How to sort a vector elements that contains the user define
class object? (Note: If Suppose consider, A Student class
contain two data members. They are String studentName and
int rollNo. I am creating Four objects for this class, each
object contains students details like name and roll no. Now
i am storing that objects in vector and if i retiving the
elements from the vector means then it should be display in
sorting order)
Answer Posted / naren reddy
For sorting Any user defined class,We need to implement the
userdefined class with comparable or comparator
interfcae.Then only your collections.sort(ArrayList al)
will work,Otherwise it won't work.
Ex: class Employee implements Comparable{
private int age;
public void setAge(int age){
this.age=age;
}
public int getAge(){
return this.age;
}public int compareTo(Object otherEmployee){
/*
If passed object is of type other than Employee,
throw ClassCastException.
*/
if(!(otherEmployee instanceof Employee)){
throw new ClassCastException("Invalid object");
}
int age = ((Employee) otherEmployee).getAge();
if(this.getAge() > age)
return 1;
else if ( this.getAge() < age )
return -1;
else
return 0;
}
}
| Is This Answer Correct ? | 2 Yes | 0 No |
Post New Answer View All Answers
Can we sort a map in java?
What is the class in java?
placement papaers of spring computing technology
What is deserialization?
What is scope of a variable?
What is null in java?
Why stringbuilder is not thread safe?
How to display names of all components in a Container?
Can an interface have a constructor?
What is a ternary operator in java? What is an interface?
What do u mean by variable?
how do I create a runnable with inheritance? : Java thread
What is the program development process?
How do you start a new line in java?
What is arrays aslist in java?