Sorting of list of objects based on multiple parameter

Question

I have a List of Objects List<Student>.

class Student {
 private String name;
 private Integer age;
 private Integer rank

 public String getName() {
  return this.name;
 }
 public void setName(String name) {
  this.name = name;
 }
 public Integer getAge() {
  return this.name;
 }
 public void setAge(Integer age) {
  this.age = age;
 }
 public Integer getRank() {
  return this.rank;
 }
 public void getRank(Integer rank) {
  this.rank = rank;
 }
}

I have to sort List based on rank first, if two students have same rank then based on their age and if their age is same then based on their name.

Can any one help? Thanks

Either create a Comparator<Student, Student> or have Student implement Comparable<Student> and then define your comparison logic in there. Either way, you can then use Java's builtin sorting capabilities. — CollinD
– CollinD, Commented May 27, 2017 at 17:26

D. Peter · Accepted Answer · 2017-05-27 18:06:47Z

1

You can use java8 lambdas

List<Student> students = new Arraylist<>();
...
...
...
student.sort()

students.sort(Comparator.comparing(Student::getName).thenComparing(Student::getAge));

edited May 27, 2017 at 18:06

answered May 27, 2017 at 17:30

D. Peter

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1 Comment

ADS Over a year ago

I suppose you mean Java8 since lamdas introduced in Java8 and Student::getName is illegal in Java7

Neeraj Jain · Accepted Answer · 2017-05-27 17:28:43Z

0

In java8 you have .thenComparing(...) method

Comparator< Student> studentComparator = Comparator.comparing(student -> student.name);
comparator = comparator.thenComparing(Comparator.comparing(student -> student.age));
comparator = comparator.thenComparing(Comparator.comparing(student -> student.rank));

 // Then pass this comparator in Collections#sort method

Collecions.sort(studentList, studentComparator); Your list will be sorted

answered May 27, 2017 at 17:28

Neeraj Jain

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Comments

Sohi · Accepted Answer · 2017-06-01 08:57:22Z

0

You can use Guava for Java 7 for same use case .

See: https://github.com/google/guava/wiki/CommonObjectUtilitiesExplained#compare/compareTo.md

answered Jun 1, 2017 at 8:57

Sohi

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