Java - handling hierarchies

Question

Hello: I have an app where in a thread hierarchy (persisted entity) is modelled as follows (note that this could be a deeply nested hierarchy):

Thread
{
    private key;
    private rootKey;
    private parentKey;


.. getters ..
.. setters ..
}

I have a DTO which has the following structure

ThreadDTO
{
    private key;
    private rootKey;
    private parentKey;

    ArrayList<ThreadDTO> childThreads;

... getters ...
... setters ...
}

I would like to convert the entity instances into the DTO. Are there any standard algorithms / best practices available that can be optimally be used for doing this transformation ? Any feedback would be appreciated..

Answer 1

DTO are quite annoying, the best thing you can do with them is to create a method which takes a Thread in parameter and copy the attributes, and another which will return a Thread with a copy of the attributes.

An other solution from Adam Bien is the Generic DTO, there is less security but also less copy/paste of in code.