package de.fhdw.wtf.context.model.collections;
   
   import de.fhdw.wtf.context.model.Anything;
   import de.fhdw.wtf.persistence.meta.UserObject;
   
   /**
    * This class represents Maps. It contains 3 valued associations with one value K as key and another value V as value.
    * Values can be accessed via the key.
    * 
   * @param <K>
   *            Type of key elements.
   * @param <V>
   *            Type of value elements.
   */
  public class PersistentMap<K extends Anything, V extends Anything> extends MutableMap<K, V> {
  	
  	/**
  	 * Manages the links of this persistent map.
  	 */
  	private transient PersistentMapWithKeyValueLinks<Anything, Anything> links;
  	/**
  	 * Name of the underlying database association representing the 0..* relation.
  	 */
  	public static final String linksAssociationName = "links";
  	
  	/**
  	 * Creates an empty PersistentMap.
  	 */
  	public PersistentMap() {
  		this.initLinks();
  	}
  	
  	/**
  	 * Loads object from database.
  	 * 
  	 * @param userObject
  	 *            The underlying user object.
  	 */
  	public PersistentMap(final UserObject userObject) {
  		super(userObject);
  		this.initLinks();
  	}
  	
  	/**
  	 * Initializes the links. As this field is transient, this has to be done by both constructors.
  	 */
  	private void initLinks() {
  		final String assocName = PersistentMap.class.getName() + "." + linksAssociationName;
  		this.links = new PersistentMapWithKeyValueLinks<>(this.getObject(), assocName);
  	}
  	
  	@Override
  	public void put(final K key, final V value) {
  		this.links.put(key, value);
  	}
  	
  	@SuppressWarnings("unchecked")
  	@Override
  	public V get(final K key) {
  		return (V) this.links.get(key);
  	}
  	
  	@SuppressWarnings("unchecked")
  	@Override
  	public V remove(final K key) {
  		return (V) this.links.remove(key);
  	}
  }