检查IllegalStateException的正确使用？

Question

以下是CompleteGraph的代码，它基本上接受节点列表，然后接收所有节点的邻接/边缘。有一个名为getAdj的函数会抛出IllegalState，因为根据逻辑，图形仍在构建中，并且即使在用户完全构造之前，use也调用了此函数。这是否是使用IllegalState的正确决定？

public class CompleteGraph<T> {

    private final Map<T, HashMap<T, Double>> graph;
    private Set<T> nodes;

    public CompleteGraph() {
        graph = new HashMap<T, HashMap<T, Double>>();
    } 

    public void addNodes (Set<T> nodes) {
        if (nodes == null) throw new NullPointerException("The node cannot be null.");
        if (nodes.size() == 0) throw new NullPointerException("The size of node cannot be zero.");
        this.nodes = nodes;
    }

    public void addEdges (T nodeId, Map<T, Double> addEdges) {
        if (!nodes.contains(nodeId)) throw new NoSuchElementException("The source node: " + nodeId +  " does not exist.");

        for (T node : addEdges.keySet()) {
            if (!nodes.contains(node)) throw new NoSuchElementException("The target node: " + nodeId + "  not exist.");
        }

        graph.put(nodeId, (HashMap<T, Double>) addEdges);
    }

    public Map<T, Double> getAdj (T nodeId) {
        if (!nodes.contains(nodeId)) throw new NoSuchElementException("The node " + nodeId + " does not exist.");
        if (!graph.containsKey(nodeId)) throw new IllegalStateException("The graph is not populated with " + nodeId); 

        return graph.get(nodeId);
    }
}