Paging Calculation Note

Formula to calculate starting row from maxRows: maxRows*(page-1)
Formula to calculate numberOfPages (count + maxRows - 1) / maxRows

public List getCustomers() {
return customerManager.findAllCustomers(MAX_RESULTS * (page-1), MAX_RESULTS);
}

public long getNumOfPages() {
return (customerManager.findAllCustomersCount().longValue() + MAX_RESULTS - 1) / MAX_RESULTS;
}


import java.util.List;

import javax.faces.context.FacesContext;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Controller;

import com.holibi.pharmabeans.db.manager.CustomerManager;
import com.holibi.pharmabeans.db.model.Customer;

@Controller("listCustomerBean")
@Scope("request")
public class ListCustomerBean {
private static final int MAX_RESULTS = 4;

@Autowired
private CustomerManager customerManager;

private int page;

public ListCustomerBean() {
FacesContext context = FacesContext.getCurrentInstance();
String strPage = context.getExternalContext().getRequestParameterMap().get("page");
if (strPage != null) {
page = Integer.parseInt(strPage);
}
if (page <= 1) {
page = 1;
}
}

public List getCustomers() {
return customerManager.findAllCustomers(MAX_RESULTS * (page-1), MAX_RESULTS);
}

public long getNumOfPages() {
return (customerManager.findAllCustomersCount().longValue() + MAX_RESULTS - 1) / MAX_RESULTS;
}

public void action() {
System.out.println("Page: " + page);
}
}