drools-eclipse/org.guvnor.eclipse.webdav/src/kernel/org/eclipse/webdav/internal/kernel/utils/NestedHashtable.java
public Enumeration keys() {
        if (defaults == null)
            return localValues.keys();
        return new MergedEnumeration(localValues.keys(), defaults.keys());
    }
public Enumeration keys() {
        if (defaults == null)
            return localValues.keys();
        return new MergedEnumeration(localValues.keys(), defaults.keys());
    }
Return an enumeration over the context's keys. (recursively computes the
keys based on keys defaults as well)

@return an enumeration over the context keys