Store a linked list into a file

[Joe Schaffer]

Hi everybody,
I have the following problem. I have an object (Userclass user) that contains another object (Linkclass linklist). The object linklist contains a linked list with a dynamic amount of links.
How can I store all the data into a file by just saving the user object? If I save the user object, I think the file wouldn't contain the linklist objects?
Thank you for your help
Joe

[William Brogden]

If all the objects involved implement Serializable, you should be able to write the whole user object with the collection in a single call. Try it and see.
Bill

[Joe Schaffer]

Thanks Bill.
I added "implements Serializable" to every class included in my object.
These two functions do my serialization:

 
private static void WriteToFile(UserInformation user){
  try {
    FileOutputStream fos = new FileOutputStream ("keep.dat");
    ObjectOutputStream oos = new ObjectOutputStream(fos);
    oos.writeObject(user);
    fos.close();
  } 
  catch (Exception e) {
    System.out.println(e);   
  }
}
private static UserInformation ReadFromFile(){
  UserInformation o_userdata = new UserInformation();
  try {
    FileInputStream fis = new  FileInputStream("keep.dat");
    ObjectInputStream ois = new ObjectInputStream(fis);
    Object obj = ois.readObject();
    o_userdata = (UserInformation) obj;
  } 
  catch (Exception e) {
    System.out.println(e);
  } 
  return o_userdata;
} 

Works perfect!