Add Employees, EmployeesDTO, and Q12EmployeesMapping classes for employee management and mapping

Author: kumarcodes

src/main/java/com/topfifty/Employees.java

@@ -0,0 +1,70 @@
+package com.topfifty;
+
+import java.util.Objects;
+
+public class Employees {
+
+    private int id;
+    private String name;
+    private String department;
+    private double salary;
+    private boolean active;
+    private String email;
+
+    public Employees(int id, String name, String department, double salary, boolean active, String email) {
+        this.id = id;
+        this.name = name;
+        this.department = department;
+        this.salary = salary;
+        this.active = active;
+        this.email = email;
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public String getDepartment() {
+        return department;
+    }
+
+    public double getSalary() {
+        return salary;
+    }
+
+    public boolean isActive() {
+        return active;
+    }
+
+    public String getEmail() {
+        return email;
+    }
+
+    // Handy for the "Increment Salary by 10% (Immutable)" style problems,
+    // where you build a new Employee instead of mutating the existing one.
+    public Employees withSalary(double newSalary) {
+        return new Employees(this.id, this.name, this.department, newSalary, this.active, this.email);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (!(o instanceof Employees)) return false;
+        Employees employee = (Employees) o;
+        return id == employee.id;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(id);
+    }
+
+    @Override
+    public String toString() {
+        return "Employee{" + "id=" + id + ", name='" + name + '\'' + ", department='" + department + '\'' + ", salary=" + salary + ", active=" + active + ", email='" + email + '\'' + '}';
+    }
+}

src/main/java/com/topfifty/EmployeesDTO.java

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+package com.topfifty;
+
+
+import java.util.List;
+
+public class EmployeesDTO {
+    public static List<Employees> getEmployees() {
+        return List.of(
+                new Employees(1, "Alice", "Engineering", 60000, true, "alice@co.com"),
+                new Employees(2, "Bob", "Engineering", 55000, true, "bob@co.com"),
+                new Employees(3, "Charlie", "Finance", 70000, false, "charlie@co.com"),
+                new Employees(4, "David", "Finance", 45000, true, "david@co.com"),
+                new Employees(5, "Eve", "HR", 50000, true, "eve@co.com"),
+                new Employees(6, "Frank", "HR", 50000, false, null),
+                new Employees(7, "Grace", "Engineering", 60000, true, "grace@co.com"),
+                new Employees(8, "Alice", "Marketing", 40000, true, "alice2@co.com")
+        );
+    }
+}

src/main/java/com/topfifty/Q12EmployeesMapping.java

@@ -0,0 +1,13 @@
+package com.topfifty;
+
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+public class Q12EmployeesMapping {
+    public static void main(String[] args) {
+        List<Employees> employees = EmployeesDTO.getEmployees();
+        Map<Integer, String> map = employees.stream().collect(Collectors.toMap(Employees::getId, Employees::getName));
+        System.out.println(map);
+    }
+}