Show live progress of a long running task using af:progressIndicator in Oracle ADF

This post is about using af:progressIndicator to show live status of a particular task
af:progressIndicator state is tracked and maintained by it's value property that supports org.apache.myfaces.trinidad.model.BoundedRangeModel
This class has two methods

public abstract long getMaximum() { }

returns Maximum value for Model

public abstract long getValue() { }

returns value for Model (current state)

Now to see live progress on page we have to refresh progressIndicator component periodically and this can be achieved using af:poll component , poll component delivers poll events to server periodically and we can ppr (refresh) progress indicator after a particular interval