cdmlib-model/src/main/java/eu/etaxonomy/cdm/aspectj/PropertyChangeAspect.aj

   1 package eu.etaxonomy.cdm.aspectj;
   2
   3 import java.lang.reflect.Field;
   4 import java.lang.reflect.InvocationTargetException;
   5
   6 import org.apache.log4j.Level;
   7 import org.apache.log4j.Logger;
   8 import org.aspectj.lang.Signature;
   9 import eu.etaxonomy.cdm.model.common.CdmBase;
  10
  11 /**
  12  * @author markus
  13  * Aspect class that adds a firePropertyChange call to all setter methods
  14  * which names start with "set" and that belong to subclasses form CdmBase
  15  * CdmBase defines the rest of the ProeprtyChangeSupport like listener registration
  16  */
  17 public aspect PropertyChangeAspect {
  18         static Logger logger = Logger.getLogger(PropertyChangeAspect.class);
  19
  20         pointcut execSetter(CdmBase cb): target(cb) && execution(void CdmBase+.set*(..) );
  21 //      /** *********** OLD ***********************/
  22 //      pointcut callSetter( CdmBase b ) : call( * CdmBase+.set*(..) ) && target( b );
  23
  24         /**
  25          * @param cb
  26          * Around aspect that will be weaven into the original setter methods of the CdmBase derived classes
  27          */
  28         void around( CdmBase cb ) : execSetter( cb )  {
  29                 //logger.setLevel(Level.DEBUG);
  30                 // get property that is set by setter method
  31                 Field property = getFieldOfSetter( thisJoinPointStaticPart.getSignature() );
  32                 if (property==null){
  33                         proceed( cb );
  34                 }else{
  35                         property.setAccessible(true);
  36                         String propertyName = property.getName();
  37                         //logger.debug("execSetter: The property is ["+propertyName+"]");
  38                         try {
  39                                 // use property attribute directly, not through get method.
  40                                 // get method might modify things, like setting a UUID when called for the first time.
  41                                 // Also get methods for booleans start with "is" or "has"
  42                                 Object oldValue = property.get(cb);
  43                                 proceed( cb );
  44                                 Object newValue = property.get(cb);
  45 //                              logger.error ("Prop: " + propertyName);
  46 //                              logger.warn("OLD:" + oldValue);
  47 //                              logger.warn("New:" + newValue);
  48                                 if (! isPersistentSet(newValue) && ! isPersistentSet(oldValue)  ){
  49                                         cb.firePropertyChange( propertyName, oldValue, newValue);
  50                                 }
  51                         } catch (NoSuchMethodException e) {
  52                                 e.printStackTrace();
  53                                 proceed( cb );
  54                         }catch (IllegalArgumentException e) {
  55                                 e.printStackTrace();
  56                                 proceed( cb );
  57                         }catch (IllegalAccessException e) {
  58                                 e.printStackTrace();
  59                                 proceed( cb );
  60                         } catch (InvocationTargetException e) {
  61                                 e.printStackTrace();
  62                                 proceed( cb );
  63                         }
  64                 }
  65         }
  66
  67         private boolean isPersistentSet(Object value){
  68                 if (value == null){
  69                         //logger.debug("(null) is not PS");
  70                         return false;
  71                 }else if (value.getClass().getSimpleName().equals("PersistentSet")){
  72                         logger.debug("Don't throw event for setter of Persistent Set");
  73                         return true;
  74                 }else{
  75                         //logger.warn(value.getClass().getSimpleName() + " is is not PS");
  76                         return false;
  77                 }
  78         }
  79
  80
  81                 /**
  82                  * @param signature
  83                  * Return the Field object that belongs to the signature of a setter method
  84                  * If no matching attribute can be found return null instead of throwing an NoSuchFieldException
  85                  * Removes first 3 characters of method name to find property name
  86                  */
  87                 private Field getFieldOfSetter( Signature signature ){
  88                         Field field = null;
  89                         String propertyName = "";
  90                         //logger.debug( "Getting the field name of setter ["+signature.getName() + "]" );
  91                         try{
  92                                 String methodName = signature.getName();
  93                                 propertyName = Character.toLowerCase(methodName.charAt(3)) + methodName.substring(4);
  94                                 field = signature.getDeclaringType().getDeclaredField( propertyName );
  95                         }catch( NoSuchFieldException e ){
  96                                 try{
  97                                         propertyName = "is"+propertyName.substring(0, 1).toUpperCase()+ propertyName.substring(1);
  98                                         field = signature.getDeclaringType().getDeclaredField( propertyName );
  99                                 }catch( NoSuchFieldException nsfe ){
 100                                         // cant find any matching attribute. catch error and return null
 101                                         return null;
 102                                 }
 103                         }
 104                         return field;
 105                 }
 106                 /**
 107                  * Fires a propertyChange Event
 108                  * @param cb  CdmBase that fires that Event
 109                  * @param property the property's name
 110                  * @param oldval the old value
 111                  * @param newval the new value
 112                   */
 113                 void fireLoggingPropertyChange( CdmBase cb,
 114                                 String property,
 115                                 Object oldval,
 116                                 Object newval) {
 117
 118                         //logger.debug( "PropertyChangeEvent: property [" + property + "], old value [" + oldval + "], new value [" + newval + "]");
 119                         // call firePropertyChange in original class. Method defined in CdmBase superclass!
 120                         cb.firePropertyChange( property,
 121                                         ( oldval == null ) ? oldval : oldval.toString(),
 122                                         ( newval == null ) ? newval : newval.toString());
 123                 }
 124
 125 }