/**

  * Copyright 2010 The Kuali Foundation Licensed under the

  * Educational Community 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.osedu.org/licenses/ECL-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.kuali.student.common.ui.server.applicationstate.dao.impl;

 import java.util.ArrayList;

 import java.util.Collection;

 import java.util.List;

 import javax.persistence.EntityManager;

 import javax.persistence.PersistenceContext;

 import javax.persistence.Query;

 import org.kuali.student.common.dao.impl.AbstractSearchableCrudDaoImpl;

 import org.kuali.student.common.exceptions.AlreadyExistsException;

 import org.kuali.student.common.exceptions.DoesNotExistException;

 import org.kuali.student.common.ui.server.applicationstate.dao.ApplicationStateDao;

 import org.kuali.student.common.ui.server.applicationstate.entity.ApplicationState;

 /**

  * This data access class stores the GUI (page, section, widget, etc.) 

  * application states as key value pairs in a database.

  */

 public class ApplicationStateDaoImpl extends AbstractSearchableCrudDaoImpl implements ApplicationStateDao {

         private final static String DEFAULT_USER_ID = "APPLICATION";

         @PersistenceContext(unitName = "ApplicationState")

         @Override

         public void setEm(EntityManager em) {

                 super.setEm(em);

         }

         /**

          * Gets an application states by <code>applicationId</code>, 

          * <code>referenceKey</code>, <code>referenceType</code> and 

          * <code>userId</code>.

          * 

          * @param applicationId Application id

          * @param referenceKey Reference key

          * @param referenceType Reference type

          * @param userId User id

          * @return An application state

          * @throws DoesNotExistException Thrown if application state does not exist

          */

         public ApplicationState getApplicationState(String applicationId, String referenceKey, String referenceType, String userId) throws DoesNotExistException {

                 Query query = em.createNamedQuery("ApplicationState.getApplicationStateByAppRefUserId");

                 query.setParameter("applicationId", applicationId);

                 query.setParameter("referenceKey", referenceKey);

                 query.setParameter("referenceType", referenceType);

                 query.setParameter("userId", userId);

                 try {

                         ApplicationState appState = (ApplicationState) query.getSingleResult();

                         return appState;

                 } catch(javax.persistence.NoResultException e) {

                         throw new DoesNotExistException("Application state does not exist");

                 }

         }

         /**

          * Gets an application states by <code>applicationId</code>, 

          * <code>referenceKey</code> and <code>referenceType</code>.

          * 

          * @param applicationId Application id

          * @param referenceKey Reference key

          * @param referenceType Reference type

          * @return A list of application states

          * @throws DoesNotExistException Thrown if application state does not exist

          */

         public ApplicationState getApplicationState(String applicationId, String referenceKey, String referenceType) throws DoesNotExistException {

                 return getApplicationState(applicationId, referenceKey, referenceType, DEFAULT_USER_ID);

         }

         /**

          * Creates and returns an application state.

          * 

          * @param appState Application state

          * @return A new application state

          * @throws AlreadyExistsException Thrown if application state already exists

          */

         public ApplicationState createApplicationState(ApplicationState appState) throws AlreadyExistsException {

                 if(appState.getUserId() == null) {

                         appState.setUserId(DEFAULT_USER_ID);

                 }

                 try {

                         getApplicationState(appState.getApplicationId(), appState.getReferenceKey(), appState.getReferenceType(), appState.getUserId());

                 } catch(DoesNotExistException e) {

                         return super.create(appState);

                 }

                 throw new AlreadyExistsException("Application state already exists");

         }

         /**

          * Creates a collection of application states and returns their ids.

          * 

          * @param appStateList collection of application states

          * @return A list of newly created application state ids

          * @throws AlreadyExistsException Thrown if application state already exists

          */

         public List<String> createApplicationState(Collection<ApplicationState> appStates) throws AlreadyExistsException {

                 List<String> newAppStateList = new ArrayList<String>();

                 for(ApplicationState appState : appStates) {

                         ApplicationState newAppState = createApplicationState(appState);

                         newAppStateList.add(newAppState.getId());

                 }

                 return newAppStateList;

         }

 }