// package net.datastructures;
import java.util.Iterator;

/**
 * An interface for a dictionary storing (key-value) pairs.
 * @author Michael Goodrich
 */
//begin#fragment Dictionary
public interface Dictionary<K,V> {
//end#fragment Dictionary
  /** Returns the number of entries in the dictionary. */
//begin#fragment Dictionary
  public int size();
//end#fragment Dictionary
  /** Returns whether the dictionary is empty. */
//begin#fragment Dictionary
  public boolean isEmpty();
//end#fragment Dictionary
  /** Returns an entry containing the given key, or <tt>null</tt> if
   * no such entry exists. */
//begin#fragment Dictionary
  public Entry<K,V> find(K key) 	
    throws InvalidKeyException;
//end#fragment Dictionary
  /** Returns an iterator containing all the entries containing the
   * given key, or an empty iterator if no such entries exist. */
//begin#fragment Dictionary
  public Iterable<Entry<K,V>> findAll(K key) 
    throws InvalidKeyException;
//end#fragment Dictionary
  /** Inserts an item into the dictionary.  Returns the newly created
   * entry. */
//begin#fragment Dictionary
  public Entry<K,V> insert(K key, V value)  
    throws InvalidKeyException;
//end#fragment Dictionary
  /** Removes and returns the given entry from the dictionary. */
//begin#fragment Dictionary
  public Entry<K,V> remove(Entry<K,V> e) 		
    throws InvalidEntryException;
//end#fragment Dictionary
  /** Returns an iterator containing all the entries in the dictionary. */
//begin#fragment Dictionary
  public Iterable<Entry<K,V>> entries(); 
}
//end#fragment Dictionary