cdmlib-persistence/src/main/java/eu/etaxonomy/cdm/persistence/hibernate/CdmPostCrudObservableListener.java

   1 // $Id$
   2 /**
   3 * Copyright (C) 2007 EDIT
   4 * European Distributed Institute of Taxonomy
   5 * http://www.e-taxonomy.eu
   6 *
   7 * The contents of this file are subject to the Mozilla Public License Version 1.1
   8 * See LICENSE.TXT at the top of this package for the full license terms.
   9 */
  10
  11 package eu.etaxonomy.cdm.persistence.hibernate;
  12
  13 import java.util.HashSet;
  14 import java.util.Set;
  15
  16 import org.apache.log4j.Logger;
  17 import org.hibernate.event.PostDeleteEvent;
  18 import org.hibernate.event.PostDeleteEventListener;
  19 import org.hibernate.event.PostInsertEvent;
  20 import org.hibernate.event.PostInsertEventListener;
  21 import org.hibernate.event.PostLoadEvent;
  22 import org.hibernate.event.PostLoadEventListener;
  23 import org.hibernate.event.PostUpdateEvent;
  24 import org.hibernate.event.PostUpdateEventListener;
  25
  26 import eu.etaxonomy.cdm.model.common.CdmBase;
  27
  28 /**
  29  * ICdmPostCrudObserver implementors may register for this listener and their updatedAfterEvent will
  30  * be called after any CRUD (Create, Retrieve, Update, Delete).
  31  *
  32  * Only events whose entities are of type CdmBase will be propagated
  33  *
  34  * @author n.hoffmann
  35  * @created 24.03.2009
  36  * @version 1.0
  37  */
  38 public class CdmPostCrudObservableListener implements PostDeleteEventListener, PostInsertEventListener, PostLoadEventListener, PostUpdateEventListener{
  39
  40         private static final long serialVersionUID = -8764348096490526927L;
  41
  42         private static final Logger logger = Logger
  43                         .getLogger(CdmPostCrudObservableListener.class);
  44
  45         /**
  46          * Observing objects
  47          */
  48         private Set<ICdmPostCrudObserver> observers = new HashSet<ICdmPostCrudObserver>();
  49
  50         /**
  51          * Singleton instance
  52          */
  53         private static CdmPostCrudObservableListener instance;
  54
  55         /**
  56          * @return the singleton ConversationMediator
  57          */
  58         public static CdmPostCrudObservableListener getDefault(){
  59                 if(instance == null){
  60                         instance = new CdmPostCrudObservableListener();
  61                 }
  62                 return instance;
  63         }
  64
  65         /**
  66          * Register for updates
  67          *
  68          * @param observer
  69          */
  70         public static void register(ICdmPostCrudObserver observer){
  71                 getDefault().observers.add(observer);
  72         }
  73
  74         /**
  75          * Propagates the event to all registered objects.
  76          *
  77          * @param event
  78          */
  79         private void mediate(CdmCrudEvent event){
  80                 for( ICdmPostCrudObserver observer : observers){
  81                         // update the ICdmPostCrudObserver implementor
  82                         observer.update(event);
  83                 }
  84         }
  85
  86         /* (non-Javadoc)
  87          * @see org.hibernate.event.PostInsertEventListener#onPostInsert(org.hibernate.event.PostInsertEvent)
  88          */
  89         public void onPostInsert(PostInsertEvent event) {
  90                 logger.trace("post insert fired");
  91                 if(event.getEntity() instanceof CdmBase){
  92                         getDefault().mediate(CdmCrudEvent.NewInstance(event));
  93                 }
  94         }
  95
  96         /* (non-Javadoc)
  97          * @see org.hibernate.event.PostLoadEventListener#onPostLoad(org.hibernate.event.PostLoadEvent)
  98          */
  99         public void onPostLoad(PostLoadEvent event) {
 100                 logger.trace("post load fired");
 101                 if(event.getEntity() instanceof CdmBase){
 102                         getDefault().mediate(CdmCrudEvent.NewInstance(event));
 103                 }
 104         }
 105
 106         /* (non-Javadoc)
 107          * @see org.hibernate.event.PostUpdateEventListener#onPostUpdate(org.hibernate.event.PostUpdateEvent)
 108          */
 109         public void onPostUpdate(PostUpdateEvent event) {
 110                 logger.trace("post update fired");
 111                 if(event.getEntity() instanceof CdmBase){
 112                         getDefault().mediate(CdmCrudEvent.NewInstance(event));
 113                 }
 114         }
 115
 116         /* (non-Javadoc)
 117          * @see org.hibernate.event.PostDeleteEventListener#onPostDelete(org.hibernate.event.PostDeleteEvent)
 118          */
 119         public void onPostDelete(PostDeleteEvent event) {
 120                 logger.trace("post delete fired");
 121                 if(event.getEntity() instanceof CdmBase){
 122                         getDefault().mediate(CdmCrudEvent.NewInstance(event));
 123                 }
 124         }
 125
 126 }