Liferay Faces

@ManagedBean
@ViewScoped
public class DataTableBacking implements Serializable {

	// serialVersionUID
	private static final long serialVersionUID = 1715081848553221866L;

	// Injections
	@ManagedProperty(value = "#{customerService}")
	private transient CustomerService customerService;

	// Private Data Members
	private List<Customer> customerDataModel;
	private DataModel<Customer> customerOnDemandDataModel;
	private int rowsPerPage = 10;
	private String selectionMode = "checkbox";
	private String summaryPosition = "bottom";

	public List<Customer> getCustomerDataModel() {

		if (customerDataModel == null) {
			customerDataModel = customerService.getAllCustomers();
		}

		return customerDataModel;
	}

	public DataModel getCustomerOnDemandDataModel() {

		if (customerOnDemandDataModel == null) {
			customerOnDemandDataModel = new CustomerOnDemandDataModel(getRowsPerPage());
		}

		return customerOnDemandDataModel;
	}

	public int getRowsPerPage() {
		return rowsPerPage;
	}

	public String getSelectionMode() {
		return selectionMode;
	}

	public String getSummaryPosition() {
		return summaryPosition;
	}

	public void setCustomerService(CustomerService customerService) {

		// Injected via @ManagedProperty annotation.
		this.customerService = customerService;
	}

	public void setRowsPerPage(int rowsPerPage) {
		this.rowsPerPage = rowsPerPage;
	}

	public void setSelectionMode(String selectionMode) {
		this.selectionMode = selectionMode;
	}

	public void setSummaryPosition(String summaryPosition) {
		this.summaryPosition = summaryPosition;
	}
}

public class CustomerOnDemandDataModel extends OnDemandDataModel<Customer> implements Serializable {

	// serialVersionUID
	private static final long serialVersionUID = 1715725381634521866L;

	// Transient Data members
	private transient CustomerService customerService;
	private int rowsPerPage;

	public CustomerOnDemandDataModel(int rowsPerPage) {
		this.rowsPerPage = rowsPerPage;
	}

	@Override
	public int countRows() {
		return getCustomerService().getCustomerCount();
	}

	@Override
	public List<Customer> findRows(int startRow, int finishRow, List<SortCriterion> sortCriteria) {

		CustomerComparator customerComparator = new CustomerComparator(sortCriteria);
		List<Customer> customers = getCustomerService().getCustomers(startRow, finishRow, customerComparator);

		FacesMessage facesMessage = new FacesMessage("OnDemandDataModel: Fetched row index range " + startRow + "-" +
				finishRow);
		FacesContext facesContext = FacesContext.getCurrentInstance();
		facesContext.addMessage(null, facesMessage);

		return customers;
	}

	@Override
	public int getRowsPerPage() {
		return rowsPerPage;
	}

	protected CustomerService getCustomerService() {

		if (customerService == null) {

			// In order to accommodate clustered environments, the CustomerService is transient and therefore must be
			// self-injected.
			FacesContext facesContext = FacesContext.getCurrentInstance();
			Application application = facesContext.getApplication();
			ELResolver elResolver = application.getELResolver();
			ELContext elContext = facesContext.getELContext();
			customerService = (CustomerService) elResolver.getValue(elContext, null, "customerService");
		}

		return customerService;
	}
}