java自定义堆栈

package com.zhb.corejava.util; public class Stack<E> { private E[] elementData; private int top; private int count; @SuppressWarnings("unchecked") public Stack(int size) { this.elementData = (E[]) new Object[size]; top = -1; count = 0; } public Stack() { this(10); } /** * 返回堆栈长度 * @return */ public int getSize(){ return elementData.length; } /** * 返回栈中元素的个数 * @return */ public int getElementCount() { return count; } /** * 判栈空 * @return */ public boolean isEmpty(){ return top == -1; } /** * 判栈满 * @return */ public boolean isFull(){ return top == (elementData.length-1); } /** * 入栈操作 * @param object */ public void push(E object){ if(isFull()){ throw new RuntimeException("栈已经满"); }else{ elementData[++top] = object; count++; } } /** * 出栈操作，并返回被出栈的元素 * @return */ public E pop(){ if(isEmpty()){ throw new RuntimeException("栈是空的"); }else{ count--; return elementData[top--]; } } /** * 返回栈顶元素 * @return */ public E peek(){ if(isEmpty()){ throw new RuntimeException("栈是空的"); }else{ return elementData[top]; } } }

编写测试类：

package com.zhb.corejava.util; public class ClientTest { public static void main(String[] args) { Stack<User> stack = new Stack<User>(); User user1 = new User("张三", 1); User user2 = new User("李四", 2); User user3 = new User("王五", 2); stack.push(user1); stack.push(user2); stack.push(user3); System.out.println("stack.size====" + stack.getSize()); User user = stack.pop(); System.out.println("user.name==1==" + user.getName()); System.out.println("-------------------------------------------"); user = stack.pop(); System.out.println("user.name==2==" + user.getName()); System.out.println("-------------------------------------------"); user = stack.pop(); System.out.println("user.name==3==" + user.getName()); System.out.println("stack.size====" + stack.getSize()); System.out.println("-------------------------------------------"); stack.push(user1); System.out.println("stack.size====" + stack.getSize()); System.out.println("stack.isEmpty==="+stack.isEmpty()); System.out.println("stack.isFull==="+stack.isFull()); } }