how to remove object of perticular class from ArrayList..?

[santhosh.R gowda]

Dear all,
I have Three classes p1,p2,p3 and i had object for that perticular class's

I had arraylist in which it stores all the objects of three different classes and i want to remove the objects of p3 in that arraylist with in one statement .and i had one clue that removeAll() method in collection which takes collection as its parameter.please give me a hand for this problem

[Ranveer K Kumar]

santhosh.R gowda wrote:Dear all,
I have Three classes p1,p2,p3 and i had object for that perticular class's

I had arraylist in which it stores all the objects of three different classes and i want to remove the objects of p3 in that arraylist with in one statement .and i had one clue that removeAll() method in collection which takes collection as its parameter.please give me a hand for this problem

you can use remove method
like

arraylist.remove(objectName);
or
arraylist.remove(int value);

[santhosh.R gowda]

but we have to check it through the loop i want to remove at once

[Ranveer K Kumar]

santhosh.R gowda wrote:but we have to check it through the loop i want to remove at once

use

arraylist.size() 

and if match found break the loop

[santhosh.R gowda]

and if match found break the loop

Please understand the problem correctly i must not use loop ok

[Ranveer K Kumar]

santhosh.R gowda wrote:

and if match found break the loop

Please understand the problem correctly i must not use loop ok

Dear Gowda,

My first post was without loop.
Its not matter you are using loop or without loop.

Please not confused.
for example..

        Object ob1 = new Object();
        Object ob2 = new Object();
        Object ob3 = new Object();
        ArrayList list = new ArrayList();
        list.add(ob1);
        list.add(ob2);
        list.add(ob3);
        System.out.println(list.size() +" :before removing");
        list.remove(ob2);
        System.out.println(list.size() +" :after removing");

[santhosh.R gowda]

Dear Ranveer K Kumar

You are removing only one object of perticular class see if you are having so many object of perticular class if i remove one object it should remove all the objects of that class from list

[Maneesh Godbole]

Check out ArrayList#removeAll(Collection<?> c)

Also, please read http://faq.javaranch.com/java/ShowSomeEffort
If you had checked the API after being told of the remove method, I am sure you would have found the removeAll yourself.

[santhosh.R gowda]

Example let P,Q and S are the classes
p1,p2,p3 are the objects of P
q1,q2,q3 are the objects of Q
s1,s2,s3 are the objects of S

List list = new ArrayList();
list.add(p1);
list.add(p2);
list.add(p3);
list.add(q1);
list.add(q2);
list.add(q3);
list.add(s1);
list.add(s2);
list.add(s3);

please remove 'S' objects in that list with out iterating it dont use getClass() and getInstance() method

[Maneesh Godbole]

Pseudo code:
1) Create a sublist for all 'S' Objects.
2) Use the removeAll method on the main list using this sublist.

[santhosh.R gowda]

No sir actually i had gone for interview they asked me to not sublist and they had given me the clue that use removeAll method thats all

[Ranveer K Kumar]

This case best way to use generic to add the object in the list.
In above example if you are using n no. of objects then how will you remove without iterating. the best way to use is loop..
If you are able to remove then use
list.remove(int)
if you know the best way then let me know...

[Ranveer K Kumar]

this is tricky Q and atleast my knowledge removeAll will remove all the particular Collection(object) from list, and sublist not to be used so
collection cannot be passed.
I am agree with Maneesh, but also sublist not to be used, loop is already not to used..
then only way that remove mannually one by one...

But the main thing I am not sure about the other methods to solve this problem...Please let me know
if any other solution availabe..
Thanks

[Christophe Verré]

list.removeAll(new ArrayList(list.subList(list.size()-3, list.size())));

Or even better answer :

This code is wrong because the next letter after Q is R

[santhosh.R gowda]

  list.removeAll(java.util.collections.SingletonList(Object o))  

[Christophe Verré]

It's not the answer, is it ? Because singleList doesn't accomplish what you are trying to do.