import java.util.Iterator;

public abstract class AbstractMap<K,V> implements Map206<K,V>
{
    protected class Entry<L,W> implements MEntry<L,W>
    {
    	private final L key;
    	private final W value;
	public L getKey()
	{
	    return key;
	}
	public W getValue()
	{
	    return value;
	}
	public Entry(L k, W v)
	{
	    this.key=k;
	    this.value=v;
	}
    }
    
    @Override
    public boolean isEmpty() { return size()==0; }
    
    
    private class KeyIterator<L> implements Iterator<K>
    {
	private Iterator<MEntry<K,V>> entries = entrySet().iterator();
	public boolean hasNext() { return entries.hasNext(); }	
	public K next() { return entries.next().getKey(); }
	public void remove(L key) { throw new UnsupportedOperationException(); }
    }
    private class KeyIterable<L> implements Iterable<K>
    {
	public Iterator<K> iterator()  {  return new KeyIterator<K>(); }
    }
    @Override
    public Iterable<K> keySet() { return new KeyIterable<K>(); }

    
    private class ValueIterator<L> implements Iterator<V>
    {
	private Iterator<MEntry<K,V>> entries = entrySet().iterator();
	public boolean hasNext() { return entries.hasNext(); }	
	public V next() { return entries.next().getValue(); }
	public void remove(L key) { throw new UnsupportedOperationException(); }
    }
    private class ValueIterable<L> implements Iterable<V>
    {
	public Iterator<V> iterator()  {  return new ValueIterator<V>(); }
    }
    @Override
    public Iterable<V> values() { return new ValueIterable<V>(); }

}