import com.google.javascript.jscomp.DefinitionsRemover.UnknownDefinition; //导入依赖的package包/类
@Override
public Collection<Definition> getDefinitionsReferencedAt(Node useSite) {
  List<Name> nameRefs = getReferencesAt(useSite);
  if (nameRefs.isEmpty()) {
    return null;
  }

  List<Definition> result = Lists.newArrayList();
  for (Name nameRef : nameRefs) {
    List<Definition> decls = nameRef.getDeclarations();
    if (!decls.isEmpty()) {
      result.addAll(decls);
    } else {
      result.add(new UnknownDefinition(useSite));
    }
  }

  if (!result.isEmpty()) {
    return result;
  } else {
    return null;
  }
}
 

import com.google.javascript.jscomp.DefinitionsRemover.UnknownDefinition; //导入依赖的package包/类
private void visitExterns(NodeTraversal traversal, Node node) {
  if (node.getJSDocInfo() != null) {
    for (Node typeRoot : node.getJSDocInfo().getTypeNodes()) {
      traversal.traverse(typeRoot);
    }
  }

  Definition definition = DefinitionsRemover.getDefinition(node, true);
  if (definition != null) {
    String name = definition.getSimplifiedName();
    if (name != null) {
      Node rValue = definition.getRValue();
      if ((rValue != null) && !NodeUtil.isImmutableValue(rValue) && !rValue.isFunction()) {
        // Unhandled complex expression
        Definition unknownDefinition = new UnknownDefinition(definition.getLValue(), true);
        definition = unknownDefinition;
      }
      addDefinition(name, definition, node, traversal);
    }
  }
}