java 实现链栈存储的方法

packagecom.learn.algorithm.linkStack;
/**
 * 链栈实现
 * @author Jiekun.Cui
 * @param 
 */
publicclassLinkStack {
 
  privateLinkStack.Node top =newNode();
  privateintsize=0;
   
  /**
   * 进栈
   * @param t
   * @return ;
   */
  publicbooleanpush(T t){
     
    if( isEmpty() ) {
      top.next =newNode(t);
       
    }else{
      Node newNode =newNode(t, top.next);
      top.next = newNode;
    }
    size ++ ;
    returntrue;
  }
   
  /**
   * 出栈
   * @param t
   * @return
   */
  publicT pop(){
     
    if( isEmpty() ) {
      returnnull;
    }else{
      LinkStack.Node node = top.next;
      top.next = node.next;
      size --;
      returnnode.getT();
    }
  }
   
   
  /**
   * 获取栈顶元素
   * @return
   */
  publicT getTop(){
    if( isEmpty() ) {
      returnnull;
    }else{
      returntop.next.getT();
    }
  }
   
   
  /**
   * 判断栈是不是为空
   * @return
   */
  publicbooleanisEmpty(){
    returnsize() ==0;
  }
   
  /**
   * 返回栈的大小
   * @return
   */
  publicintsize(){
    returnsize;
  }
   
   
   
   
  /**
   * @author 链栈的节点类
   * @param 
   */
  classNode{
    privateT t =null;
    privateNode next =null;
     
    publicNode(){
       
    }
    publicNode(T t){
      this.t = t;
    }
    publicNode(T t,Node next){
      this.t = t;
      this.next =next;
    }
     
     
    publicT getT() {
      returnt;
    }
    publicvoidsetT(T t) {
      this.t = t;
    }
     
    publicNode getNext() {
      returnnext;
    }
    publicvoidsetNext(Node next) {
      this.next = next;
    }
  }
}