/**
 * Copyright (C) 2011 Brian Ferris <bdferris@onebusaway.org>
 *
 * 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.onebusaway.federations.annotations;

import org.onebusaway.exceptions.ServiceException;
import org.onebusaway.federations.FederatedService;
import org.onebusaway.federations.FederatedServiceCollection;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.HashSet;
import java.util.Set;

/**
 * Provides a {@link FederatedServiceMethodInvocationHandler} implementation for
 * the {@link FederatedByEntityIdsMethod} annotation.
 * 
 * @author bdferris
 */
class FederatedByEntityIdsMethodInvocationHandlerImpl implements
    FederatedServiceMethodInvocationHandler {

  private int _argumentIndex;

  public FederatedByEntityIdsMethodInvocationHandlerImpl(int argumentIndex) {
    _argumentIndex = argumentIndex;
  }

  public int getArgumentIndex() {
    return _argumentIndex;
  }

  @SuppressWarnings("unchecked")
  public Object invoke(FederatedServiceCollection collection, Method method,
      Object[] args) throws ServiceException, IllegalArgumentException,
      IllegalAccessException, InvocationTargetException {

    Iterable<String> entityIds = (Iterable<String>) args[_argumentIndex];
    Set<String> agencyIds = new HashSet<String>();
    for (String entityId : entityIds)
      agencyIds.add(AgencyIdSupport.getAgencyIdFromEntityId(entityId));
    FederatedService service = collection.getServiceForAgencyIds(agencyIds);
    return method.invoke(service, args);
  }

}