Assignment vedanshugarg

src/main/java/com/cloudsufi/assignment/Q1_SendWithRetry.java

@@ -0,0 +1,39 @@
+package com.cloudsufi.assignment;
+
+public class Q1_SendWithRetry {
+
+    interface NotificationService {
+        void send(String message);
+
+        default void sendWithRetry(String message, int retries) {
+            for (int i = 0; i <= retries; i++) {
+                try {
+                    send(message);
+                    return; // success
+                } catch (RuntimeException e) {
+                    if (i == retries) {
+                        throw e;
+                    }
+                }
+            }
+        }
+    }
+
+    public static void main(String[] args) {
+
+        NotificationService service = new NotificationService() {
+            int attempts = 0;
+
+            @Override
+            public void send(String message) {
+                attempts++;
+                if (attempts == 1) {
+                    throw new RuntimeException("Temporary Glitch");
+                }
+                System.out.println("Email sent successfully on attempt " + attempts);
+            }
+        };
+
+        service.sendWithRetry("Important Update", 3);
+    }
+}

src/main/java/com/cloudsufi/assignment/Q2_StringValidator.java

@@ -0,0 +1,27 @@
+package com.cloudsufi.assignment;
+
+public class Q2_StringValidator {
+
+    @FunctionalInterface
+    interface StringValidator {
+        boolean check(String str);
+    }
+
+    static boolean validate(String value, StringValidator validator) {
+        return validator.check(value);
+    }
+
+    public static void main(String[] args) {
+
+        String input = "Hello";
+
+        boolean isNonEmpty = validate(input, s -> s != null && !s.isEmpty());
+        System.out.println("Is input non-empty: " + isNonEmpty);
+
+        boolean isLengthGreaterThanFive = validate(input, s -> s != null && s.length() > 5);
+        System.out.println("Is input length greater than 5: " + isLengthGreaterThanFive);
+
+        boolean isStartsWithCapitalLetter = validate(input, s -> s != null && !s.isEmpty() && Character.isUpperCase(s.charAt(0)));
+        System.out.println("Is input start with capital letter: " + isStartsWithCapitalLetter);
+    }
+}

src/main/java/com/cloudsufi/assignment/Q3_StreamAPI.java

@@ -0,0 +1,28 @@
+package com.cloudsufi.assignment;
+
+import java.util.List;
+
+public class Q3_StreamAPI {
+
+    static class User {
+        String name;
+        int age;
+
+        public User(String name, int age) {
+            this.name = name;
+            this.age = age;
+        }
+    }
+
+    public static void main(String[] args) {
+        List<User> users = List.of(new User("Vedanshu", 21), new User("Harsh", 23), new User("Anushka", 16));
+
+        List<String> processedNames = users.stream()
+                .filter(user -> user.age >= 18)
+                .map(user -> user.name.toUpperCase())
+                .sorted()
+                .toList();
+
+        System.out.println(processedNames);
+    }
+}

src/main/java/com/cloudsufi/assignment/Q4_Predicate.java

@@ -0,0 +1,17 @@
+package com.cloudsufi.assignment;
+
+import java.util.List;
+import java.util.function.Predicate;
+
+public class Q4_Predicate {
+    public static void main(String[] args) {
+        List<Integer> numbers = List.of(-10, 2, 5, 8, -4);
+
+        Predicate<Integer> isPositive = n -> n > 0;
+        Predicate<Integer> isEven = n -> n % 2 == 0;
+
+        numbers.stream()
+                .filter(isPositive.and(isEven))
+                .forEach(System.out::println);
+    }
+}

src/main/java/com/cloudsufi/assignment/Q5_Optional.java

@@ -0,0 +1,31 @@
+package com.cloudsufi.assignment;
+
+import java.util.Optional;
+
+public class Q5_Optional {
+    record User(String name, boolean isActive) {}
+
+    static Optional<User> findUser(String id) {
+        return switch (id) {
+            case "1" -> Optional.of(new User("Vedanshu", true));  // Active
+            case "2" -> Optional.of(new User("Harsh", false));   // Inactive
+            default  -> Optional.empty();  // Not Found
+        };
+    }
+
+    static void processUser(String id) {
+        findUser(id)
+                .filter(User::isActive)
+                .map(User::name)
+                .ifPresentOrElse(
+                        System.out::println,
+                        () -> System.out.println("User not found")
+                );
+    }
+
+    public static void main(String[] args) {
+        processUser("1");
+        processUser("2");
+        processUser("3");
+    }
+}

src/main/java/com/cloudsufi/assignment/Q6_RecordEmployee.java

@@ -0,0 +1,21 @@
+package com.cloudsufi.assignment;
+
+public class Q6_RecordEmployee {
+    record Employee(int id, double salary) {
+        public Employee {
+            if (salary <= 0) {
+                throw new IllegalArgumentException("Salary should be positive");
+            }
+        }
+
+        public boolean isHighEarner() {
+            return salary > 100000;
+        }
+    }
+
+    public static void main(String[] args) {
+        Employee e = new Employee(1, 50000);
+        System.out.println(e.salary());
+        // e.salary = 60000; // ERROR: Records are immutable (final)
+    }
+}

src/main/java/com/cloudsufi/assignment/Q7_PaymentSystem.java

@@ -0,0 +1,24 @@
+package com.cloudsufi.assignment;
+
+public class Q7_PaymentSystem {
+
+    sealed interface Payment permits CardPayment, UpiPayment {}
+
+    static final class CardPayment implements Payment {}
+    static final class UpiPayment implements Payment {}
+
+    static void process(Payment p) {
+        switch (p) {
+            case CardPayment c -> System.out.println("Processing Card...");
+            case UpiPayment u  -> System.out.println("Processing UPI...");
+        }
+    }
+
+    public static void main() {
+        CardPayment cardPayment = new CardPayment();
+        process(cardPayment);
+
+        UpiPayment upiPayment = new UpiPayment();
+        process(upiPayment);
+    }
+}

src/main/java/com/cloudsufi/assignment/Q8_TextBlocks.java

@@ -0,0 +1,16 @@
+package com.cloudsufi.assignment;
+
+public class Q8_TextBlocks {
+    public static void main(String[] args) {
+        int userId = 101;
+
+        String query = """
+            SELECT id, name, email
+            FROM users
+            WHERE id = %d
+            ORDER BY created_at DESC
+        """.formatted(userId);
+
+        System.out.println(query);
+    }
+}