
...
public void acumulateValue(int value)
{
acumulatorAux += value;
}
...
4 - On JSF page, you need to call acumulateValue method for every row, something like:
...
<p:dataTable value="#{myBean.getList()}" var="testVar">
<p:column headerText="Header" sortBy="#{testVar.name}">
#{inscricaoBean.acumulateValue(testVar.value)}
<h:outputText value="#{testVar.name}" />
</p:column>
...
5 - And next, you can have a summaryRow like:
...
<p:summaryRow>
<p:column colspan="1" style="text-align:right">
<h:outputText value="Total:" />
</p:column>
<p:column>
<h:outputText value="#{inscricaoBean.getAcumulatedValue()}" />
</p:column>
</p:summaryRow>
...
Well, this is a gross way to acomplish this task. I think you can improve, but it was the first think when i see your question.
Hope it helps.

Answer 4

by using Lambda expression it works in java 1.7 with EL 3.0
n your JSF it would be like this :
<p:summaryRow>
<p:column colspan="3" style="text-align:right">
<h:outputText value="Total:" />
</p:column>
<p:column>
<h:outputText value="#{car.stream().map(item->item.price).sum()}">
<f:convertNumber type="currency" currencySymbol="$" />
</h:outputText>
</p:column>
</p:summaryRow>

Answer 5

One approach is to pass the datatable's sortBy="#{car.brand}" value within the p:summaryRow into a backing method that uses a stream to compute price subtotal.
<h:form>
<p:dataTable var="car" value="#{dtSummaryRowView.cars}" sortBy="#{car.brand}">
<p:column headerText="Id" sortBy="#{car.id}">
<h:outputText value="#{car.id}" />
</p:column>
<p:column headerText="Year" sortBy="#{car.year}">
<h:outputText value="#{car.year}" />
</p:column>
<p:column headerText="Brand" sortBy="#{car.brand}">
<h:outputText value="#{car.brand}" />
</p:column>
<p:column headerText="Color" sortBy="#{car.color}">
<h:outputText value="#{car.color}" />
</p:column>
<p:summaryRow>
<p:column colspan="3" style="text-align:right">
<h:outputText value="Total:" />
</p:column>
<p:column>
<h:outputText value="#{dtSummaryRowView.brandSubtotal(car.brand)}">
<f:convertNumber type="currency" currencySymbol="$" />
</h:outputText>
</p:column>
</p:summaryRow>
</p:dataTable>
</h:form>
.
public double brandSubtotal(String brand) {
return cars.stream().filter(c -> c.getBrand().equals(brand)).mapToDouble(c -> c.getPrice()).sum();
}
Another approach is to use the listener in p:summaryRow to set a backing bean attribute and then use getter to display the attribute.
<p:summaryRow listener="#{dtSummaryRowView.computeSubtotal(car.brand)}">
<p:column colspan="3" style="text-align:right">
<h:outputText value="Total:" />
</p:column>
<p:column>
<h:outputText value="#{dtSummaryRowView.subTotal}">
<f:convertNumber type="currency" currencySymbol="$" />
</h:outputText>
</p:column>
</p:summaryRow>
.
public void computeSubtotal(String brand) {
subTotal = cars.stream().filter(c -> c.getBrand().equals(brand)).mapToDouble(c -> c.getPrice()).sum();
}
public double getSubTotal () {
return subTotal ;
}