JSF: Bulk update capable, but cannot update one row in datatable
I have a simple data object: Car. I am showing properties of Car objects in JSF datatable. If I display the properties using inputText tags, I can get the changed values in the managed bean. However, I just want one line to be editable. Therefore, we placed the edit button in a separate column and inputText and outputText for each Car property. the edit button just toggles rendering of inputText and outputText. Also, I have placed the refresh button in a separate column that is used to save the updated values. However, when I click the refresh button, I still get the old values instead of the changed values. Here's the complete code:
public class Car {
int id;
String brand;
String color;
public Car(int id, String brand, String color) {
this.id = id;
this.brand = brand;
this.color = color;
}
//getters and setters of id, brand, color
}
Here is the managed bean:
import java.util.ArrayList;
import java.util.List;
import javax.faces.bean.ManagedBean;
import javax.faces.bean.RequestScoped;
import javax.faces.component.UIData;
@ManagedBean(name = "CarTree")
@RequestScoped
public class CarTree {
int editableRowId;
List<Car> carList;
private UIData myTable;
public CarTree() {
carList = new ArrayList<Car>();
carList.add(new Car(1, "jaguar", "grey"));
carList.add(new Car(2, "ferari", "red"));
carList.add(new Car(3, "camri", "steel"));
}
public String update() {
System.out.println("updating...");
//below statments print old values, was expecting modified values
System.out.println("new car brand is:" + ((Car) myTable.getRowData()).brand);
System.out.println("new car color is:" + ((Car) myTable.getRowData()).color);
//how to get modified row values in this method??
return null;
}
public int getEditableRowId() {
return editableRowId;
}
public void setEditableRowId(int editableRowId) {
this.editableRowId = editableRowId;
}
public UIData getMyTable() {
return myTable;
}
public void setMyTable(UIData myTable) {
this.myTable = myTable;
}
public List<Car> getCars() {
return carList;
}
public void setCars(List<Car> carList) {
this.carList = carList;
}
}
here is the JSF page 2:
<?xml version='1.0' encoding='UTF-8' ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:f="http://java.sun.com/jsf/core">
<h:head>
<title>Facelet Title</title>
</h:head>
<h:body>
<h:form id="carForm" prependId="false">
<h:dataTable id="dt" binding="#{CarTree.myTable}" value="#{CarTree.cars}" var="car" >
<h:column>
<h:outputText value="#{car.id}" />
</h:column>
<h:column>
<h:outputText value="#{car.brand}" rendered="#{CarTree.editableRowId != car.id}"/>
<h:inputText value="#{car.brand}" rendered="#{CarTree.editableRowId == car.id}"/>
</h:column>
<h:column>
<h:outputText value="#{car.color}" rendered="#{CarTree.editableRowId != car.id}"/>
<h:inputText value="#{car.color}" rendered="#{CarTree.editableRowId == car.id}"/>
</h:column>
<h:column>
<h:commandButton value="edit">
<f:setPropertyActionListener target="#{CarTree.editableRowId}" value="#{car.id}" />
</h:commandButton>
</h:column>
<h:column>
<h:commandButton value="update" action="#{CarTree.update}"/>
</h:column>
</h:dataTable>
</h:form>
</h:body>
</html>
However, if I just keep the inputText tags and remove the rendered attributes, I get the changed values in the update method. How can I get the modified values to edit one line?
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I am getting changed values in the update method when the scope changes from request to session. Is there a better approach instead of using SessionScoped? SessionScoped == Server memory, so I want to avoid it.
Rant (or disappointment?): Indeed, if there was something similar to the asp.net ObjectDataSource it would be much easier. Even to moderately work with data related to data, we have to look for a life cycle. Whereas in asp.net ObjectDataSource + ListView the combo is enough for most data + UI questions and we hardly have to look for the control lifecycle (Infact, the asp.net guys almost never look for docs). Why use the underlying JSF specification for a control capable of doing CRUD operations out of the box, possibly with lazy loading capability. is not required for every application?
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JSF has already updated the model values for you. Just use it in the usual way.
public String update() {
for (Car car : carList) {
if (/* this item was set to editmode */) {
System.out.println("new car brand is:" + car.brand);
System.out.println("new car color is:" + car.color);
}
}
return null;
}
By the way, creating model properties is not private
a bad idea. You have to make them private
and access them using getters / setters. That is car.getBrand()
, car.getColor()
etc.
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