How to get values from each TreeItem checkboxes(GWT)?

I am developing a GWT app. I have some TreeItems with checkbox(rootCheckBox) which store GwtDomain objects and inside of TreeItems more items with checkBoxes(childTreeItemCheckBox) which are GwtActions. But I don't know how to get values from each TreeItem specifically. I write some code with tho HashMaps:rootCheckBoxMapList which collects values from rootCheckBox and childCheckBoxMapList which collects values from childTreeItemCheckBoxes. But this childCheckBoxMapList gives me the list of all selected childTreeItemCheckBoxes, but I want to sort that for every selected rootCheckBox I have list of selected childTreeItemCheckobex from that TreeItem specifically ,not from all TreeItems. This is my code:

 GWT_DOMAIN_SERVICE.findAll(new AsyncCallback<List<GwtDomain>>() {

            @Override
            public void onFailure(Throwable caught) {
                exitMessage = MSGS.dialogAddPermissionErrorDomains(caught.getLocalizedMessage());
                exitStatus = false;
                hide();
            }

            @Override
            public void onSuccess(List<GwtDomain> result) {

                for (final GwtDomain gwtDomain : result) {
                    GWT_DOMAIN_SERVICE.findActionsByDomainName(gwtDomain.name(), new AsyncCallback<List<GwtAction>>() {

                        @Override
                        public void onFailure(Throwable caught) {
                            exitMessage = MSGS.dialogAddPermissionErrorActions(caught.getLocalizedMessage());
                            exitStatus = false;
                            hide();
                        }

                        @Override
                        public void onSuccess(List<GwtAction> result) {
                            rootCheckBox = new CheckBox();
                            rootCheckBox.setBoxLabel(gwtDomain.toString());
                            rootTreeItem = new TreeItem(rootCheckBox);
                            for (final GwtAction gwtAction : result) {

                                final CheckBox childTreeItemCheckox = new CheckBox();
                                treeItem = new TreeItem(childTreeItemCheckox);
                                childTreeItemCheckox.setBoxLabel(gwtAction.toString());

                                rootTreeItem.addItem(treeItem);

                                tree.addItem(rootTreeItem);
                                childTreeItemCheckox.addListener(Events.OnClick, new Listener<BaseEvent>() {

                                    @Override
                                    public void handleEvent(BaseEvent be) {

                                        childTreeItemCheckox.setValue(true);
                                        if (childTreeItemCheckox.getValue()) {
                                            childCheckBoxMapList.put(gwtAction, childTreeItemCheckox);

                                        }
                                    }
                                });

                            }

                            rootCheckBoxMapList.put(gwtDomain, rootCheckBox);

                        }

                    });

                }

            }
        });

And this is my code when I should collect checked values:

 List<GwtDomain> rootCheckBoxChecked = new ArrayList<GwtDomain>();
        List<GwtAction> childCheckBoxChecked = new ArrayList<GwtAction>();
        for (Map.Entry<GwtDomain, CheckBox> e : rootCheckBoxMapList.entrySet()) {

            if (e.getValue().getValue()) {
                rootCheckBoxChecked.add(e.getKey());
                for (Map.Entry<GwtAction, CheckBox> childCheckBox : childCheckBoxMapList.entrySet()) {
                    if (childCheckBox.getValue().getValue())
                        childCheckBoxChecked.add(childCheckBox.getKey());
                }
            }

        }

What I am doing wrong? How to set that every treeItem has list with values just from itself?