[SOLVED] A better way to do this - ArrayLists

[Tshegofatsom]

public java.util.List<com.netcb.sas.adapters.gms.Town> getTowns() {
ArrayList<Town> towns = new ArrayList<Town>();
Town town = new Town();
try{
java.util.Iterator locations = new DBUtil().getTowns().iterator();
while(locations.hasNext()){
Location loc = (Location)locations.next();
town.setId(loc.getNoLocation());
town.setName(loc.getDescLocation());
towns.add(town);
}
return towns;
}
catch(HibernateException he){
he.printStackTrace();
}
catch(Exception e){
e.printStackTrace();
}
//todo
return null;

Town and Location are my own defined classes but not related. Is there a way to achieve the same results without a loop or without

town.setId(loc.getNoLocation());
town.setName(loc.getDescLocation());

Is there a better way to do this?

[OrangeDog]

Collections.copy()?

[Tshegofatsom]

The classes Town and Location are not related so I don't think Collections.copy() will do the trick.

[Tolls]

Town and Location are my own defined classes but not related. Is there a way to achieve the same results without a loop or without
Is there a better way to do this?

All this is doing:

town.setId(loc.getNoLocation());
town.setName(loc.getDescLocation());

is setting the id and name of the same town, over and over again. So all the items in ArrayList will be exactly the same object, and consequently have exactly the same data in them.

[RamyaSivakanth]

Hi,
If the objects are related we can do.But,Location is a separate class object and Town is a separate class object.How can u copy directly?

-Regards
Ramya

[Tshegofatsom]

That is exactly my question buddy. How can we copy exactly? Is there a way?

[Tolls]

That is exactly my question buddy. How can we copy exactly? Is there a way?

I'm a bit confused as to what you expect could happen here?

Apart from the bug I pointed out earlier, that is.

You have a list of objects, which you want to turn into a list of other objects on a one-to-one basis, so there's got to be a loop somewhere.

[RamyaSivakanth]

As Toll said,it is not possible.

Take a Hashtable and load the values from location and return it to Townclass.Here also u need to iterate.No other go........

[Tshegofatsom]

The bug isn't really a bug,it does not really matter. I just wanted to know
1. If the same goal can be achieved using a logic that saves resources
2. If we still need to loop, can we at least be able to assign a loc to a town? ie

town = loc;

If I was using c++, i would overload the operator "=" to accept a type of Location and do the "one-to-one basis" in there. In that way I can assign an object of Location to Town whenever I want to i;e

town = loc;

[Tolls]

The bug isn't really a bug,it does not really matter. I just wanted to know
1. If the same goal can be achieved using a logic that saves resources
2. If we still need to loop, can we at least be able to assign a loc to a town? ie

If I was using c++, i would overload the operator "=" to accept a type of Location and do the "one-to-one basis" in there. In that way I can assign an object of Location to Town whenever I want to i;e

Well, the closest to that would be a constructor in Town that accepts a Location, in which you then do the assignments you are currently doing.

But that bit I pointed out is still a bug...even in test code...:)

[Tshegofatsom]

Well, the closest to that would be a constructor in Town that accepts a Location, in which you then do the assignments you are currently doing.

Yeah that is good.... I think that will work for me since I cant overload the "=" operator
in JAVA.

But that bit I pointed out is still a bug...even in test code...

Ok if its a concern then all needs to be done is to create a new town in every iteration in the loop.....That should work :)

But the constructor solution is sure the closest (Unless someone has some thing else) I like that......I give you raps for that... "viva Tolls viva!!"

[Tolls]

Yeah that is good.... I think that will work for me since I cant overload the "=" operator
in JAVA.


Ok if its a concern then all needs to be done is to create a new town in every iteration in the loop.....That should work :)

But the constructor solution is sure the closest (Unless someone has some thing else) I like that......I give you raps for that... "viva Tolls viva!!"

If you do this via a constructor, you'll be creating a new Town each time anyway, and I can rest happy in the knowledge there's one less bug in the world...:)

[RamyaSivakanth]

Hi,
As Toll Suggested,I think you can do like this..

In Townclass u will have constructor
public Town(String id, String name) {
}
then have something in the iterator loop like

public java.util.List<com.netcb.sas.adapters.gms.Town> getTowns() {
ArrayList<Town> towns = new ArrayList<Town>();
//Town town = new Town();[COLOR="Red"][/COLOR]
try{
java.util.Iterator locations = new DBUtil().getTowns().iterator(); 
while(locations.hasNext()){
Location loc = (Location)locations.next();
[COLOR="red"]//town.setId(loc.getNoLocation());
//town.setName(loc.getDescLocation());[/COLOR]
//The above block u can remove and instead u can do like this below

//[COLOR="red"]towns.add(town);[/COLOR]
//U can add this in a single line.
towns.add(new Town(loc.getNoLocation(), loc.getDescLocation);

}
return towns;
}

towns.add(new Town(loc.getNoLocation(), loc.getDescLocation);

[Tolls]

Hi,
As Toll Suggested,I think you can do like this..

In Townclass u will have constructor
public Town(String id, String name) {
}

Well, I was thinking more of

public Town (Location loc) { // Do assignment stuff here
}

but that depends on whether Town and Location will always be distributed together.