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package org.onetwo.common.utils.map;

import java.util.Collections;
import java.util.Map;
import java.util.Map.Entry;

public class KVEntry implements Map.Entry {
	
	public static class ConstantKVEntry extends KVEntry {

		public ConstantKVEntry(K key, V val) {
			super(key, val);
		}

		@Override
		public void setKey(K key) {
			throw new UnsupportedOperationException("read only!");
		}

		@Override
		public V setValue(V value) {
			throw new UnsupportedOperationException("read only!");
		}
		
	}
	
	public static  KVEntry create(Entry entry){
		return create(entry.getKey(), entry.getValue(), null);
	}
	
	public static  KVEntry create(K k, V v){
		return create(k, v, null);
	}
	
	public static  KVEntry create(K k, V v, Map map){
		KVEntry entry = new KVEntry(k, v);
		if(map!=null)
			map.put(k, v);
		return entry;
	}
	
	public static  KVEntry constEntry(K k, V v, Map map){
		KVEntry entry = new ConstantKVEntry(k, v);
		if(map!=null)
			map.put(k, v);
		return entry;
	}
	
	public static  Map freezeMap(Map map){
		return Collections.unmodifiableMap(map);
	}
	
	
	private K key;
	private V value;
	
	public KVEntry(K key, V val) {
		super();
		this.key = key;
		this.value = val;
	}

	public K getKey() {
		return key;
	}

	public void setKey(K key) {
		this.key = key;
	}

	public V getValue() {
		return value;
	}

	public V setValue(V value) {
		V t = this.value;
		this.value = value;
		return t;
	}
}