Store sessionScope java.util.TreeMap variable in a document in xPage - xpages

Question

I am working on an application where I am creating a java.util.TreeMap containing data fetched from various other documents of the application and then assigning that treemap to a sessionsScope variable. This is working fine.
Now I want to provide a functionality wherein I need to store this map inside a NotesDocument.
But when I try doing this, I am getting an error.
var doc:NotesDocument = database.createDocument();
doc.replaceItemValue("Form","testForm");
print("json = "+sessionScope.get("Chart_Map"));
doc.replaceItemValue("Calender_Map",sessionScope.get("Chart_Map"));
doc.save();
Exception:
Error while executing JavaScript action expression
Script interpreter error, line=4, col=13: [TypeError] Exception occurred calling method NotesDocument.replaceItemValue(string, java.util.TreeMap) null**
Is it possible to store a java.util.TreeMap in a notesdocument field?
If yes then how to implement that?
If no then why not? has that something to do with serializability?

Answer 1

You can't store Java objects inside Document fields unless you use the MimeDomino Document data source
http://www.openntf.org/main.nsf/blog.xsp?permaLink=NHEF-8XLA83
Or even better the new openntf Domino API that has this functionallity built in
http://www.openntf.org/main.nsf/project.xsp?r=project/OpenNTF%20Domino%20API
using MimeStorage

Answer 2

Fredrik is right, the MimeDomino makes most sense. If you are not ready and your field isn't too big for a normal Notes item, you could use CustomDataBytes as Sven suggested - or you use JSON by subclassing TreeMap. It could look like this:
import java.util.TreeMap;
import java.util.Vector;
import com.google.gson.Gson;
import com.google.gson.JsonSyntaxException;
import lotus.domino.Item;
import lotus.domino.NotesException;
public class TreeMapItem extends TreeMap<String, String> {
private static final long serialVersionUID = 1L;
public static TreeMapItem load(Item source) throws JsonSyntaxException, NotesException {
Gson g = new Gson();
TreeMapItem result = g.fromJson(source.getText(), TreeMapItem.class);
return result;
}
public void save(Item target) throws NotesException {
Gson g = new Gson();
target.setValueString(g.toJson(this));
}
}
I used Google's Gson, it is quite easy, but you might need to deploy it as plug-in for the Java security to work. There is build in JSON in XPages too - a little more work. An alternate approach would be to use 2 fields in Domino, one to load the keys from and one for the values - it would be in line with Domino practises from classic.
A third approach would be be to store the values separated using a pipe character:
#SuppressWarnings({ "unchecked", "rawtypes" })
public void saveCompact(Item target) throws NotesException {
Vector v = new Vector();
for (Map.Entry<String, String> me : this.entrySet()) {
v.add(me.getKey()+"|"+me.getValue());
}
target.setValues(v);
}
#SuppressWarnings("rawtypes")
public static TreeMapItem loadCompact(Item source) throws NotesException {
TreeMapItem result = new TreeMapItem();
Vector v = source.getValues();
for (Object o : v) {
String[] candidate = o.toString().split("|");
if (candidate.length > 1) {
result.put(candidate[0], candidate[1]);
}
}
return result;
}
Let us know how it works for you