Assign value from one set to another set

[S Majumder]

Hi All,
I have two HashSets which have 2 objects of type ClassRoom.
I want to take one HashSet's value and put into another HashSet.

Here is my approach :

//POJO 
Class ClassRoom{

Integer id;
String roomName;
Integer  roomNumber;

//getter and setter of all properties .......





public ClassRoom(Integer id, String roomName, Integer roomNumber) {
		super();
		this.id = id;
		this.roomName= roomName;
		this.roomNumber= roomNumber;
	}

	


}


class MyApp{

public static void main(String[] args) {

Set<ClassRoom> set1 = new HashSet<ClassRoom>();
		ClassRoom obj1 = new ClassRoom(1,"T1",23);
		set1.add(obj1);
		
		
		
		ClassRoom  obj2 = new ClassRoom (2,"T2",23);
		set1.add(obj2);
		
		
	
		Set<ClassRoom > set2 = new HashSet<ClassRoom >();
		
		
		ClassRoom tempobj1 = new ClassRoom (1,"TTY",34);
		set2.add(tempobj1);
		
		
		
		ClassRoom tempobj2 = new ClassRoom (2,"GF,435);
		set2.add(tempobj2);
		
		
		for(ClassRoom cr : (Set<ClassRoom >) set1 ){
			
			Iterator itarator = set2.iterator();
			
			while(itarator.hasNext()){
				
				ClassRoom bean= (ClassRoom ) itarator.next();
				
				if(cr.getId()==1 && cr.getId()==bean.getId()){
					//setting values here .....
					break;
				}
				
//same will be for the id 2 ........
				

						
			}
			
			
		}
		
		

}

}

Is this approach is good ?

It's appreciable if anyone give better approach

regards,
Satya

[Campbell Ritchie]

There are far simpler ways. You can pass the entire contents of a Set to another. I suggest you look at the methods of the Set interface, and the constructors of one of the Set implementations.

[Campbell Ritchie]

What on earth is that loop with the break; in for? Since the order of iteration of a Set is undefined, the results of that loop will be undefined and unpredictable.
You ought also to have all the fields in that Classroom class private and accessed by getXXX methods.

[S Majumder]

Ritchie ,, thanks for the reply ...Yes there are few methods by which we can put all values from one set to another .

But, question arise when I want to persist only one set of objects and do the rest of my work by that set .Then I have to put each object's data one by one to another set of object (here ClassRoom ...).

Correct me if am wrong .


Satya

[Campbell Ritchie]

You are going to have to use some sort of filter if you wish to pass some values only. Do it with an if (...) {...otherSet.add(...);} statement inside the loop. The break; will not work as you expect.

[S Majumder]

Ritchie ,
Could you give one example , am not getting you ...

Satya

[dennis deems]

Your intent isn't quite clear to me. Are you saying you are copying the attributes from the elements of one set onto the members of the second set?

[S Majumder]

Hi Dennis Deems ,
I have to persist only one set of objects , (here set1) , getting updated data from set2 and putting into set1.
I can't change the objects (here ClassRoom) into the set1.So copping all attributes from one set of objects (set2) to another set (set1).
satya