java – 如何获得一个内部类继承包围类的通用类型？

>删除< T>来自TSTNode的类型参数(即使其成为非泛型) – 它仍然可以访问外部< T>.
>重命名< T>类TSTNode中的类型参数(说)U.

[UPDATE]

以下是重写代码的四种不同的方法.他们都编译我想你应该考虑使用EnumMap(见下面的第4版).

版本1：在内部类中使用不同命名的类型参数.您需要使用List而不是数组.

public class TernarySearchTree<T> {

    protected class TSTNode<U> {
      // index values for accessing relatives array:
      protected static final int PARENT = 0,HIKID = 3;

      protected char splitchar;
      protected List<TSTNode<U>> relatives;
      private U data;

      protected TSTNode(char splitchar,TSTNode<U> parent) {
        this.splitchar = splitchar;
        relatives = new ArrayList<TSTNode<U>>();
        for (int i = 0; i < HIKID; ++i) {  // Allocate 4 slots in relatives
          relatives.add(null);
        }
        relatives.set(PARENT,parent);
      }          
    }

    private TSTNode<T> node; // When you use it,pass T as U

    public TernarySearchTree() {
      node = new TSTNode<T>(',',null);  // When you use it,pass T as U 
    }
  }

版本2：从封闭类继承T

public class TernarySearchTree<T> {

    protected class TSTNode {
      // index values for accessing relatives array:
      protected static final int PARENT = 0,HIKID = 3;

      protected char splitchar;
      protected List<TSTNode> relatives;
      private T data;

      protected TSTNode(char splitchar,TSTNode parent) {
        this.splitchar = splitchar;
        relatives = new ArrayList<TSTNode>();
        for (int i = 0; i < HIKID; ++i) {  // Allocate 4 slots in relatives
          relatives.add(null);
        }
        relatives.set(PARENT,parent);
      }
    }

    private TSTNode node; 

    public TernarySearchTree() {
      node = new TSTNode(',null);  
    }
  }

版本3：使用地图(而不是列表)

public class TernarySearchTree<T> {

    protected class TSTNode {
      // index values for accessing relatives array:
      protected static final int PARENT = 0,HIKID = 3;

      protected char splitchar;
      protected Map<Integer,TSTNode> relatives;
      private T data;

      protected TSTNode(char splitchar,TSTNode parent) {
        this.splitchar = splitchar;
        // Create a hash map. No need to pre-allocate!
        relatives = new HashMap<Integer,TSTNode>(); 
        relatives.put(PARENT,parent); // set -> put
      }
    }

    private TSTNode node; 

    public TernarySearchTree() {
      node = new TSTNode(',null);  
    }
  }
}

版本4：将索引定义为枚举使用EnunMap(而不是哈希映射)

public class TernarySearchTree<T> {

    protected static enum Index {
      PARENT,LOKID,EQKID,HIKID;
    }

    protected class TSTNode {    
      protected char splitchar;
      protected EnumMap<Index,TSTNode parent) {
        this.splitchar = splitchar;
        // Create an EnumMap. 
        relatives = new EnumMap<Index,TSTNode>(Index.class);
        relatives.put(Index.PARENT,parent); 
      }
    }

    private TSTNode node; 

    public TernarySearchTree() {
      node = new TSTNode(',null);  
    }
  }

[更新2]
有一件事要记住：Use EnumMap instead of ordinal indexing