linkedstack5.java

来自「Thinking In Java 原文章」· Java 代码 · 共 38 行

// generics/LinkedStack5.java
// TIJ4 Chapter Generics, Exercise 5, page 626
/* Remove the type parameter on the Node class and modify the rest of the
* code in LinkedStack.java to show that an inner class has access to the
* generic type parameters of its outer class.
*/

public class LinkedStack5<T> {
	// make Node a nonstatic class to access nonstatic T:
	private class Node {
		T item;
		Node next;
		Node() { item = null; next = null; }
		Node(T item, Node next) {
			this.item = item;
			this.next = next;
		}
		boolean end() { return item == null && next == null; }
	}
	private Node top = new Node(); // End sentinel
	public void push(T item) {
		top = new Node(item, top);
	}
	public T pop() {
		T result = top.item;
		if(!top.end())
			top = top.next;
		return result;
	}
	public static void main(String[] args) {
		LinkedStack5<String> lss = new LinkedStack5<String>();
		for(String s: "Phasers on stun!".split(" ")) 
			lss.push(s);
		String s;
		while((s = lss.pop()) != null)
			System.out.println(s);
	}
}