@SuppressWarnings("unchecked")		// needed because of casting used in the equals method

public class KeyValuePair<K,V>			// demonstrate a Generic class with different types of instance data
{
	private K key;						// key stores the attribute name, e.g., "age"
	private V value;					// value stores the attribute value, e.g., a person's age
	
	public KeyValuePair()				// no-arg, kind of worthless
	{
		key=null;
		value=null;
	}
	
	public KeyValuePair(K key)			// we know the key but not the value (ye)
	{
		this.key=key;
		value=null;
	}
	
	public KeyValuePair(K key, V value)	// we know both the key and value
	{
		this.key=key;
		this.value=value;
	}
	
	public K getKey()					// accessors and mutators
	{
		return key;
	}
	
	public V getValue()
	{
		return value;
	}
	
	public void setKey(K key)
	{
		this.key=key;
	}
	
	public void setValue(V value)
	{
		this.value=value;
	}

	// implement the equal method to see if two KeyValuePairs are equal, we discuss this generic method later
	public static <K extends Comparable,V extends Comparable> boolean equal(KeyValuePair<? extends Comparable,? extends Comparable> p1, KeyValuePair<? extends Comparable, ? extends Comparable> p2)
	{
		K key1=(K)p1.getKey();					// note the casting, get the two KeyValuePair's keys
		K key2=(K)p2.getKey();			
		V value1=(V)p1.getValue();				// get the values
		V value2=(V)p2.getValue();				// if both keys are equal and both values are equal then they are equal
		if(key1.compareTo(key2)==0&&value1.compareTo(value2)==0) return true; else return false;
	}
}