尝试编译时出现以下错误:
Btree.scala:9:错误:找不到参数排序的隐式值:Ordering[K] 抽象类 Node[K,V] 扩展 TreeMap[K,V]
TreeMap 应该接受我提供的隐式 Ordering[A] val。也许隐式参数需要在实例化 Btree(TreeMap) 的对象 Tester 中?我更愿意将隐式声明保留在 Btree 类中,因为我希望 Ordering 有一个实现 Comparable[K] 的类型 K。说得通?
package disttree {
import scala.collection.immutable.TreeMap
class Btree[K <: Comparable[K],V](fanout:Int) {
implicit object DefaultOrder extends Ordering[K] {
def compare(k1: K, k2: K) = k1 compareTo k2
}
abstract class Node[K,V] extends TreeMap[K,V]
class InnerNode[K,V] extends Node[K,V]
class LeafNode[K,V] extends Node[K,V]
val root = new InnerNode[K,V]()
def search(n: Node[K,V], key: K): Option[(K,V)] = {
return n.find(_ == key)
}
def insert(key: K, value: V) { }
def delete(key: K) { }
}
}
import disttree._;
object Tester {
def main(args: List[String]) = {
var t = new Btree[Int, Any](2)
t.insert(1, "goodbye")
Console.println(t)
}
}