Set改写成Map使用

 

package com.kael;

import java.io.Serializable;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;

/**
 * 
 *  
 * @Title:SetAndMap 
 * @Description: Map和Set 装换
 * @Copyright:Copyright (c) 2012 
 * @Date:2012-7-20 
 * @author feilong.li
 */
public class SetAndMap {
	
	public static void main(String[] args) {
		SetMap<String, Integer> scores = new SetMap<String, Integer>();
		Map<String, Integer> map = new HashMap<String, Integer>();
		scores.put("C", 90);
		scores.put("Java", 100);
		scores.put("Oracle", 98);
		
		map.put("C", 90);
		map.put("Java", 100);
		map.put("Oracle", 98);
		
		System.out.println(scores);
		System.out.println("scores.size() = " + scores.size());
		System.out.println(scores.containsKey("Java"));
		System.out.println(scores.containsValue(100));
		System.out.println(scores.getValue("C"));
		System.out.println(scores.removeEntry("C"));
		System.out.println(scores);
		scores.clear();
		System.out.println(scores);
		scores.putAll(map);
		System.out.println(scores);
	}
	
}

class SimpleEntry<K,V> implements Map.Entry<K, V> ,Serializable {
	
	/**
	 * 
	 */
	private static final long serialVersionUID = -5468059496835899481L;
	private K key;
	private V value;
	
	public SimpleEntry (K key,V value) {
		this.key = key;
		this.value = value;
	}
	public SimpleEntry(Map.Entry<? extends K, ? extends V> entry) {
		this.key = entry.getKey();
		this.value = entry.getValue();
	}
	
	@Override
	public K getKey() {
		return key;
	}

	@Override
	public V getValue() {
		return value;
	}

	@Override
	public V setValue(V value) {
		V oldValue = this.value;
		this.value = value;
		return oldValue;
	}
	
	@Override
	public int hashCode() {
		return key == null ? 0 : key.hashCode();
	}
	@Override
	public boolean equals(Object obj) {
		if(obj == this) {
			return true;
		}
		if(obj.getClass() == this.getClass()) {
			SimpleEntry<K, V> simpleEntry = this;
			return simpleEntry.getKey().equals(getKey());
		}
		return false;
	}
	@Override
	public String toString() {
		return key +"="+ value;
	}
	
}

/*
 * 定义自己的Map
 */
class SetMap<K, V> extends HashSet<SimpleEntry<K, V>> {
	
	private static final long serialVersionUID = -9050259671066619118L;

	/**
	 * 清空
	 */
	public void clear() {
		super.clear();
	}
	
	/**
	 * 判断是否包含某个key
	 */
	public boolean containsKey(K key) {
		return super.contains(new SimpleEntry<K, V>(key,null));
	}
	
	/**
	 * 判断是否包含某一个value
	 */
	public boolean containsValue(V v) {
		for(SimpleEntry<K, V> entry : this) {
			if(entry.getValue().equals(v)) {
				return true;
			}
		}
		return false;
	}
	
	/**
	 * 指定key返回value
	 */
	public V getValue(K key) {
		for(SimpleEntry<K, V> entry : this) {
			if(entry.getKey().equals(key)) {
				return entry.getValue();
			}
		}
		return null;
	}
	
	/**
	 * 将指定key-value放入Map
	 */
	public V put(K key,V value) {
		add(new SimpleEntry<K, V>(key,value));
		return value;
	}
	
	/**
	 * 将另一个map的全部key-value对放入这个Map中
	 */
	public void putAll(Map<? extends K, ? extends V> map) {
		for(K key : map.keySet()) {
			add(new SimpleEntry<K, V>(key, map.get(key)));
		}
	}
	
	/**
	 * 根据key删除指定的key-value
	 */
	public V removeEntry(K key) {
		for(Iterator<SimpleEntry<K, V>> iterator = this.iterator();iterator.hasNext();) {
			SimpleEntry<K, V> entry = iterator.next();
			if(entry.getKey().equals(key)) {
				iterator.remove();
				return entry.getValue();
			}
		}
		return null;
	}
	
	/**
	 * 获取这个Map中包含多少对key-value
	 */
	public int size() {
		return super.size();
	}
}




输出结果：

[C=90, Oracle=98, Java=100]
scores.size() = 3
true
true
90
90
[Oracle=98, Java=100]
[]
[C=90, Oracle=98, Java=100]