java - 执行 Java 8 内部流的实例

Question

我如何做 Java 8 内部流的实例

for (List<Category> parentPath : getPathsInternal(parent, controlSet)) {
  if (!(parentPath instanceof LinkedList)) {
    parentPath = new LinkedList<Category>(parentPath);
  }
  parentPath.add(category);
  result.add(parentPath);
}

我不知道如何在 Java 8 流中编写这样的函数。有什么指示吗？

if (!(parentPath instanceof LinkedList)) {
    parentPath = new LinkedList<Category>(parentPath);
  }

Answer 1

getPathsInternal(parent, controlSet).stream()
   .map(parentPath -> 
       (parentPath instanceof LinkedList) 
           ? parentPath : new LinkedList<>(parentPath))
   .peek(parentPath -> parentPath.add(category))
   .collect(toList()); // or whatever result is