RE: Sorting of array lists

[Rikesh Balan Krishnan]

But all this methods are applicable only if the model class extends the
comparator interface.I too had a similar problem,but I was not able to
use the collection.sort because if the model class doesn't extend the
comparator interface, it will give a class cast exception.finally I had
to settle for a alofrithm where I wrote a sort method.I'm still looking
for some different method.



-----Original Message-----
From: Mark Benussi [mailto:[EMAIL PROTECTED] 
Sent: Thursday, March 10, 2005 2:39 PM
To: 'Struts Users Mailing List'
Subject: RE: Sorting of array lists

Krishna,

The below example uses a comparator which orders a collection of objects
based on a property. You can make the criteria more complicated if you
wish.

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;

public class Test {

        public static void main(String[] args) {
                Test test = new Test();
        }
        public Test() {
                ArrayList arrayList = new ArrayList();
                // The plan would have probably been read and populated
from
the db
                arrayList.add(new Plan());
                arrayList.add(new Plan());
                arrayList.add(new Plan());

                Collections.sort(arrayList, new Comparator() {
                        public int compare(Object object1, Object
object2) {
                                return ((Plan)
object1).getTitle().compareTo(
                                        ((Plan) object2).getTitle());
                        }
                });
        }

        private class Plan {
                private String name = null;
                private String title = null;
                private String description = null;
                public String getDescription() {
                        return description;
                }
                public String getName() {
                        return name;
                }
                public String getTitle() {
                        return title;
                }
                public void setDescription(String string) {
                        description = string;
                }
                public void setName(String string) {
                        name = string;
                }
                public void setTitle(String string) {
                        title = string;
                }
        }
}

-----Original Message-----
From: Krishna Mohan Radhakrishnan [mailto:[EMAIL PROTECTED] 
Sent: 10 March 2005 08:35
To: Struts Users Mailing List
Subject: Sorting of array lists


Hi all,

I have a doubt regarding sorting in array List.

I have an array List  which contains array list objects of type Plan.

The Plan object contains 3 variables : plantitle ,plandescription and
planname.

I have to sort the arraylist based on the plantitle first and then based
on the plandescription.


ArrayList list = new ArrayList();
Plan planobj = null;
For (i= 1, i<=100, i++){
planObj = readPlanObjectFromDB();
list.add(planObj);

}

//?? Now how to sort it 


Private Plan readPlanObjectFromDB(){
//queries the database to return plan object

return plan;
}

I am totally confused. Even if use bubble sorting it will cause a lot of
performance issues.

Could any one please suggest me a good method?

Regards,
Krishna Mohan


---------------------------------------------------------------------
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]


---------------------------------------------------------------------
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]


---------------------------------------------------------------------
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]