How to use Consumer Functional Interface in Java

Consumer Functional Interface :- Consumer Functional Interface have one abstract method  name with accept . Consumer Functional Interface accept method takes an object as argument and perform some operation on it . 

 

 public interface Consumer<T>{

 

  public void accept(T object);

  }

Consumer Functional Interface Application 

ConsumerFunctionalInterfaceApplication .java 

package in.jk.java8.consumer;

import java.util.List;

import java.util.function.Consumer;

import in.jk.java8.Employee;

public class ConsumerFunctionalInterfaceApplication {

public static void main(String[] args) {

System.out.println("Consumer Functional Interface Application .... ");

List<Employee> employeeList = Employee.getEmployeeList();

System.out.println("\n--------------- Salary Calculator Consumer  -------------------\n");

Consumer<Employee> consumer = (employee) -> {

                                      int salary = employee.getSalary();

                                      int totalSalary = salary + 1000;

                                      employee.setSalary(totalSalary);

};

employeeList.forEach(employee -> {

                                          consumer.accept(employee);

                                          System.out.println(employee);

});

System.out.println("\n------ Salary Calculator Consumer Implementation By Class --------\n");

Consumer<Employee> SalaryCalculatorConsumer = new SalaryCalculator();

employeeList.forEach(employee -> {

       SalaryCalculatorConsumer.accept(employee);

               System.out.println(employee);

});

      }

}

SalaryCalculator.java

package in.jk.java8.consumer;

import java.util.function.Consumer;

import in.jk.java8.Employee;

public class SalaryCalculator implements Consumer<Employee> {

@Override

public void accept(Employee employee) {

        int salary = employee.getSalary();

        int totalSalary = salary + 1000;

        employee.setSalary(totalSalary);

}

}

Employee.java

package in.jk.java8;

import java.util.ArrayList;

import java.util.List;

public class Employee {

private int empId;

private String name;

private String company;

private int salary;

//Getters and Setters

@Override

public String toString() {

return "Employee [empId=" + empId + ", name=" + name + ", company=" + company + ",                      salary=" + salary + "]";

}

public static  List<Employee>getEmployeeList() {

List<Employee> empList =new ArrayList<Employee>();

Employee  employee = new Employee();

        employee.setEmpId(1);

        employee.setName("J K");

        employee.setCompany("Google");

        employee.setSalary(1000);

        

        Employee  employee1 = new Employee();

        employee1.setEmpId(2);

        employee1.setName("J K");

        employee1.setCompany("Google");

        employee1.setSalary(2000);

        

        Employee  employee2 = new Employee();

        employee2.setEmpId(3);

        employee2.setName("J K");

        employee2.setCompany("Google");

        employee2.setSalary(3000);

        

        Employee  employee3 = new Employee();

        employee3.setEmpId(4);

        employee3.setName("SHA");

        employee3.setCompany("APAR");

        employee3.setSalary(4000);

        

        Employee  employee4 = new Employee();

        employee4.setEmpId(5);

        employee4.setName("HM");

        employee4.setCompany("PAYTM");

        employee4.setSalary(5000);

        

        Employee  employee5 = new Employee();

        employee5.setEmpId(5);

        employee5.setName("HM");

        employee5.setCompany("APAR");

        employee5.setSalary(6000);

        

        Employee  employee6 = new Employee();

        employee6.setEmpId(6);

        employee6.setName("JK");

        employee6.setCompany("APAR");

        employee6.setSalary(7000);

        

        Employee  employee7 = new Employee();

        employee7.setEmpId(7);

        employee7.setName("JK");

        employee7.setCompany("JET BRAINS");

        employee7.setSalary(8000);

        

        Employee  employee8 = new Employee();

        employee8.setEmpId(8);

        employee8.setName("AJ");

        employee8.setCompany("APAR");

        employee8.setSalary(9000);

        

        Employee  employee9 = new Employee();

        employee9.setEmpId(8);

        employee9.setName("AJ");

        employee9.setCompany("ADOBE");

        employee9.setSalary(10000);

        

        empList.add(employee);

        empList.add(employee1);

        empList.add(employee2);

        empList.add(employee3);

        empList.add(employee4);

        empList.add(employee5);

        empList.add(employee6);

        empList.add(employee7);

        empList.add(employee8);

        empList.add(employee9);

return empList;

}

}

Output in Console .....

Consumer Functional Interface Application .... 

--------------- Salary Calculator Consumer  -------------------

Employee [empId=1, name=J K, company=Google, salary=2000]

Employee [empId=2, name=J K, company=Google, salary=3000]

Employee [empId=3, name=J K, company=Google, salary=4000]

Employee [empId=4, name=SHA, company=APAR, salary=5000]

Employee [empId=5, name=HM, company=PAYTM, salary=6000]

Employee [empId=5, name=HM, company=APAR, salary=7000]

Employee [empId=6, name=JK, company=APAR, salary=8000]

Employee [empId=7, name=JK, company=JET BRAINS, salary=9000]

Employee [empId=8, name=AJ, company=APAR, salary=10000]

Employee [empId=8, name=AJ, company=ADOBE, salary=11000]

--------------- Salary Calculator Consumer Implemetation By Class -------------------

Employee [empId=1, name=J K, company=Google, salary=3000]

Employee [empId=2, name=J K, company=Google, salary=4000]

Employee [empId=3, name=J K, company=Google, salary=5000]

Employee [empId=4, name=SHA, company=APAR, salary=6000]

Employee [empId=5, name=HM, company=PAYTM, salary=7000]

Employee [empId=5, name=HM, company=APAR, salary=8000]

Employee [empId=6, name=JK, company=APAR, salary=9000]

Employee [empId=7, name=JK, company=JET BRAINS, salary=10000]

Employee [empId=8, name=AJ, company=APAR, salary=11000]

Employee [empId=8, name=AJ, company=ADOBE, salary=12000]