比较器不让我比较 T 值

Question

>Intellij的想法在尝试比较两个T值时在类internalNode中给了我这个错误：compare（capture，capture）不能应用于（T，T）。我不明白为什么。我已经将参数化类型更改为 T，它仍然向我显示消息，但不是只捕获 T。任何帮助都非常感谢

public class BSpecialTree<T> {
private Node<T> root;
private int keysNumber;
private Comparator<? super T> cmp;
public BSpecialTree(Comparator<? super T> cmp, int keysNumber) {
    this.cmp = cmp;
    this.keysNumber = keysNumber;
}
public boolean belongs(T key) {
    if(key == null) {
        if(root == null)
            return true;
        return false;
    }
    return root.belongs(key);
}
private interface Node<T> {
    boolean belongs(T key);
}
private class internalNode<T> implements Node<T> { 
    private T key;
    private Node<T> left, right;
    public internalNode(T key) {
        this.key = key;
    }
    public boolean belongs(T key) {
        if(cmp.compare(this.key, key) > 0) //ERROR
            return left.belongs(key);
        return right.belongs(key);
    }
}
private class leafNode<T> implements Node<T> {
    private List<T> keys;
    public leafNode() {
        keys = new ArrayList<T>(keysNumber);
    }
    public boolean belongs(T key) {
        return keys.indexOf(key) != -1;
    }
}

Answer 1

您的内部类正在引入自己的泛型类型<T>，该泛型类型对BSpecialTree<T>隐藏<T>，但比较器被声明为使用来自BSpecialTree的T，而不是来自internalNode。

也许尝试

private class internalNode implements Node<T> {
//                        ^remove `<T>` from here