# HandlingEventFactory.java

    /*
     * Copyright 2011 Marc Grue.
     *
     * Licensed  under the  Apache License,  Version 2.0  (the "License");
     * you may not use  this file  except in  compliance with the License.
     * You may obtain a copy of the License at
     *
     *   http://www.apache.org/licenses/LICENSE-2.0
     *
     * Unless required by applicable law or agreed to in writing, software
     * distributed  under the  License is distributed on an "AS IS" BASIS,
     * WITHOUT  WARRANTIES OR CONDITIONS  OF ANY KIND, either  express  or
     * implied.
     *
     * See the License for the specific language governing permissions and
     * limitations under the License.
     */
    package org.qi4j.sample.dcicargo.sample_b.data.factory;

    import java.util.Date;
    import org.qi4j.api.common.Optional;
    import org.qi4j.api.entity.EntityBuilder;
    import org.qi4j.api.injection.scope.Structure;
    import org.qi4j.api.mixin.Mixins;
    import org.qi4j.api.unitofwork.UnitOfWork;
    import org.qi4j.api.unitofwork.UnitOfWorkFactory;
    import org.qi4j.sample.dcicargo.sample_b.data.factory.exception.CannotCreateHandlingEventException;
    import org.qi4j.sample.dcicargo.sample_b.data.structure.handling.HandlingEvent;
    import org.qi4j.sample.dcicargo.sample_b.data.structure.handling.HandlingEventType;
    import org.qi4j.sample.dcicargo.sample_b.data.structure.location.Location;
    import org.qi4j.sample.dcicargo.sample_b.data.structure.tracking.TrackingId;
    import org.qi4j.sample.dcicargo.sample_b.data.structure.voyage.Voyage;

    /**
     * HandlingEventFactory
     *
     * Creates a valid handling event
     *
     * - Verifies if a voyage is mandatory or prohibited for the handling event type
     * - Verifies if a load/unload location is expected by the voyage
     *
     * Validations of TrackingId, Location and Voyage are considered out of this scope.
     */
    @Mixins( HandlingEventFactory.Mixin.class )
    public interface HandlingEventFactory
    {
        HandlingEvent createHandlingEvent( Date registrationTime,
                                           Date completionTime,
                                           TrackingId trackingId,
                                           HandlingEventType handlingEventType,
                                           Location location,
                                           @Optional Voyage voyage
        )
            throws CannotCreateHandlingEventException;

        public abstract class Mixin
            implements HandlingEventFactory
        {
            @Structure
            UnitOfWorkFactory uowf;

            public HandlingEvent createHandlingEvent( Date registrationTime,
                                                      Date completionTime,
                                                      TrackingId trackingId,
                                                      HandlingEventType handlingEventType,
                                                      Location location,
                                                      Voyage voyage
            )
                throws CannotCreateHandlingEventException
            {
                if( voyage == null && handlingEventType.requiresVoyage() )
                {
                    throw new CannotCreateHandlingEventException( "Voyage is required for handling event type " + handlingEventType );
                }

                else if( voyage != null && handlingEventType.prohibitsVoyage() )
                {
                    throw new CannotCreateHandlingEventException( "Voyage is not allowed with handling event type " + handlingEventType );
                }

                UnitOfWork uow = uowf.currentUnitOfWork();
                EntityBuilder<HandlingEvent> handlingEventBuilder = uow.newEntityBuilder( HandlingEvent.class );
                handlingEventBuilder.instance().registrationTime().set( registrationTime );
                handlingEventBuilder.instance().completionTime().set( completionTime );
                handlingEventBuilder.instance().trackingId().set( trackingId );
                handlingEventBuilder.instance().handlingEventType().set( handlingEventType );
                handlingEventBuilder.instance().location().set( location );
                handlingEventBuilder.instance().voyage().set( voyage );

                // Save and return
                return handlingEventBuilder.newInstance();
            }
        }
    }