18.Java基于LinkedList实现Map

柔光的暖阳◎ 2022-02-28 14:38 234阅读 0赞

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{
                //重复,改变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;
        }
    
      
    }