//
// Returns false if array is full...
//

public class ArrayMemoDatabase implements MemoDatabase
{
  private MemoAssociation[] pair;
  private int counter;
  
  public ArrayMemoDatabase()
  {
    pair = new MemoAssociation[10];
    counter = 0;
  }
   
  public boolean insert( MemoAssociation m )
  {
    if ( counter == pair.length )
      return false;
    
    if ( containsKey(m.key()) )
      return false;
    
    pair[counter] = m;
    counter++;
    return true;
  }
   
  public String find( String key )
  {
    int location = slotFor( key );
    if ( location == -1 )
      return null;
    
    return pair[location].value();
  }
   
  public boolean remove( String key )
  {
    int location = slotFor( key );
    if ( location == -1 )
      return false;
    
    pair[location] = pair[counter-1];
    counter--;
    return true;
  }
   
  public boolean containsKey( String key )
  {
    return slotFor( key ) >= 0;
  }
   
  private int slotFor( String key )
  {
    for (int i = 0; i < counter; i++)
      if (key.equals( pair[i].key() ))
         return i;
    return -1;
  }
}