Merge branch 'main' into NileJacksonLesson_15

Author: nilejack

lesson_15/tdd/tdd_app/src/main/java/com/codedifferently/lesson15/EmployeeManager.java

@@ -4,6 +4,7 @@
 import java.util.Map;
 
 public class EmployeeManager {
+
     private Map<Integer, Employee> employees = new HashMap<>();
 
     public void addEmployee(Employee employee) {
@@ -33,5 +34,41 @@ public Map<Integer, Employee> getEmployees() {
     public void setEmployees(Map<Integer, Employee> employees) {
         this.employees = employees;
     }
+
+  private final Map<Integer, Employee> employees;
+
+  public EmployeeManager() {
+    employees = new HashMap<>();
+  }
+
+  public void addEmployee(Employee employee) {
+    employees.put(employee.getId(), employee);
+  }
+
+  public Employee getEmployee(int id) {
+    assertEmployeeInCollection(id);
+    return employees.get(id);
+  }
+
+  public void updateEmployee(Employee employee) {
+    assertEmployeeInCollection(employee.getId());
+    employees.put(employee.getId(), employee);
+  }
+
+  public void removeEmployee(int id) {
+    assertEmployeeInCollection(id);
+    employees.remove(id);
+  }
+
+  private void assertEmployeeInCollection(int id) {
+    if (this.employees.containsKey(id)) {
+      return;
+    }
+    throw new IllegalArgumentException("Employee does not in collection with id " + id);
+  }
+
+  public int getEmployeeCount() {
+    return employees.size();
+  }
 }