private void createChildMap(final List<ExplorerNode> explorerNodes,
                                final Map<ExplorerNode, List<ExplorerNode>> childMap) {
        explorerNodes.forEach(explorerNode -> {
            final List<ExplorerNode> children = explorerNodeService.getChildren(explorerNode.getDocRef());
            if (NullSafe.hasItems(children)) {
                childMap.put(explorerNode, children);
                createChildMap(children, childMap);
            }
        });
    }
Create a map of folders and their child items.
stroom-explorer/stroom-explorer-impl/src/main/java/stroom/explorer/impl/ExplorerServiceImpl.java