/**
* An interface that <code>Entity</code>s may adopt if the process of deleting them is controlled in the
* following way:
* <ol>
* <li>At some point in its lifecycle it may be deleted permanently.  This condition depends on the state
* of the entity and the other objects that the entity can navigate to.
* <li>At some point in its lifecycle it may only be deleted temporarily by setting a flag in the data
* source that marks it as deleted.  Again, this condition depends on the state of the entity and the other
* objects that the entity can navigate to.
* <li>(optionally) At some point in its lifecycle the entity cannot be deleted in any way.
* </ol>
*
* @author Jesse Costello-Good
* @version $Id: TieredDeleteEntity.java,v 1.5 2003/08/06 15:51:16 jesse Exp $
*/
public interface TieredDeleteEntity extends Entity {

   /**
    * Transformer that will filter out all the not hide deleted entities from a collection of
    * <code>TieredDeleteEntity</code>s.
    */
   public static final ListFilter IS_DELETED_FILTER = new ListFilter() {
      public boolean in( Object o ) {
         return ((TieredDeleteEntity) o).isHideDeleted();
      }
   };

   /**
    * Transformer that will filter out all the hide deleted entities from a collection of
    * <code>TieredDeleteEntity</code>s.
    */
   public static final ListFilter NOT_DELETED_FILTER = new InverseListFilter(IS_DELETED_FILTER);

   /**
    * Whether the entity may be deleted permanently by erasing it from the data source at this time.
    */
   public boolean mayEraseDelete();

   /**
    * Whether the entity may be deleted temporarily by hiding it at this time.
    */
   public boolean mayHideDelete();

   /**
    * Whether the entity is currently deleted temporarily (and may be undeleted).
    */
   public boolean isHideDeleted();

   /**
    * Set whether the entity is deleted temporarily.
    */
   public void setHideDeleted(boolean hideDeleted);

   /**
    * Bean interface for whether this entity is in some way deletable.
    */
   public boolean isDeletable();
}