/*
* Copyright (c) 2010 Lockheed Martin Corporation
*
* 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.eurekastreams.server.persistence.mappers.db;
import java.util.HashSet;
import java.util.Hashtable;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.eurekastreams.server.persistence.mappers.BaseArgDomainMapper;
import org.eurekastreams.server.persistence.mappers.requests.BulkActivityDeleteResponse;
/**
* Given a group id, this mapper deletes all Activities and related objects (Comments and StarredActivities) from the
* DB.
*/
public class DeleteGroupActivity extends BaseArgDomainMapper<Long, BulkActivityDeleteResponse>
{
/**
* Deletes all Activities (and related objects) that were posted to specified group.
*
* @param inRequest
* the group id.
* @return {@link BulkActivityDeleteResponse} with info. needed to clean up cache and search index.
*
*/
@Override
public BulkActivityDeleteResponse execute(final Long inRequest)
{
// get groupDTO to fetch group stream id
Long groupStreamId = getGroupStreamId(inRequest);
if (groupStreamId == null)
{
// short-circut as group is no longer present.
return new BulkActivityDeleteResponse();
}
// get activity ids to return (cache and search index cleanup)
List<Long> activityIds = getActivityIds(groupStreamId);
// get comment ids to return (cache and search index cleanup)
List<Long> commentIds = getCommentIds(groupStreamId);
// get people with starred Activities map (cache clean up).
Map<Long, Set<Long>> peopleWithStarredActivities = getPeopleWithStarredActivities(inRequest);
// Why the following queries use sub-selects:
// FROM HIBERNATE DOCS: No joins can be specified in a bulk HQL query. Sub-queries can be used in the
// where-clause,
// where the subqueries themselves may contain joins.
getEntityManager().createQuery(
"DELETE FROM Comment c WHERE c.target.id IN"
+ " (SELECT a.id FROM Activity a WHERE a.recipientStreamScope.id = :groupStreamId)")// \n
.setParameter("groupStreamId", groupStreamId).executeUpdate();
// delete activity from currentUser's starred activity collections in DB.
getEntityManager().createQuery(
"DELETE FROM StarredActivity where activityId IN"
+ " (SELECT a.id FROM Activity a WHERE a.recipientStreamScope.id = :groupStreamId)")// \n
.setParameter("groupStreamId", groupStreamId).executeUpdate();
// delete activity hashtags for this group stream
if (!activityIds.isEmpty())
{
getEntityManager().createQuery("DELETE FROM StreamHashTag where activityId IN (:activityIds)")
.setParameter("activityIds", activityIds).executeUpdate();
}
// delete the activities.
getEntityManager().createQuery("DELETE FROM Activity a WHERE a.recipientStreamScope.id = :groupStreamId")
.setParameter("groupStreamId", groupStreamId).executeUpdate();
// delete any Person's bookmark to the group that's just about to be deleted
getEntityManager().createQuery("DELETE FROM PersonBookmark pb where pb.pk.scopeId = :groupStreamId)")
.setParameter("groupStreamId", groupStreamId).executeUpdate();
return new BulkActivityDeleteResponse(activityIds, commentIds, peopleWithStarredActivities);
}
/**
* Get the stream id for a group.
*
* @param groupId
* Group id.
* @return The stream id for a group.
*/
@SuppressWarnings("unchecked")
private Long getGroupStreamId(final Long groupId)
{
List<Long> result = getEntityManager().createQuery(
"SELECT g.streamScope.id FROM DomainGroup g WHERE g.id = :groupId").setParameter("groupId", groupId)
.getResultList();
return result.size() == 0 ? null : result.get(0);
}
/**
* Return activity ids for a group. This only returns the number of results based on max list size in cache, no need
* to return more than that.
*
* @param groupStreamId
* group stream id.
* @return activity ids for a group.
*/
@SuppressWarnings("unchecked")
private List<Long> getActivityIds(final Long groupStreamId)
{
return getEntityManager().createQuery(
"SELECT a.id FROM Activity a WHERE a.recipientStreamScope.id = :groupStreamId ORDER BY a.id DESC")
.setParameter("groupStreamId", groupStreamId).getResultList();
}
/**
* Return comment ids for all activities in a group.
*
* @param groupStreamId
* group stream id.
* @return Comment ids for all activities in a group.
*/
@SuppressWarnings("unchecked")
private List<Long> getCommentIds(final Long groupStreamId)
{
return getEntityManager().createQuery(
"SELECT c.id FROM Comment c, Activity a"
+ " WHERE a.recipientStreamScope.id = :groupStreamId AND c.target.id = a.id") // \n
.setParameter("groupStreamId", groupStreamId).getResultList();
}
/**
* Return Map keyed by Person id that has set of activity ids that the person has starred that belong to the group
* being deleted.
*
* @param groupStreamId
* Group stream id.
* @return Map keyed by Person id that has set of activity ids that the person has starred that belong to the group
* being deleted.
*/
@SuppressWarnings("unchecked")
private Map<Long, Set<Long>> getPeopleWithStarredActivities(final Long groupStreamId)
{
Hashtable<Long, Set<Long>> results = new Hashtable<Long, Set<Long>>();
List<Object[]> queryResults = getHibernateSession().createQuery(
"SELECT sa.pk.personId, sa.pk.activityId from StarredActivity sa, Activity a"
+ " WHERE sa.pk.activityId = a.id AND a.recipientStreamScope.id = :groupStreamId")
.setParameter("groupStreamId", groupStreamId).list();
Long personId;
Long activityId;
for (Object[] row : queryResults)
{
personId = (Long) row[0];
activityId = (Long) row[1];
if (results.containsKey(personId))
{
results.get(personId).add(activityId);
}
else
{
HashSet<Long> set = new HashSet<Long>();
set.add(activityId);
results.put(personId, set);
}
}
return results;
}
}