I will advise you to use unowned relation in this scnerio. Instead of
Directory entity having childrens...i will put parent information in the
Directory entity.. this way you can make sure one Directiry can have
millions of Child directory...as you will not max out the maximum entity
size.
class Directory {
public String name;
public ArrayList<Directory> children = new
ArrayList<Directory>();//Delete this
public Key parentKey;
// could have any other properties or attributes here as well
Directory(String n){
name = n;
public void Display() {
System.out.println(" name: " + name);
for(Directory d : children)
Display();
}
}
You can write one GWT RPC function like this
Directory[] getMyChildren(String parentKeyParam){
//On the server you can query like this
Select * from Directory where parentKey = parentKeyParam
and return it back to GWT.
}
On Wed, May 4, 2011 at 3:47 AM, RH <richkh...@gmail.com> wrote:
> here would be an example using the heap:
>
> class Directory {
> public String name;
> public ArrayList<Directory> children = new ArrayList<Directory>();
>
> // could have any other properties or attributes here as well
> Directory(String n){
> name = n;
>
> public void Display() {
> System.out.println(" name: " + name);
> for(Directory d : children)
> Display();
> }
> }
>
> You should be able to add or remove any object in the tree:
>
> ...
> directoryObject.children.Add(new Directory("new child"));
> ...
>
> and you can display the node and any child nodes:
>
> ...
>
> directoryObject.Display();
>
> I want to use the GAE datastore to persist these POJOs (easy enough in
> JDO) but also maintain their structural relationship to each other
> (hard, at least that I can see) - That is, I am trying to persist the
> object instances *and* their relations to each other.
>
> RH
>
>
>
> On May 2, 11:37 am, Todd Vierling <t...@duh.org> wrote:
> > On Saturday, April 30, 2011 9:06:45 PM UTC-4, RH wrote:
> >
> > > I'm looking for a simple way to persist a set of dynamic Composite
> > > Design Pattern objects (as described in Design Patterns by Gamma,
> > > Helm, Johnson, and Vlissides) with either Google's native datastore,
> > > JDO, or JPA, as well as send to and from the client via RPC.
> >
> > Design patterns mean pretty much zero in real-world discussions, so
> example
> > code would be a lot more helpful. (Or in other words, "what does the
> class
> > you're trying to persist look like?")
>
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