All advanced sorting techniques using Java 8 and Streams

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package com.dpq.interview.Q;

import java.math.BigInteger;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Date;
import java.util.List;

public class SortingDemo {
public static void main(String[] args) throws ParseException {
allSortingTechniquesAfterJava8();
}

public static void allSortingTechniquesAfterJava8() throws ParseException {
List<Employee> list = populateList();
System.out.println(“####################################### Natiral soring by Employee Id ###############################################”);
list.stream().sorted().forEach(e -> System.out.println(e));
System.out.println(“####################################### Natiral soring by Employee Id but in desending order ###############################################”);
list.stream().sorted(Collections.reverseOrder()).forEach(e -> System.out.println(e));
List<Employee> sortedList = list.stream().sorted(Collections.reverseOrder()).toList();
System.out.println(“Sorting in decending order: “+ sortedList);

System.out.println(“####################################### soring by comparator ###############################################”);
List<Emp> empList = populateEmpList();
empList.sort((o1,o2) -> o1.getEmployeeName().toLowerCase().compareTo(o2.getEmployeeName().toLowerCase()));

empList.forEach(System.out::println);
System.out.println(“####################################### soring by comparator another way ###############################################”);
List<Emp> empList1 = populateEmpList();
empList1.sort(Comparator.comparing(Emp::getEmployeeName).reversed());
empList1.forEach(System.out::println);

System.out.println(“####################################### soring by comparator by Date ###############################################”);
empList1.sort(Comparator.comparing(Emp::getDateOfJoining));
empList1.forEach(System.out::println);

System.out.println(“####################################### soring by comparator by Address ###############################################”);
empList1.sort(Comparator.comparing(t -> ((Emp)t).getEmployeeAddress().getEmployeeAddress()));
empList1.forEach(System.out::println);

System.out.println(“####################################### soring by comparator by Address another way ###############################################”);
empList1.sort((o1,o2) -> o1.getEmployeeAddress().getEmployeeAddress().compareTo(o2.getEmployeeAddress().getEmployeeAddress()));
empList1.forEach(System.out::println);

System.out.println(“####################################### soring by comparator by Address another way ###############################################”);
System.out.println(empList1.parallelStream().anyMatch(e -> e.getEmployeeName().equalsIgnoreCase(“deepak”))); //true
System.out.println(empList1.parallelStream().allMatch(e -> e.getEmployeeName().equalsIgnoreCase(“deepak”))); //false

new Thread( ()-> {
System.out.println(Thread.currentThread());
}).start();;

new Thread( ()-> {
System.out.println(Thread.currentThread());
}).start();;

new Thread( ()-> {
System.out.println(Thread.currentThread());
}).start();;
}

public static List<Emp> populateEmpList() throws ParseException{
List<Emp> list = new ArrayList<>();

list.add(new Emp(50,”deepak”,new SimpleDateFormat(“dd-MM-yyyy”).parse(“14-06-1984”),new BigInteger(“150000″),new EmployeeAddress(50,”Gwalior”)));
list.add(new Emp(40,”DPQ”,new SimpleDateFormat(“dd-MM-yyyy”).parse(“14-06-1984”),new BigInteger(“130000″),new EmployeeAddress(40,”Gwalior”)));
list.add(new Emp(10,”Shiob”,new SimpleDateFormat(“dd-MM-yyyy”).parse(“12-06-1984”),new BigInteger(“250000″),new EmployeeAddress(10,”Hydrabad”)));
list.add(new Emp(20,”Himanshu”,new SimpleDateFormat(“dd-MM-yyyy”).parse(“14-06-2000”),new BigInteger(“50000″),new EmployeeAddress(20,”Indore”)));
list.add(new Emp(30,”Gagan”,new SimpleDateFormat(“dd-MM-yyyy”).parse(“30-06-1982”),new BigInteger(“15000″),new EmployeeAddress(30,”UK”)));
return list;
}

public static List<Employee> populateList() throws ParseException{
List<Employee> list = new ArrayList<>();
list.add(new Employee(50,”deepak”,new SimpleDateFormat(“dd-MM-yyyy”).parse(“14-06-1984”),new BigInteger(“150000″),new Address(50,”Gwalior”)));
list.add(new Employee(40,”DPQ”,new SimpleDateFormat(“dd-MM-yyyy”).parse(“14-06-1984”),new BigInteger(“130000″),new Address(40,”Gwalior”)));
list.add(new Employee(10,”Shiob”,new SimpleDateFormat(“dd-MM-yyyy”).parse(“12-06-1984”),new BigInteger(“250000″),new Address(10,”Hydrabad”)));
list.add(new Employee(20,”Himanshu”,new SimpleDateFormat(“dd-MM-yyyy”).parse(“14-06-2000”),new BigInteger(“50000″),new Address(20,”Indore”)));
list.add(new Employee(30,”Gagan”,new SimpleDateFormat(“dd-MM-yyyy”).parse(“30-06-1982”),new BigInteger(“15000″),new Address(30,”UK”)));
return list;
}

public static void allSortingTechniquesBeforeJava8() throws ParseException {
List<Employee> list = populateList();
System.out.println(“################################################ Before Sorting #################################################”);
System.out.println(list);
System.out.println(“################################################ After Sorting by employeeId using comparable and compareTo method #################################################”);
Collections.sort(list);
System.out.println(list);
System.out.println(“################################################ Sorting based on SortByEmployeeDateOfJoining #################################################”);
Collections.sort(list,new SortByEmployeeDateOfJoining());
System.out.println(list);
System.out.println(“################################################ Sorting based on SortByEmployeeName #################################################”);
Collections.sort(list,new SortByEmployeeName());
System.out.println(list);
System.out.println(“################################################ Sorting based on SortByEmployeeSalary #################################################”);
Collections.sort(list,new SortByEmployeeSalary());
System.out.println(list);
System.out.println(“################################################ Sorting based on SortByEmployeeId from Address #################################################”);
Collections.sort(list,new SortByEmployeeAddressID());
System.out.println(list);

System.out.println(“################################################ Sorting based on SortByEmployee Address #################################################”);
Collections.sort(list,new SortByEmployeeAddress());
System.out.println(list);
}
}

class Employee implements Comparable<Employee>{
private Integer employeeId;
private String employeeName;
private Date dateOfJoining;
private BigInteger salary;
private Address employeeAddress;

public Employee(Integer employeeId, String employeeName, Date dateOfJoining, BigInteger salary,
Address employeeAddress) {
super();
this.employeeId = employeeId;
this.employeeName = employeeName;
this.dateOfJoining = dateOfJoining;
this.salary = salary;
this.employeeAddress = employeeAddress;
}

@Override
public int compareTo(Employee o) {
// TODO Auto-generated method stub
return employeeId – o.employeeId;
}

public Integer getEmployeeId() {
return employeeId;
}
public String getEmployeeName() {
return employeeName;
}
public Date getDateOfJoining() {
return dateOfJoining;
}
public BigInteger getSalary() {
return salary;
}
public Address getEmployeeAddress() {
return employeeAddress;
}
@Override
public String toString() {
return “Employee [employeeId=” + employeeId + “, employeeName=” + employeeName + “, dateOfJoining=”
+ dateOfJoining + “, salary=” + salary + “, employeeAddress=” + employeeAddress + “]”;
}
}

class Emp{
private Integer employeeId;
private String employeeName;
private Date dateOfJoining;
private BigInteger salary;
private EmployeeAddress employeeAddress;

public Emp(Integer employeeId, String employeeName, Date dateOfJoining, BigInteger salary,
EmployeeAddress employeeAddress) {
super();
this.employeeId = employeeId;
this.employeeName = employeeName;
this.dateOfJoining = dateOfJoining;
this.salary = salary;
this.employeeAddress = employeeAddress;
}

public Integer getEmployeeId() {
return employeeId;
}
public String getEmployeeName() {
return employeeName;
}
public Date getDateOfJoining() {
return dateOfJoining;
}
public BigInteger getSalary() {
return salary;
}
public EmployeeAddress getEmployeeAddress() {
return employeeAddress;
}
@Override
public String toString() {
return “Employee [employeeId=” + employeeId + “, employeeName=” + employeeName + “, dateOfJoining=”
+ dateOfJoining + “, salary=” + salary + “, employeeAddress=” + employeeAddress + “]”;
}
}

class SortByEmployeeName implements Comparator<Employee>{
@Override
public int compare(Employee o1, Employee o2) {
return o1.getEmployeeName().compareTo(o2.getEmployeeName());
}
}

class SortByEmployeeDateOfJoining implements Comparator<Employee>{
@Override
public int compare(Employee o1, Employee o2) {
return o1.getDateOfJoining().compareTo(o2.getDateOfJoining());
}
}

class SortByEmployeeSalary implements Comparator<Employee>{
@Override
public int compare(Employee o1, Employee o2) {
return o1.getSalary().compareTo(o2.getSalary());
}
}

class SortByEmployeeAddressID implements Comparator<Employee>{
@Override
public int compare(Employee o1, Employee o2) {
return o1.getEmployeeAddress().compareTo(o2.getEmployeeAddress());
}
}

class SortByEmployeeAddress implements Comparator<Employee>{
@Override
public int compare(Employee o1, Employee o2) {
return o1.getEmployeeAddress().getEmployeeAddress().compareTo(o2.getEmployeeAddress().getEmployeeAddress());
}
}

class Address implements Comparable<Address>{
private Integer employeeId;
private String employeeAddress;

public Address(Integer employeeId, String employeeAddress) {
super();
this.employeeId = employeeId;
this.employeeAddress = employeeAddress;
}

@Override
public int compareTo(Address address) {
// TODO Auto-generated method stub
return employeeId – address.employeeId;
}

public Integer getEmployeeId() {
return employeeId;
}

public String getEmployeeAddress() {
return employeeAddress;
}

@Override
public String toString() {
return “Address [employeeId=” + employeeId + “, employeeAddress=” + employeeAddress + “]”;
}
}

class EmployeeAddress{
private Integer employeeId;
private String employeeAddress;

public EmployeeAddress(Integer employeeId, String employeeAddress) {
super();
this.employeeId = employeeId;
this.employeeAddress = employeeAddress;
}

public Integer getEmployeeId() {
return employeeId;
}

public String getEmployeeAddress() {
return employeeAddress;
}

@Override
public String toString() {
return “Address [employeeId=” + employeeId + “, employeeAddress=” + employeeAddress + “]”;
}
}

Output:

####################################### Natiral soring by Employee Id ###############################################

Employee [employeeId=10, employeeName=Shiob, dateOfJoining=Tue Jun 12 00:00:00 IST 1984, salary=250000, employeeAddress=Address [employeeId=10, employeeAddress=Hydrabad]]

Employee [employeeId=20, employeeName=Himanshu, dateOfJoining=Wed Jun 14 00:00:00 IST 2000, salary=50000, employeeAddress=Address [employeeId=20, employeeAddress=Indore]]

Employee [employeeId=30, employeeName=Gagan, dateOfJoining=Wed Jun 30 00:00:00 IST 1982, salary=15000, employeeAddress=Address [employeeId=30, employeeAddress=UK]]

Employee [employeeId=40, employeeName=DPQ, dateOfJoining=Thu Jun 14 00:00:00 IST 1984, salary=130000, employeeAddress=Address [employeeId=40, employeeAddress=Gwalior]]

Employee [employeeId=50, employeeName=deepak, dateOfJoining=Thu Jun 14 00:00:00 IST 1984, salary=150000, employeeAddress=Address [employeeId=50, employeeAddress=Gwalior]]

####################################### Natiral soring by Employee Id but in desending order ###############################################

Employee [employeeId=50, employeeName=deepak, dateOfJoining=Thu Jun 14 00:00:00 IST 1984, salary=150000, employeeAddress=Address [employeeId=50, employeeAddress=Gwalior]]

Employee [employeeId=40, employeeName=DPQ, dateOfJoining=Thu Jun 14 00:00:00 IST 1984, salary=130000, employeeAddress=Address [employeeId=40, employeeAddress=Gwalior]]

Employee [employeeId=30, employeeName=Gagan, dateOfJoining=Wed Jun 30 00:00:00 IST 1982, salary=15000, employeeAddress=Address [employeeId=30, employeeAddress=UK]]

Employee [employeeId=20, employeeName=Himanshu, dateOfJoining=Wed Jun 14 00:00:00 IST 2000, salary=50000, employeeAddress=Address [employeeId=20, employeeAddress=Indore]]

Employee [employeeId=10, employeeName=Shiob, dateOfJoining=Tue Jun 12 00:00:00 IST 1984, salary=250000, employeeAddress=Address [employeeId=10, employeeAddress=Hydrabad]]

Sorting in decending order: [Employee [employeeId=50, employeeName=deepak, dateOfJoining=Thu Jun 14 00:00:00 IST 1984, salary=150000, employeeAddress=Address [employeeId=50, employeeAddress=Gwalior]], Employee [employeeId=40, employeeName=DPQ, dateOfJoining=Thu Jun 14 00:00:00 IST 1984, salary=130000, employeeAddress=Address [employeeId=40, employeeAddress=Gwalior]], Employee [employeeId=30, employeeName=Gagan, dateOfJoining=Wed Jun 30 00:00:00 IST 1982, salary=15000, employeeAddress=Address [employeeId=30, employeeAddress=UK]], Employee [employeeId=20, employeeName=Himanshu, dateOfJoining=Wed Jun 14 00:00:00 IST 2000, salary=50000, employeeAddress=Address [employeeId=20, employeeAddress=Indore]], Employee [employeeId=10, employeeName=Shiob, dateOfJoining=Tue Jun 12 00:00:00 IST 1984, salary=250000, employeeAddress=Address [employeeId=10, employeeAddress=Hydrabad]]]

#######################################  soring by comparator ###############################################

Employee [employeeId=50, employeeName=deepak, dateOfJoining=Thu Jun 14 00:00:00 IST 1984, salary=150000, employeeAddress=Address [employeeId=50, employeeAddress=Gwalior]]

Employee [employeeId=40, employeeName=DPQ, dateOfJoining=Thu Jun 14 00:00:00 IST 1984, salary=130000, employeeAddress=Address [employeeId=40, employeeAddress=Gwalior]]

Employee [employeeId=30, employeeName=Gagan, dateOfJoining=Wed Jun 30 00:00:00 IST 1982, salary=15000, employeeAddress=Address [employeeId=30, employeeAddress=UK]]

Employee [employeeId=20, employeeName=Himanshu, dateOfJoining=Wed Jun 14 00:00:00 IST 2000, salary=50000, employeeAddress=Address [employeeId=20, employeeAddress=Indore]]

Employee [employeeId=10, employeeName=Shiob, dateOfJoining=Tue Jun 12 00:00:00 IST 1984, salary=250000, employeeAddress=Address [employeeId=10, employeeAddress=Hydrabad]]

#######################################  soring by comparator another way ###############################################

Employee [employeeId=50, employeeName=deepak, dateOfJoining=Thu Jun 14 00:00:00 IST 1984, salary=150000, employeeAddress=Address [employeeId=50, employeeAddress=Gwalior]]

Employee [employeeId=10, employeeName=Shiob, dateOfJoining=Tue Jun 12 00:00:00 IST 1984, salary=250000, employeeAddress=Address [employeeId=10, employeeAddress=Hydrabad]]

Employee [employeeId=20, employeeName=Himanshu, dateOfJoining=Wed Jun 14 00:00:00 IST 2000, salary=50000, employeeAddress=Address [employeeId=20, employeeAddress=Indore]]

Employee [employeeId=30, employeeName=Gagan, dateOfJoining=Wed Jun 30 00:00:00 IST 1982, salary=15000, employeeAddress=Address [employeeId=30, employeeAddress=UK]]

Employee [employeeId=40, employeeName=DPQ, dateOfJoining=Thu Jun 14 00:00:00 IST 1984, salary=130000, employeeAddress=Address [employeeId=40, employeeAddress=Gwalior]]

#######################################  soring by comparator by Date ###############################################

Employee [employeeId=30, employeeName=Gagan, dateOfJoining=Wed Jun 30 00:00:00 IST 1982, salary=15000, employeeAddress=Address [employeeId=30, employeeAddress=UK]]

Employee [employeeId=10, employeeName=Shiob, dateOfJoining=Tue Jun 12 00:00:00 IST 1984, salary=250000, employeeAddress=Address [employeeId=10, employeeAddress=Hydrabad]]

Employee [employeeId=50, employeeName=deepak, dateOfJoining=Thu Jun 14 00:00:00 IST 1984, salary=150000, employeeAddress=Address [employeeId=50, employeeAddress=Gwalior]]

Employee [employeeId=40, employeeName=DPQ, dateOfJoining=Thu Jun 14 00:00:00 IST 1984, salary=130000, employeeAddress=Address [employeeId=40, employeeAddress=Gwalior]]

Employee [employeeId=20, employeeName=Himanshu, dateOfJoining=Wed Jun 14 00:00:00 IST 2000, salary=50000, employeeAddress=Address [employeeId=20, employeeAddress=Indore]]

#######################################  soring by comparator by Address ###############################################

Employee [employeeId=50, employeeName=deepak, dateOfJoining=Thu Jun 14 00:00:00 IST 1984, salary=150000, employeeAddress=Address [employeeId=50, employeeAddress=Gwalior]]

Employee [employeeId=40, employeeName=DPQ, dateOfJoining=Thu Jun 14 00:00:00 IST 1984, salary=130000, employeeAddress=Address [employeeId=40, employeeAddress=Gwalior]]

Employee [employeeId=10, employeeName=Shiob, dateOfJoining=Tue Jun 12 00:00:00 IST 1984, salary=250000, employeeAddress=Address [employeeId=10, employeeAddress=Hydrabad]]

Employee [employeeId=20, employeeName=Himanshu, dateOfJoining=Wed Jun 14 00:00:00 IST 2000, salary=50000, employeeAddress=Address [employeeId=20, employeeAddress=Indore]]

Employee [employeeId=30, employeeName=Gagan, dateOfJoining=Wed Jun 30 00:00:00 IST 1982, salary=15000, employeeAddress=Address [employeeId=30, employeeAddress=UK]]

#######################################  soring by comparator by Address another way ###############################################

Employee [employeeId=50, employeeName=deepak, dateOfJoining=Thu Jun 14 00:00:00 IST 1984, salary=150000, employeeAddress=Address [employeeId=50, employeeAddress=Gwalior]]

Employee [employeeId=40, employeeName=DPQ, dateOfJoining=Thu Jun 14 00:00:00 IST 1984, salary=130000, employeeAddress=Address [employeeId=40, employeeAddress=Gwalior]]

Employee [employeeId=10, employeeName=Shiob, dateOfJoining=Tue Jun 12 00:00:00 IST 1984, salary=250000, employeeAddress=Address [employeeId=10, employeeAddress=Hydrabad]]

Employee [employeeId=20, employeeName=Himanshu, dateOfJoining=Wed Jun 14 00:00:00 IST 2000, salary=50000, employeeAddress=Address [employeeId=20, employeeAddress=Indore]]

Employee [employeeId=30, employeeName=Gagan, dateOfJoining=Wed Jun 30 00:00:00 IST 1982, salary=15000, employeeAddress=Address [employeeId=30, employeeAddress=UK]]

#######################################  soring by comparator by Address another way ###############################################

true

false

Thread[Thread-0,5,main]

Thread[Thread-1,5,main]

Thread[Thread-2,5,main]

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