Click here to watch in Youtube :
https://www.youtube.com/watch?v=vU1uiwOavLM&list=UUhwKlOVR041tngjerWxVccw
Employee.java
AscEmployeeIdComparator.java
https://www.youtube.com/watch?v=vU1uiwOavLM&list=UUhwKlOVR041tngjerWxVccw
Employee.java
public class Employee { private Integer employeeId; private String name; public Employee( Integer employeeId, String name ) { super(); this.employeeId = employeeId; this.name = name; } public Integer getEmployeeId() { return employeeId; } public void setEmployeeId( int employeeId ) { this.employeeId = employeeId; } public String getName() { return name; } public void setName( String name ) { this.name = name; } @Override public String toString() { return "Employee [employeeId=" + employeeId + ", name=" + name + "]"; } }
import java.util.Comparator; public class AscEmployeeIdComparator implements Comparator<Employee> { /* * This method used to order the employee objects in Ascending order based * on employeeId. */ @Override public int compare(Employee employee1, Employee employee2) { return employee1.getEmployeeId().compareTo(employee2.getEmployeeId()); } }
import java.util.ArrayList; import java.util.Collections; import java.util.Comparator; import java.util.List; /* Method public static <T> Comparator<T> reverseOrder(Comparator<T> cmp) Parameters: cmp - a comparator who's ordering is to be reversed by the returned comparator or null Returns: A comparator that imposes the reverse ordering of the specified comparator. */ public class CollectionsExample { public static void main(String[] args) { List<Employee> employeeList = new ArrayList<Employee>(); Employee john = new Employee(300, "John"); Employee david = new Employee(100, "David"); Employee peter = new Employee(200, "Peter"); Employee juli = new Employee(500, "Juli"); Employee ram = new Employee(400, "Ram"); employeeList.add(john); employeeList.add(david); employeeList.add(peter); employeeList.add(juli); employeeList.add(ram); System.out.println("Before sort the employeeList : \n"); displayEmployeeInfo(employeeList); AscEmployeeIdComparator ascEmployeeIdComparator = new AscEmployeeIdComparator(); Collections.sort(employeeList, ascEmployeeIdComparator); System.out .println("\nAfter Sort the employeeList using ascEmployeeIdComparator : \n"); displayEmployeeInfo(employeeList); /* * Returns a comparator that imposes the reverse ordering of the * specified comparator. If the specified comparator is null, this * method is equivalent to reverseOrder() (in other words, it returns a * comparator that imposes the reverse of the natural ordering on a * collection of objects that implement the Comparable interface). */ Comparator<Employee> reverseEmployeeIdcomparator = Collections .reverseOrder(ascEmployeeIdComparator); // sort the list Collections.sort(employeeList, reverseEmployeeIdcomparator); System.out .println("\nAfter Sort the employeeList using reverseEmployeeIdcomparator : \n"); displayEmployeeInfo(employeeList); } private static void displayEmployeeInfo(List<Employee> employeeList) { for (Employee employee : employeeList) { System.out.println("ID :" + employee.getEmployeeId() + " Name :" + employee.getName()); } } }
Before sort the employeeList : ID :300 Name :John ID :100 Name :David ID :200 Name :Peter ID :500 Name :Juli ID :400 Name :Ram After Sort the employeeList using ascEmployeeIdComparator : ID :100 Name :David ID :200 Name :Peter ID :300 Name :John ID :400 Name :Ram ID :500 Name :Juli After Sort the employeeList using reverseEmployeeIdcomparator : ID :500 Name :Juli ID :400 Name :Ram ID :300 Name :John ID :200 Name :Peter ID :100 Name :David
https://sites.google.com/site/javaee4321/java-collections/CollectionsDemo-ReverseOrderComparator.zip?attredirects=0&d=1
See also:
No comments:
Post a Comment