StreamJava8Part1

//Basic Stream Practice Examples
//Queries:https://javabypatel.blogspot.com/2018/06/java-8-stream-practice-problems.html

/*Operations to be done

Get student with exact match name "jayesh"
Get student with matching address "1235"
Get all student having mobile numbers 3333.
Get all student having mobile number 1233 and 1234
Create a List<Student> from the List<TempStudent>
Convert List<Student> to List<String> of student name
Convert List<students> to String
Change the case of List<String>
Sort List<String>
Conditionally apply Filter condition, say if flag is enabled then.
*/

import java.util.*;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import java.util.Comparator;
public class MyClass {
    public static void main(String args[]) {
      Student student1 = new Student(
            "Jayesh",
            22,
            new Address("1234"),
            Arrays.asList(new MobileNumber("1233"), new MobileNumber("3333")));
 
        Student student2 = new Student(
            "Khyati",
            20,
            new Address("1235"),
            Arrays.asList(new MobileNumber("1111"), new MobileNumber("3333"), new MobileNumber("1233")));
 
        Student student3 = new Student(
            "Jason",
            20,
            new Address("1236"),
            Arrays.asList(new MobileNumber("3333"), new MobileNumber("4444")));
            
            List<Student> students = Arrays.asList(student1, student2, student3);
        
        //      Get student with exact match name "jayesh"
        //---------------------------------------------------------------------------------------
        Optional<Student> stud = students.stream()
            .filter(student -> student.getName().equals("Jayesh"))
            .findFirst();
        System.out.println(stud.isPresent() ? stud.get().getName() : "No student found");
        //----------------------------------------------------------------------------------------
       
       // Sort student list in descending order based on student's name
       //---------------------------------------------------------------------------------------------------------------------------------
        List<Student> stud=students.stream().sorted(Comparator.comparing(Student::getName).reversed()).collect(Collectors.toList());
        for(Student i:stud){System.out.println(i.toString());}
        //---------------------------------------------------------------------------------------------------------------------------------
        
        //Get student with matching address "1235"
        //---------------------------------------------------------------------------------------------------------------------------------
        Optional<Student> studAdd=students.stream().filter(i->i.getAddress().getZipcode()=="1235").findFirst();
        System.out.println(studAdd.toString());
        //---------------------------------------------------------------------------------------------------------------------------------
         
        //Get all student having mobile numbers 3333, then sort based on age, if age is equal sort based on name
        //---------------------------------------------------------------------------------------------------------------------------------
        List<Student> studm=students.stream().filter(i->i.getMobileNumbers().stream().anyMatch(x->x.getNumber().equals("3333"))).sorted(Comparator.comparing(Student::getAge).thenComparing(Student::getName)).collect(Collectors.toList());
        for(Student i:studm){System.out.println(i.toString());}
        //---------------------------------------------------------------------------------------------------------------------------------
        
        //Get all student having mobile number 1233 and 1234
        //---------------------------------------------------------------------------------------------------------------------------------
        List<Student> stud3 = students.stream()
            .filter(student -> student.getMobileNumbers().stream().allMatch(x -> Objects.equals(x.getNumber(), "1233") || Objects.equals(x.getNumber(), "1234")))
            .collect(Collectors.toList());
         //---------------------------------------------------------------------------------------------------------------------------------
         
        //Create a List<Student> from the List<TempStudent>
        //---------------------------------------------------------------------------------------------------------------------------------
        TempStudent tmpStud1 = new TempStudent(
            "Jayesh1",
            201,
            new Address("12341"),
            Arrays.asList(new MobileNumber("12331"), new MobileNumber("12341")));
 
        TempStudent tmpStud2 = new TempStudent(
            "Khyati1",
            202,
            new Address("12351"),
            Arrays.asList(new MobileNumber("11111"), new MobileNumber("33331"), new MobileNumber("12331")));
 
        List<TempStudent> tmpStudents = Arrays.asList(tmpStud1, tmpStud2);
        
        List<Student> studList=tmpStudents.stream().map(t->new Student(t.name,t.age,t.address,t.mobileNumbers)).collect(Collectors.toList());
        System.out.println();
         for(Student i:studList){System.out.println(i.toString());}
         //---------------------------------------------------------------------------------------------------------------------------------
         
         //Convert List<Student> to List<String> of student name 
         //---------------------------------------------------------------------------------------------------------------------------------
         List<String> nameList=studList.stream().map(Student::getName).collect(Collectors.toList());
         for(String i:nameList){System.out.println(i);}
         //---------------------------------------------------------------------------------------------------------------------------------
         
         //Convert List<students> to String
         //---------------------------------------------------------------------------------------------------------------------------------
         String name=nameList.stream().map(i->i).collect(Collectors.joining(",","[","]"));
         System.out.println(name);
         //---------------------------------------------------------------------------------------------------------------------------------
         
         //Change the case of List<String>, Sort List<String> in descending order
         //---------------------------------------------------------------------------------------------------------------------------------
         nameList.stream().map(String::toUpperCase).sorted(Comparator.reverseOrder()).forEach(System.out::println);
         //---------------------------------------------------------------------------------------------------------------------------------
         /*Here key imp concept, lambda doesn't work with boolean coz boolean is not a functional interface*/
         /*You can use forEach as a terminal operator too*/  
    }
}
class TempStudent {
    public String name;
    public int age;
    public Address address;
    public List<MobileNumber> mobileNumbers;
 
    public TempStudent(String name, int age, Address address, List<MobileNumber> mobileNumbers) {
        this.name = name;
        this.age = age;
        this.address = address;
        this.mobileNumbers = mobileNumbers;
    }
}
 
class Student{
    private String name;
    private int age;
    private Address address;
    private List<MobileNumber> mobileNumbers;
 
    public Student(String name, int age, Address address, List<MobileNumber> mobileNumbers) {
        this.name = name;
        this.age = age;
        this.address = address;
        this.mobileNumbers = mobileNumbers;
    }
 
    public String getName() {
        return name;
    }
 
    public int getAge() {
        return age;
    }
 
    public Address getAddress() {
        return address;
    }
 
    public List<MobileNumber> getMobileNumbers() {
        return mobileNumbers;
    }
 
    public void setName(String name) {
        this.name = name;
    }
 
    public void setAge(int age) {
        this.age = age;
    }
 
    public void setAddress(Address address) {
        this.address = address;
    }
 
    public void setMobileNumbers(List<MobileNumber> mobileNumbers) {
        this.mobileNumbers = mobileNumbers;
    }
 
    @Override
    public String toString() {
        return "Student{" +
            "name='" + name + '\'' +
            ", age=" + age +
            ", address=" + address +
            ", mobileNumbers=" + mobileNumbers +
            '}';
    }
}
 
class Address{
    private String zipcode;
 
    public Address(String zipcode) {
        this.zipcode = zipcode;
    }
 
    public String getZipcode() {
        return zipcode;
    }
 
    public void setZipcode(String zipcode) {
        this.zipcode = zipcode;
    }
}
 
class MobileNumber{
    private String number;
 
    public MobileNumber(String number) {
        this.number = number;
    }
 
    public String getNumber() {
        return number;
    }
 
    public void setNumber(String number) {
        this.number = number;
    }
}