Stream API

      Java 8 Stream API  Basic Examples.

        Let us understand the few ways  where we can use java 8 streams to solve the problems.

github link: https://github.com/RamakanthB/Java8Lamda-Streams

import java.util.Arrays;
import java.util.List;
import java.util.Optional;
import java.util.stream.Collectors;

public class StreamBasics {

    public static void main(String[] args) {

        List<Employee> emplist = getAllEmpData();
       
        System.out.println("*********** Print All Employees Details ***********");
       
        emplist.stream().forEach(System.out::println);

        System.out.println("*********** Only Name of Employees  ***********");
       
        emplist.stream().map(s -> s.getName()).forEach(System.out::println);

        System.out.println("*********** Only DEV Dept Employees ***********");

        emplist.stream().filter(s -> "DEV".equals(s.getDept())).map(s ->
        s.getName()).forEach(System.out::println);

                                             
        System.out.println("***** Only DEV Dept ans store in new List of Beans*****");

        List<Employee> devemplist = emplist.stream().filter(s -> "DEV".equals(s.getDept()))
                .collect(Collectors.toList());
        devemplist.stream().forEach(System.out::println);

        System.out.println("*********** Only STC Project ***********");

        long count = emplist.stream().flatMap(s ->
                             Arrays.stream(s.getProjects())).peek(System.out::println)
                             .filter(s -> s.equals("STC")).count();
        System.out.println("People who are assigned with STC " + count);

        System.out.println("*********** Highest salary ***********");

        Optional<Employee> higestSal = emplist.stream().reduce((s1, s2) -> s1.getSalary() >
        s2.getSalary() ? s1 : s2);
        higestSal.ifPresent(System.out::println);

    }
   
    public static List<Employee> getAllEmpData() {

        List<Employee> emplist = Arrays.asList(
                new Employee("Ramakanth", 20000d, "DEV", 27, new String[] { "STC", "TMOB", "GPAYROLL" }),
                new Employee("Sanjay", 10000d, "TES", 27, new String[] { "IBM", "ACC" }),
                new Employee("Wasim", 17000d, "DEV", 27, new String[] { "STC", "TMOB" }),
                new Employee("Umakanth", 8000d, "AID", 25, new String[] { "NXP" }),
                new Employee("Pavan", 30000d, "DEV", 27, new String[] { "STC", "CGI" }),
                new Employee("Vijay", 10000d, "TES", 27, new String[] {  "TMOB", "GPAYROLL" }),
                new Employee("Debasis", 17000d, "DEV", 27, new String[] {"GPAYROLL" }),
                new Employee("Siva", 8000d, "AID", 27, new String[] { "STC", "TMOB" }),
                new Employee("Hema", 40000d, "DEV", 32, new String[] { "STC", "TMOB", "GPAYROLL" }),
                new Employee("Deepak", 22000d, "TES", 31, new String[] { "TMOB", "GPAYROLL" }));
        return emplist;
    }
}

class Employee {

    private String name;
    private Double salary;
    private String Dept;
    private Integer age;
    private String[] projects;

    public String getName() {
        return name;
    }

    public String[] getProjects() {
        return projects;
    }

    public void setProjects(String[] projects) {
        this.projects = projects;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Double getSalary() {
        return salary;
    }

    public void setSalary(Double salary) {
        this.salary = salary;
    }

    public String getDept() {
        return Dept;
    }

    @Override
    public String toString() {
        return "Employee [name=" + name + ", salary=" + salary + ", Dept=" + Dept + ", age=" + age + ", projects="
                + Arrays.toString(projects) + "]";
    }

    public Employee(String name, Double salary, String dept, Integer age, String[] projects) {
        super();
        this.name = name;
        this.salary = salary;
        Dept = dept;
        this.age = age;
        this.projects = projects;
    }

    public void setDept(String dept) {
        Dept = dept;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }


}