java - 检查节点是否已在图中的优雅方法

Question

我想检查具有特定 ID 的节点是否已存在于我的图中，或者我是否必须创建一个新对象。目前我正在使用以下代码执行此操作:

// at this point I have the attributes for the node I need

String id = getIdOfNeededNode(); // The id is used to search for the node in the graph

// now I have to search for the node in the graph
Node node = new Node("dummy_id"); // This is the line I don't like; 
                                  // I would prefer not to have a dummy node
                                  // but the compiler will then complain that the node might not be initialized 

boolean alreadyCreated = false;

for(Node r : graph.getVertices()){ // search for the node with this id in the graph
    if (r.getId().equals(portId)){
        node = r;
        alreadyCreated = true;
        break;
        }
    }

if (!alreadyCreated) {     // create a new object if the node was not found
    node = new Resource(portId);
    createdPortResources.add(port);
    }

// In the remainder of the program, I am working with the node object which then is in the graph

事实上，我正在创建一个只是占位符的虚拟节点，这真的很难看。请让我知道如何以更优雅的方式解决这个问题。

Answer 1

好吧，你可以这样做 Node node = null;

但一般来说，只需保留从 portId 到节点的映射即可。
当您想要进行检查时，只需查阅该 map 即可。
这将变得更加容易和快捷。