ADF - The value attribute of SelectMany components

The selection components allow the user to select single and multiple values from a list or group of items. The value attribute of SelectOne components is straightforward, but what about the value of SelectMany components?

ADF Faces provides a number of SelectMany components. The selectManyCheckbox component is one of them which allows the user to select multiple values from a series of checkboxes. In the Tag Reference of the component, the type of the value attibute is Object, and the description:

the value of the component. If the EL binding for the "value" points to a bean property with a getter but no setter, and this is an editable component, the component will be rendered in read-only mode.

Simply the same as it for other components. Not much helpful. After some digging, I found the following code snippet:

// org.apache.myfaces.trinidadinternal.renderkit.core.xhtml.SimpleSelectManyRenderer

// OK, is this a List or an array?
boolean isList = ((modelClass == null) ||
                  modelClass.isAssignableFrom(List.class));
boolean isArray = (modelClass != null) && modelClass.isArray();
// We only support lists and arrays;  if neither, quit.
if (!isList && !isArray)
{
  _throwUnsupportedModelType(context, modelClass, component);
}

Clearly, the value attribute of SelectMany components, must be a List or an Array, and the default type is List.

You can download the sample application - SelectManyCheckbox.jws. This application demonstrates how to handle the value attribute and process the selected items of the selectManyCheckbox component.

In this sample application. The value attribute of one of selectManyCheckbox components is designed to be an Array; and the other one is left simply as an Object.

private Weekday[] days = new Weekday[] { Weekday.Sunday, Weekday.Saturday };
private Object sports;

Once the user makes some selections on both components, and submit. You can find the message from the Log Window like this:

>>> days: [Lcom.adfsamples.view.beans.SelectManyBean$Weekday;
>>> sports: java.util.ArrayList

The data type of the first component (days) is an Array as expected, and the second one (sports) is handled as an ArrayList, the default data type for the value attribute.

Sample Applications:

• Source Code
• Download ZIP

Environment:

• Oracle Alta UI
• JDeveloper 12.1.3.0.0 Build JDEVADF12.1.3.0.0GENERIC_140521.1008.S
• Safari Version 8.0.2 (10600.2.5)
• Mac OS X Version 10.10.1 (Yosemite)

Resources:

Oracle Fusion Middleware Tag Reference for Oracle ADF Faces 12c (12.1.3)