Heba:
You need to override the toString method for your Objects in your
Object Class, for example something like the following:
@Override
public String toString() {
String a = this.name + " is " + Integer.toString(this.age) + "
years of age.";
return a;
}
where name represents the name in your Object and age represents the
age stored in your object.
Jeffrey
On Nov 28, 8:26 pm, Heba Samy <[EMAIL PROTECTED]> wrote:
> Hey All,
> I have a problem wz the homework of lab 1016 (Collections Framework)
> It throws exceptions when i create a TreeSet and LinkedHashSet from the array
> of diffrent abject types(Integer, String,object of MyOwnClass ) bec. TreeSet
> and LinkedHashSet sorts the elements inside them so when trying to do so,
> they cant compare diffrent objects(integer and String forexample)!!!
> thats how i understood the problem and it may be wrong...
>
> So, here is the exception it throws:
> Me
> 1
> 2
> [EMAIL PROTECTED]
> 3
> You
> [EMAIL PROTECTED]
> Exception in thread "main" java.lang.ClassCastException:
> mycollectionproject.MyOwnClass cannot be cast to java.lang.Comparable
> at java.util.TreeMap.put(TreeMap.java:542)
> at java.util.TreeSet.add(TreeSet.java:238)
> at mycollectionproject.UtilityClass.Display(UtilityClass.java:18)
> at mycollectionproject.Main.main(Main.java:58)
> Java Result: 1
> As Shown it works well with just the HashSet then throws the exceptions..
>
> And Thats also the code if u wanna check it:
> -----------------------------------------------------------------------------------
> UtilityClass
> --------------------------------------------------------------------------------
> package mycollectionproject;
> import java.util.Set;
> import java.util.Iterator;
>
> public class UtilityClass {
> public static void Display(Set s, Object[] objects){
> for (int i = 0 ; i < objects.length ; i++){
> s.add(objects[i]);
> }
> for(Iterator it = s.iterator();it.hasNext();){
> System.out.println(it.next());
> }
> }
>
> }
>
> --------------------------------------------------------
> the Main
> ------------------------------------------------
> package mycollectionproject;
> import java.util.HashSet;
> import java.util.Set;
> import java.util.TreeSet;
> import java.util.Iterator;
> import java.util.LinkedHashSet;
>
> class MyOwnClass{
> String name = " ";
> int age = 0;
> public MyOwnClass(String name,int age){
> this.name = name;
> this.age = age;
> }}
>
> public class Main {
> public static void main(String[] args) {
> // Create HashSet Object
> String me = new String ("Me");
> String u = new String("You");
> MyOwnClass o1 = new MyOwnClass("Heba",21);
> MyOwnClass o2 = new MyOwnClass("Mostafa",18);
> Integer one = new Integer(1);
> Integer two = new Integer(2);
> Integer three = new Integer(3);
> Object objects[] = {
> me,
> u,
> o1,
> o2,
> one,
> two,
> three
> };
> Set s = new HashSet();
> UtilityClass.Display(s,objects);
> s = new TreeSet();
> UtilityClass.Display(s,objects);
> s = new LinkedHashSet();
> UtilityClass.Display(s,objects);
> }
>
> }
>
> So, how can i solve this????
> Any Help would be Appreciated
> Thanks in advance,
> Heba
--~--~---------~--~----~------------~-------~--~----~
To post to this group, send email to [email protected]
To unsubscribe from this group, send email to [EMAIL PROTECTED]
For more options, visit this group at
http://groups.google.com/group/javaprogrammingwithpassion?hl=en
-~----------~----~----~----~------~----~------~--~---
