# StateChangeNotificationConcern.java

    /*
     * Copyright (c) 2009, Rickard Öberg. All Rights Reserved.
     *
     * 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.spi.entitystore;

    import org.qi4j.api.concern.ConcernOf;
    import org.qi4j.api.injection.scope.Service;
    import org.qi4j.spi.entity.EntityState;
    import org.qi4j.spi.module.ModuleSpi;

    /**
     * State change notification Concern.
     */
    public abstract class StateChangeNotificationConcern
        extends ConcernOf<EntityStoreSPI>
        implements EntityStoreSPI
    {
        @Service
        Iterable<StateChangeListener> listeners;

        @Override
        public StateCommitter applyChanges( final EntityStoreUnitOfWork unitofwork,
                                            final Iterable<EntityState> state
        )
        {
            final StateCommitter committer = next.applyChanges( unitofwork, state );
            return new StateCommitter()
            {
                @Override
                public void commit()
                {
                    for( StateChangeListener listener : listeners )
                    {
                        listener.notifyChanges( state );
                    }
                    committer.commit();
                }

                @Override
                public void cancel()
                {
                    committer.cancel();
                }
            };
        }
    }