src/main/java/com/primefactorsolutions/service/EmployeeService.java

@@ -1,12 +1,10 @@
 package com.primefactorsolutions.service;
 
+import com.primefactorsolutions.model.Candidate;
 import com.primefactorsolutions.model.Employee;
 import com.primefactorsolutions.repositories.EmployeeRepository;
-import org.springframework.data.domain.Page;
-import org.springframework.data.domain.PageRequest;
-import org.springframework.data.domain.Pageable;
 import lombok.Data;
-import org.springframework.data.domain.Sort;
+import org.apache.commons.lang3.NotImplementedException;
 import org.springframework.stereotype.Service;
 
 import java.util.List;
@@ -33,14 +31,4 @@ public class EmployeeService {
     public Employee getEmployee(final UUID id) {
         return null;
     }
-
-    public Page<Employee> getEmployeesPaginated(int pageNo, int pageSize, String sortField, boolean ascending) {
-        Sort sort = ascending ? Sort.by(sortField).ascending() : Sort.by(sortField).descending();
-        Pageable pageable = PageRequest.of(pageNo - 1, pageSize, sort);
-        return employeeRepository.findAll(pageable);
-    }
-
-    public boolean hasNextPage(int currentPage, int pageSize, String sortField, boolean ascending) {
-        return getEmployeesPaginated(currentPage, pageSize, sortField, ascending).hasNext();
-    }
 }

src/main/java/com/primefactorsolutions/views/EmployeesListView.java

@@ -2,18 +2,27 @@ package com.primefactorsolutions.views;
 
 import com.primefactorsolutions.model.Employee;
 import com.primefactorsolutions.service.EmployeeService;
+import com.vaadin.flow.component.ClickEvent;
+import com.vaadin.flow.component.Component;
+import com.vaadin.flow.component.ComponentEventListener;
 import com.vaadin.flow.component.button.Button;
 import com.vaadin.flow.component.combobox.ComboBox;
 import com.vaadin.flow.component.html.H2;
 import com.vaadin.flow.component.html.Main;
 import com.vaadin.flow.component.orderedlayout.HorizontalLayout;
+import com.vaadin.flow.data.provider.DataProvider;
+import com.vaadin.flow.data.provider.DataProviderListener;
+import com.vaadin.flow.data.provider.Query;
+import com.vaadin.flow.function.ValueProvider;
 import com.vaadin.flow.router.PageTitle;
 import com.vaadin.flow.router.Route;
+import com.vaadin.flow.shared.Registration;
 import com.vaadin.flow.spring.annotation.SpringComponent;
 import jakarta.annotation.security.PermitAll;
 import org.springframework.context.annotation.Scope;
 import org.vaadin.firitin.components.grid.VGrid;
-import org.springframework.data.domain.Page;
+
+import java.util.stream.Stream;
 
 @SpringComponent
 @Scope("prototype")
@@ -21,103 +30,97 @@ import org.springframework.data.domain.Page;
 @Route(value = "/employees", layout = MainLayout.class)
 @PermitAll
 public class EmployeesListView extends Main {
-
     private final EmployeeService employeeService;
-    private final int pageSize = 5;
-    private int currentPage = 1;
-    private String sortField = "firstName";
-    private boolean ascending = true;
-    private VGrid<Employee> grid;
-    private Button previous;
-    private Button next;
 
-    public EmployeesListView(EmployeeService employeeService) {
+    public EmployeesListView(final EmployeeService employeeService) {
         this.employeeService = employeeService;
-        addComponents();
-        updateGrid();
-    }
-
-    private void addComponents() {
-        addTitle();
-        addOrderButtons();
-        configureGrid();
-        addNavigationButtons();
-    }
-
-    private void addTitle() {
         final H2 title = new H2("Employees list");
-        add(title);
-    }
-
-    private void addOrderButtons() {
         final HorizontalLayout hl = new HorizontalLayout();
-        hl.add(createOrderButton("Employee List in Ascending Order", true));
+        final HorizontalLayout hf = new HorizontalLayout();
-        hl.add(createOrderButton("Employee List in Descending Order", false));
+        final Button employeeListAscendingOrder  = new Button("Employee List in Ascending Order");
-        add(hl);
+        employeeListAscendingOrder.addClickListener((ComponentEventListener<ClickEvent<Button>>) buttonClickEvent -> {
-    }
+            // no-op
-
-    private Button createOrderButton(String label, boolean isAscending) {
-        Button button = new Button(label);
-        button.addClickListener(event -> {
-            sortField = "firstName";
-            ascending = isAscending;
-            updateGrid();
         });
-        return button;
+        hl.add(employeeListAscendingOrder);
-    }
+        final Button employeeListDescendingOrder  = new Button("Employee List in Descending Order");
-    private void configureGrid() {
+        employeeListDescendingOrder.addClickListener((ComponentEventListener<ClickEvent<Button>>) buttonClickEvent -> {
-        grid = new VGrid<>(Employee.class);
+            // no-op
+        });
+        hl.add(employeeListDescendingOrder);
+        final VGrid<Employee> grid = new VGrid<>(Employee.class);
         grid.setColumns("firstName", "lastName", "status");
         grid.setAllRowsVisible(true);
-        grid.addComponentColumn(employee -> createStatusComboBox()).setHeader("Change Status");
+        grid.addComponentColumn((ValueProvider<Employee, Component>) employee -> {
-        grid.addComponentColumn(employee -> createEditButton());
+            ComboBox<String> statusComboBox = new ComboBox<>();
-        grid.addComponentColumn(employee -> createSaveButton());
+            statusComboBox.setItems("Active", "Inactive");
-        add(grid);
+            return statusComboBox;
-    }
+        }).setHeader("Change Status");
+        grid.addComponentColumn((ValueProvider<Employee, Component>) employee -> {
+            final Button edit = new Button("Edit");
+            edit.addClickListener((ComponentEventListener<ClickEvent<Button>>) buttonClickEvent -> {
+                // no-op
+            });
+            return edit;
+        });
+        grid.addComponentColumn((ValueProvider<Employee, Component>) employee -> {
+            final Button save = new Button("Save");
+            save.addClickListener((ComponentEventListener<ClickEvent<Button>>) buttonClickEvent -> {
+                // no-op
+            });
+            return save;
+        });
 
-    private ComboBox<String> createStatusComboBox() {
+        grid.setDataProvider(new DataProvider<>() {
-        ComboBox<String> statusComboBox = new ComboBox<>();
+            @Override
-        statusComboBox.setItems("Active", "Inactive");
+            public boolean isInMemory() {
-        return statusComboBox;
+                return false;
-    }
+            }
 
-    private Button createEditButton() {
+            @Override
-        return new Button("Edit");
+            public int size(final Query<Employee, Object> query) {
-    }
+                return employeeService.getEmployees().size();
-    private Button createSaveButton() {
+            }
-        return new Button("Save");
-    }
 
-    private void addNavigationButtons() {
+            @Override
-        final HorizontalLayout hf = new HorizontalLayout();
+            public Stream<Employee> fetch(final Query<Employee, Object> query) {
-        previous = createNavigationButton("Previous", -1);
+                int limit = query.getLimit();
-        next = createNavigationButton("Next", 1);
+                int pagerSize = query.getPageSize();
-        hf.add(previous, next, createAddEmployeeButton());
+                int page = query.getPage();
-        add(hf);
+                return employeeService.getEmployees().stream();
-    }
+            }
 
-    private Button createNavigationButton(String label, int increment) {
+            @Override
-        Button button = new Button(label);
+            public void refreshItem(final Employee employee) {
-        button.addClickListener(event -> changePage(increment));
+                // no-op
-        return button;
+            }
-    }
+
-    private void changePage(int increment) {
+            @Override
-        if (increment < 0 && currentPage > 1) {
+            public void refreshAll() {
-            currentPage--;
+                // no-op
-        } else if (increment > 0 && employeeService.hasNextPage(currentPage, pageSize, sortField, ascending)) {
+            }
-            currentPage++;
+
-        }
+            @Override
-        updateGrid();
+            public Registration addDataProviderListener(final DataProviderListener<Employee> dataProviderListener) {
-    }
+                return null;
-    private Button createAddEmployeeButton() {
+            }
-        return new Button("Add Employee", event ->
+        });
-                getUI().flatMap(ui -> ui.navigate(EmployeeView.class, "new"))
+
-        );
+        final Button previous = new Button("Previous");
-    }
+        previous.addClickListener((ComponentEventListener<ClickEvent<Button>>) buttonClickEvent -> {
-    private void updateGrid() {
+            // no-op
-        Page<Employee> page = employeeService.getEmployeesPaginated(currentPage, pageSize, sortField, ascending);
+        });
-        grid.setItems(page.getContent());
+        hf.add(previous);
-        previous.setEnabled(currentPage > 1);
+        final Button next = new Button("Next");
-        next.setEnabled(page.hasNext());
+        next.addClickListener((ComponentEventListener<ClickEvent<Button>>) buttonClickEvent -> {
+            //  no-op
+        });
+        hf.add(next);
+        final Button addEmployee = new Button("Add Employee");
+        addEmployee.addClickListener((ComponentEventListener<ClickEvent<Button>>) buttonClickEvent -> {
+            this.getUI().get().navigate(EmployeeView.class, "new");
+        });
+        hf.add(addEmployee);
+
+        add(title, hl, grid, hf);
     }
 }

src/main/resources/data.sql

@@ -13,15 +13,4 @@ insert into employee (id, version, first_name, last_name, status) values ('e99b7
 insert into employee (id, version, first_name, last_name, status) values ('f6ab3c6d-7078-45f6-9b22-4e37637bfec6', 1, 'Ana', 'Garcia Rojas', 'ACTIVE');
 insert into employee (id, version, first_name, last_name, status) values ('2e2293b1-3f9a-4f3d-abc8-32639b0a5e15', 1, 'Carlos', 'Lopez Mendoza', 'INACTIVE');
 insert into employee (id, version, first_name, last_name, status) values ('4b1c6c35-4627-4b35-b6e9-dc75c68b2c31', 1, 'Maria', 'Fernandez Villca', 'ACTIVE');
-insert into employee (id, version, first_name, last_name, status) values ('afc5c741-f70a-4394-853b-39d51b118927', 1, 'Luis', 'Gutierrez Mamani', 'ACTIVE');
+insert into employee (id, version, first_name, last_name, status) values ('afc5c741-f70a-4394-853b-39d51b118927', 1, 'Luis', 'Gutierrez Mamani', 'ACTIVE');
-insert into employee (id, version, first_name, last_name, status) values ('b2436b82-7b9f-4f0d-9463-f2c3173a45c3', 1, 'Laura', 'Martinez Paredes', 'INACTIVE');
-insert into employee (id, version, first_name, last_name, status) values ('6e6a8a4e-9f6b-44eb-8c69-40acfdc86756', 1, 'Roberto', 'Santos Escobar', 'ACTIVE');
-insert into employee (id, version, first_name, last_name, status) values ('36b0d1c6-bdc0-4d98-94bb-08b9bce3f0d5', 1, 'Valeria', 'Morales Ochoa', 'INACTIVE');
-insert into employee (id, version, first_name, last_name, status) values ('5a1c6d80-58b3-43e3-a5a5-24b4a2d1d54a', 1, 'Jorge', 'Ramirez Tapia', 'ACTIVE');
-insert into employee (id, version, first_name, last_name, status) values ('9d6a5b2e-6d0b-4b89-8d6a-d3f3d1bfc047', 1, 'Sandra', 'Torres Huanca', 'ACTIVE');
-insert into employee (id, version, first_name, last_name, status) values ('f8b3e0c0-0d5a-4e5c-bf9d-207b9b5e8279', 1, 'Felipe', 'Quispe Huanca', 'INACTIVE');
-insert into employee (id, version, first_name, last_name, status) values ('cd80e1d0-9a08-44a6-bd63-2c63eaa003d4', 1, 'Gabriela', 'Rivas Arana', 'ACTIVE');
-insert into employee (id, version, first_name, last_name, status) values ('62d3c1b7-815e-4e96-8d7e-f8c4236bca55', 1, 'Oscar', 'Flores Quiroga', 'INACTIVE');
-insert into employee (id, version, first_name, last_name, status) values ('f20b7c5a-5a67-44f0-9ec1-4c1b8e80de05', 1, 'Marta', 'Vargas Soria', 'ACTIVE');
-insert into employee (id, version, first_name, last_name, status) values ('19b5a76e-d7b1-4b76-8b02-4d0748e85809', 1, 'Andres', 'Espinoza Chura', 'INACTIVE');
-insert into employee (id, version, first_name, last_name, status) values ('5c1a7b82-832d-4f24-8377-54b77b91b6a8', 1, 'Carla', 'Villanueva Arce', 'ACTIVE');