private void validateTree()

in stetho/src/main/java/com/facebook/stetho/inspector/elements/ShadowDocument.java [391:447]
43 lines of code
11 McCabe index (conditional complexity)

    private void validateTree(Map<Object, ElementInfo> elementToInfoMap) {
      // We need a tree, not a forest.
      HashSet<Object> rootElements = new HashSet<>();

      for (Map.Entry<Object, ElementInfo> entry : elementToInfoMap.entrySet()) {
        final Object element = entry.getKey();
        final ElementInfo elementInfo = entry.getValue();

        if (element != elementInfo.element) {
          // should not be possible
          throw new IllegalStateException("element != elementInfo.element");
        }

        // Verify children
        for (int i = 0, N = elementInfo.children.size(); i < N; ++i) {
          final Object childElement = elementInfo.children.get(i);
          final ElementInfo childElementInfo = elementToInfoMap.get(childElement);

          if (childElementInfo == null) {
            throw new IllegalStateException(String.format(
                "elementInfo.get(elementInfo.children.get(%s)) == null",
                i));
          }

          if (childElementInfo.parentElement != element) {
            throw new IllegalStateException("childElementInfo.parentElement != element");
          }
        }

        // Verify parent
        if (elementInfo.parentElement == null) {
          rootElements.add(element);
        } else {
          final ElementInfo parentElementInfo = elementToInfoMap.get(elementInfo.parentElement);
          if (parentElementInfo == null) {
            throw new IllegalStateException(
                "elementToInfoMap.get(elementInfo.parentElementInfo) == NULL");
          }

          if (elementInfo.parentElement != parentElementInfo.element) {
            // should not be possible
            throw new IllegalStateException(
                "elementInfo.parentElementInfo != parentElementInfo.parent");
          }

          if (!parentElementInfo.children.contains(element)) {
            throw new IllegalStateException(
                "parentElementInfo.children.contains(element) == FALSE");
          }
        }
      }

      if (rootElements.size() != 1) {
        throw new IllegalStateException(
            "elementToInfoMap is a forest, not a tree. rootElements.size() != 1");
      }
    }