package org.trails.callback;

 import ognl.Ognl;

 import ognl.OgnlException;

 import org.trails.TrailsRuntimeException;

 import org.trails.descriptor.ObjectReferenceDescriptor;

 import org.trails.descriptor.OwningObjectReferenceDescriptor;

 import org.trails.persistence.PersistenceService;

 /**

  * This guy is responsible for returning from an add or remove on a association.

  */

 public class AssociationCallback extends EditCallback

 {

         private ObjectReferenceDescriptor od;

         private boolean oneToOne;

         /**

          * @param pageName

          * @param model

          */

         public AssociationCallback(String pageName, Object model, ObjectReferenceDescriptor od)

         {

                 super(pageName, model);

                 this.od = od;

                 this.setOneToOne(od.supportsExtension(OwningObjectReferenceDescriptor.class.getName()));

         }

         public void save(PersistenceService persistenceService, Object newObject)

         {

                 executeOgnlExpression(findAddExpression(), newObject);

                 persistenceService.save(getModel());

         }

         public void remove(PersistenceService persistenceService, Object object)

         {

                 try

                 {

                         Ognl.setValue(findAddExpression(), model, null);

                         Ognl.getValue(findAddExpression(), model);

                         persistenceService.save(getModel());

                         persistenceService.remove(object);

                 } catch (OgnlException e)

                 {

                         throw new TrailsRuntimeException(e, getModel().getClass());

                 }

         }

         /**

          * @param previousModel

          */

         private void executeOgnlExpression(String ognlExpression, Object newObject)

         {

                 try

                 {

                         Ognl.setValue(ognlExpression, model, newObject);

                         Ognl.getValue(ognlExpression, model);

                 } catch (OgnlException e)

                 {

                         throw new TrailsRuntimeException(e, model.getClass());

                 }

         }

         public boolean isOneToOne()

         {

                 return oneToOne;

         }

         public void setOneToOne(boolean oneToOne)

         {

                 this.oneToOne = oneToOne;

         }

         private String findAddExpression()

         {

                 return od.getName();

         }

 }