package java8.a2_streams;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Comparator;

import java.util.List;

import java.util.Optional;

import java.util.stream.Collectors;

import java.util.stream.IntStream;

public class A0_StreamExamples {

public static void main(String[] args) {

// 1. Remove Duplicates From List

List<String> list1 = Arrays.asList("java", "python", "java");

List<String> unique = list1.stream().distinct().collect(Collectors.toList());

System.out.println("1. Unique List: " + unique); // [java, python]

// 2. Sort List in Reverse Order

List<Integer> list2 = Arrays.asList(3, 1, 4, 2);

System.out.print("2. Reverse Sorted List: ");

list2.stream().sorted(Comparator.reverseOrder()).forEach(i -> System.out.print(i + " "));

System.out.println();

// 3. Join Strings with Delimiter, Prefix, Suffix

List<String> names = Arrays.asList("Rizwan", "Ranveer", "Vishaka");

String joined = names.stream().collect(Collectors.joining(", ", "Names: [", "]"));

System.out.println("3. Joined String: " + joined); // Names: [Rizwan, Ranveer, Vishaka]

// 4. Print Multiples of 5

List<Integer> list4 = Arrays.asList(5, 10, 13, 15, 18);

System.out.print("4. Multiples of 5: ");

list4.stream().filter(i -> i % 5 == 0).forEach(i -> System.out.print(i + " "));

System.out.println();

// 5. Maximum in List

List<Integer> list5 = Arrays.asList(10, 20, 30);

int max = list5.stream().max(Integer::compare).get();

System.out.println("5. Maximum: " + max); // 30

// 6. Minimum in List

List<Integer> list6 = Arrays.asList(10, 20, 30);

int min = list6.stream().min(Integer::compare).get();

System.out.println("6. Minimum: " + min); // 10

// 7. Merge Two Arrays Into Sorted List

int[] a = { 1, 3, 5 };

int[] b = { 2, 4, 6 };

int[] merged = IntStream.concat(Arrays.stream(a), Arrays.stream(b)).sorted().toArray();

System.out.println("7. Merged Sorted Array: " + Arrays.toString(merged)); // [1, 2, 3, 4, 5, 6]

// 8. Sum of even Numbers

List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5, 6);

int sum = numbers.stream().filter(n -> n % 2 == 0) // keep even numbers

.mapToInt(Integer::intValue) // map to int (primitive)

.sum(); // sum them

System.out.println("8. Sum of even numbers: " + sum);

// 9. Stream Operations on List of Names

List<String> memberNames = new ArrayList<>();

memberNames.add("Amitabh");

memberNames.add("Shekhar");

memberNames.add("Aman");

memberNames.add("Rahul");

memberNames.add("Shahrukh");

memberNames.add("Salman");

memberNames.add("Yana");

memberNames.add("Lokesh");

System.out.println("9. DataSet for next Operations :: " + memberNames);

// 9.1 Sorted and Uppercase Names

List<String> sortedUpper = memberNames.stream().sorted().map(String::toUpperCase).collect(Collectors.toList());

System.out.println("9.1 Sorted Uppercase Names: " + sortedUpper);

// 9.2 Names Starting with 'A' in Uppercase

List<String> aUpper = memberNames.stream().filter(s -> s.startsWith("A")).map(String::toUpperCase)

.collect(Collectors.toList());

System.out.println("9.2 Names Starting with 'A' in Uppercase: " + aUpper);

// 9.3 Names Starting with 'A'

List<String> aNames = memberNames.stream().filter(s -> s.startsWith("A")).collect(Collectors.toList());

System.out.println("9.3 Names Starting with 'A': " + aNames);

// 9.4 Any name starts with 'A'?

boolean anyStartsWithA = memberNames.stream().anyMatch(s -> s.startsWith("A"));

System.out.println("9.6 Any name starts with 'A'?: " + anyStartsWithA);

// 9.5 All names start with 'A'?

boolean allStartWithA = memberNames.stream().allMatch(s -> s.startsWith("A"));

System.out.println("9.7 All names start with 'A'?: " + allStartWithA);

// 9.6 No name starts with 'A'?

boolean noneStartWithA = memberNames.stream().noneMatch(s -> s.startsWith("A"));

System.out.println("9.8 No name starts with 'A'?: " + noneStartWithA);

// 9.7 Count of names starting with 'A'

long countA = memberNames.stream().filter(s -> s.startsWith("A")).count();

System.out.println("9.9 Count of names starting with 'A': " + countA);

// 9.8 Reduce to single string

Optional<String> reduced = memberNames.stream().reduce((s1, s2) -> s1 + "#" + s2);

System.out.println("9.10 Reduced String: " + reduced.orElse(""));

// 9.9 First name starting with 'L'

Optional<String> firstL = memberNames.stream().filter(s -> s.startsWith("L")).findFirst();

System.out.println("9.11 First name starting with 'L': " + firstL.orElse("Not Found"));

// 10. Stream Reduce Examples

List<String> words = Arrays.asList("apple", "banana", "orange");

String concatWithColon = words.stream().reduce("", (acc, word) -> acc.isEmpty() ? word : acc + ":" + word);

System.out.println("10.1 concatWithColon : " + concatWithColon);

String concat = words.stream().reduce("", String::concat);

System.out.println("10.2 String concat : " + concat);

}

}