18.Java基於LinkedList實現Map

package com.cl.map;

import com.cl.set.FileOperation;
import com.cl.set.LinkedList;

import java.util.ArrayList;

public class LinkedListMap<K,V> implements Map<K,V> {

    private class Node{
        public K key;
        public  V value;
        public Node next;

        public Node(K key, V value,Node next) {
            this.key = key;
            this.value = value;
            this.next = next;
        }

        public Node(K key) {
            this(key,null,null);
        }

        public Node() {
            this(null,null,null);
        }

        @Override
        public String toString() {
            return key.toString()+":"+value.toString();
        }
    }

    private Node dummyHead;
    private  int size;

    public LinkedListMap() {
        dummyHead = new Node();
        size=0;
    }

    private Node getNode(K key){
        Node cur = dummyHead.next;
        while(cur!=null){
            if(cur.key.equals(key)){
                return cur;
            }
            cur=cur.next;
        }
        return null;
    }

    @Override
    public void add(K key, V value) {
        Node node = getNode(key);
        if(node==null){
            dummyHead.next = new Node(key,value,dummyHead.next);
            size++;
        }else{
            //重複,改變value
            node.value= value;
        }
    }

    @Override
    public V remove(K key) {
        Node pre = dummyHead;
        while(pre.next!=null){
            if(pre.next.key.equals(key)){
                break;
            }
            pre = pre.next;
        }
        if(pre.next!=null){
            Node deNode = pre.next;
            pre.next=deNode.next;
            deNode.next=null;
            size--;
            return deNode.value;
        }
        return null;
    }

    @Override
    public boolean contains(K key) {
        return getNode(key)!=null;
    }

    @Override
    public V get(K key) {
        Node node = getNode(key);
        return node==null?null:node.value;
    }

    @Override
    public void set(K key, V value) {
        Node node = getNode(key);
        if(node==null){
            throw new IllegalArgumentException(key.toString()+"not exist");
        }
        node.value = value;
    }

    @Override
    public int getSise() {
        return size;
    }

    @Override
    public boolean isEmpty() {
        return size==0;
    }

  
}