Question

I had to subclass ResourceBundle due to our specific needs.

However, to override getKeys(), I am a bit in trouble. This getKeys needs to somehow concatenate from a map of underlying ResourceBundles. How can I do that?

Thanks

EDIT: While submitting I came across an idea. Basically we have for each of our Module a ResourceBundle, so my code looks like this so far:

public Enumeration<String> getKeys() {
        ArrayList<String> keys = new ArrayList<String>();

        for (Map.Entry<Module, ResourceBundle> entry : internalMap.entrySet()) {
            Enumeration<String> tmp = entry.getValue().getKeys();
            while (tmp.hasMoreElements()) {
                String key = tmp.nextElement();
                keys.add(key);
            }
        }

        return Collections.enumeration(keys);
    }

Answer 1

This is what we finally came up with. There is more code to it but thought it would be fair to share the basics. The solution follows a bit skaffman’s proposal.
Thanks to all contributions.

public class ChainedResourceBundle extends ResourceBundle implements Enumeration<String> {

    Iterator<Map.Entry<Module, ResourceBundle>> tables;
    private Enumeration<String>                 keys;

    private Map<Module, ResourceBundle>         internalMap    = new HashMap<Module, ResourceBundle>();
    private Map<String, String>                 customizedKeys = new HashMap<String, String>();


    @Override
    public Enumeration<String> getKeys() {
        tables = internalMap.entrySet().iterator();
        nextTable();
        return this;
    }


    @Override
    public boolean hasMoreElements() {
        return keys != null;
    }


    @Override
    public String nextElement() {
        String key = keys.nextElement();
        if (!keys.hasMoreElements()) {
            nextTable();
        }
        return key;
    }

    private void nextTable() {
        if (tables.hasNext()) {
            keys = tables.next().getValue().getKeys();
        } else {
            keys = null;
        }
    }

}