/**
 *
 * Copyright
 * 2009-2015 Jayway Products AB
 * 2016-2017 Föreningen Sambruk
 *
 * Licensed under AGPL, Version 3.0 (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.gnu.org/licenses/agpl.txt
 *
 * 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 se.streamsource.streamflow.infrastructure.event.domain.source.helper;

import org.qi4j.api.specification.Specification;
import se.streamsource.streamflow.infrastructure.event.domain.DomainEvent;
import se.streamsource.streamflow.infrastructure.event.domain.source.EventVisitor;

import java.util.HashMap;
import java.util.Map;

/**
 * Event handling router. Add specification->visitor routes. When an event comes in
 * the router will ask each specification if it matches, and if so, delegate to the
 * visitor and return whether it successfully handled it or not. If no routes match,
 * returns true.
 */
public class EventRouter
   implements EventVisitor
{
   Map<Specification<DomainEvent>, EventVisitor> routes = new HashMap<Specification<DomainEvent>, EventVisitor>( );

   public EventRouter route( Specification<DomainEvent> specification, EventVisitor visitor)
   {
      routes.put( specification, visitor );

      return this;
   }

   /**
    * Route an event to a visitor whose specification matches it. If no
    * specification matches, then return true. Otherwise return the status
    * of the visitor that was matched.
    *
    * @param event the event
    * @return true if event was handled successfully.
    */
   public boolean visit( DomainEvent event )
   {
      for (Specification<DomainEvent> specification : routes.keySet())
      {
         if (specification.satisfiedBy( event ))
         {
            EventVisitor eventVisitor = routes.get( specification );
            return eventVisitor.visit( event );
         }
      }

      return true;
   }
}