Open Source Projects Europe

package eu.alfred.event_manager.client;

import java.io.IOException;

import java.util.ArrayList;

import java.util.List;

import org.codehaus.jackson.map.ObjectMapper;

import eu.alfred.event_manager.model.AnalyticsParameters;

import eu.alfred.event_manager.model.Event;

import eu.alfred.recommendations.util.DataTransformationsHandler;

import eu.alfred.recommendations.util.WebServiceClient;

/**

 * This class serves as a client for the services provided by the Event Manager.

 * It provides methods for performing CRUD operation on events and adding/deleting participants from events.

 * 

 * @author tasos

 *

 */

public class EventManagerClient {

  private final String baseUrl = "http://80.241.219.213:1999/Alfred/";

  private DataTransformationsHandler dtHandler;

  private WebServiceClient wsClient;

  public EventManagerClient() {

      dtHandler = new DataTransformationsHandler();

      wsClient = new WebServiceClient();

  }

  /**

   * Retrieves an event entry from the EM, with the specified ID.

   * 

   * @param eventId A String with the unique identification of the event. 

   * @return The event with the specified ID, if successfully retrieved. 

   */

  public Event getEvent(String eventId) {     

      String requestUrl = baseUrl +"Event?EventID="+eventId;

      // There can be only one event with a specific id. We use "get(0)" because of the generic "doGetRequest"

      // utility method which returns a List<Object>

      Event event = (Event)wsClient.doGetRequest(requestUrl, Event.class).get(0);

      return event;       

  }

  /**

   * Creates a new entry of an event if the event doesn't exist, or updates the event if already present.

   * 

   * @param newEvent The Event object for the new event entry.

   * @return The new Event entry created if the operation was successful, or null otherwise.

   */

  public Event addEvent(Event newEvent) {

      String eventAsJson = dtHandler.mapObjectToJson(newEvent);   

      String result = wsClient.doPostRequestToCreate(baseUrl + "AddEvent", eventAsJson);

      ObjectMapper mapper = new ObjectMapper();

      try {

          return (Event) mapper.readValue(result,Event.class);

      } catch (IOException e) { 

          e.printStackTrace();

      }

      return null;

  }

  /**

   * Deletes an event entry with the specified ID.

   * 

   * @param eventId A String with the unique identification of the event to be deleted.

   * @return The Event that was deleted with the operation.

   */

  public Object deleteEvent(String eventId) { 

      String requestUrl = baseUrl +"DeleteEvent?EventID=" + eventId;

      Event deletedEvent = (Event) wsClient.doDeleteRequestEM(requestUrl, Event.class);

      // Why the hell Dimitri's service returns an event that was just now deleted?

      return deletedEvent;

  }

  /**

   * Retrieves a list of events from the Event Manager, based on parameters described in an AnalyticsParameters object.

   * The AnalyticsParameters object makes use of calculations of the OLAP cubes defined in the EM.

   * 

   * @param parameters The AnalyticsParameters object with the parameters for filtering the events to be retrieved.

   * @return A List of Event objects which satisfy the defined parameters.

   */

  public List<Event> getEvents(AnalyticsParameters parameters) { 

      String paramsAsJson = dtHandler.mapObjectToJson(parameters);

      List<Event> events = (List<Event>)(List<?>) wsClient.doPostRequestToRetrieve(baseUrl + 

                                                                  "QueryEvents", paramsAsJson, Event.class);

      return events;

  }

   /**

    * Adds a user with a specified Id as a participant in an event with a specified Id.

    * 

    * @param eventId The unique identification of the event in which the user will participate.

    * @param participantId The unique identification of the user who will participate in the event

    * @return A Boolean indicating the success or failure of the operation

    */

   public Boolean addParticipant(String eventId, String participantId) {

      Boolean operationResult= wsClient.doGetRequest(baseUrl + "AddParticipant?EventID="+eventId+"&UserID="+participantId);

      return operationResult;

  }

   /**

    * Deletes a user entry as a participant in an event. 

    * 

    * @param eventId he unique identification of the event from which the user will be removed as a participant.

    * @param participantId The unique identification of the user who will be removed as a participant in the event

    * @return A Boolean indicating the success or failure of the operation

    */

  public Boolean deleteParticipant(String eventId, String participantId) { 

      String operationResult= wsClient.doDeleteRequest(baseUrl + "AddParticipant?EventID="+eventId+"&UserID="+participantId);

      if(operationResult=="true")

          return true;

      return false;

  }

}