/// <summary>Merges the temporary storage with the global storage.</summary>
/// <param name="dataSourceInfo">The parameter is not used.</param>
protected override void SaveChangesCore(DataSourceInfo dataSourceInfo)
{
MemoryStore <TEntity> memoryStore = this.SelectMemoryStore(dataSourceInfo);
try {
/* Make sure no one has access to the global and local storage */
memoryStore.EnterWriteLock();
this.temporaryStorageLock.EnterWriteLock();
/* First, check if all the updated entities still exist in the global storage */
Dictionary <int, TEntity> updatedEntities = new Dictionary <int, TEntity>();
foreach (TEntity entity in this.updateCache)
{
var storedEntity = memoryStore.Storage.Select((item, index) => new { Entity = item, Index = index })
.FirstOrDefault(a => a.Entity.RecordId == entity.RecordId);
if (storedEntity == null)
{
throw new InvalidOperationException(
string.Format(CultureInfo.CurrentCulture, "Cannot update entity {0} since it does not exist in the global storage", entity.RecordId));
}
else
{
updatedEntities.Add(storedEntity.Index, entity);
}
}
/* Then, check if all the deleted entities still exist in the global storage */
Dictionary <int, TEntity> deletedEntities = new Dictionary <int, TEntity>();
foreach (TEntity entity in this.deletionCache)
{
var storedEntity = memoryStore.Storage.Select((item, index) => new { Entity = item, Index = index })
.FirstOrDefault(a => a.Entity.RecordId == entity.RecordId);
if (storedEntity == null)
{
throw new InvalidOperationException(
string.Format(CultureInfo.CurrentCulture, "Cannot delete entity {0} since it does not exist in the global storage", entity.RecordId));
}
else
{
deletedEntities.Add(storedEntity.Index, entity);
}
}
/* All the pre-checks have been completed, start the saving */
/* First, perform the updates */
foreach (KeyValuePair <int, TEntity> updatedEntity in updatedEntities)
{
if (this.SelectCloneDataSourceItems(dataSourceInfo))
{
memoryStore.Storage[updatedEntity.Key] = ((ICloneable)updatedEntity.Value).Clone() as TEntity;
}
else
{
memoryStore.Storage[updatedEntity.Key] = updatedEntity.Value;
}
}
/* Then perform the deletions */
int iteration = 0;
foreach (KeyValuePair <int, TEntity> deletedEntity in deletedEntities.OrderBy(kvp => kvp.Key))
{
memoryStore.Storage.RemoveAt(deletedEntity.Key - iteration);
++iteration;
}
/* Then apply new identifiers to the new entities */
int startId = memoryStore.Storage.DefaultIfEmpty(new TEntity {
RecordId = 0
}).Max(t => t.RecordId) + 1;
this.ApplyIdentifiers(this.additionCache, startId);
/* Then add the added entities to the global storage */
foreach (TEntity addedEntity in this.additionCache)
{
if (this.SelectCloneDataSourceItems(dataSourceInfo))
{
memoryStore.Storage.Add(((ICloneable)addedEntity).Clone() as TEntity);
}
else
{
memoryStore.Storage.Add(addedEntity);
}
}
/* Finally, clear the local storage */
this.additionCache.Clear();
this.updateCache.Clear();
this.deletionCache.Clear();
}
finally {
memoryStore.ExitWriteLock();
this.temporaryStorageLock.ExitWriteLock();
}
}
/// <summary>Updates a collection of entities in the repository. Depending on the status of each entity, it is updated in the addition-cache or
/// it is added to the update-cache.</summary>
/// <param name="entities">The entities that contain the updated values.</param>
/// <param name="dataSourceInfo">Information about the data source that may not have been set at an earlier stage. This parameter is not used.
/// </param>
/// <returns>The entities as they are stored in the repository.</returns>
protected override IEnumerable <TEntity> UpdateEntitiesCore(IEnumerable <TEntity> entities, DataSourceInfo dataSourceInfo)
{
if (entities.Any(e => e.RecordId == 0))
{
throw new InvalidOperationException("Cannot update an entity whose identifier is zero.");
}
EntityEqualityComparer <TEntity> entityComparer = new EntityEqualityComparer <TEntity>();
MemoryStore <TEntity> memoryStore = this.SelectMemoryStore(dataSourceInfo);
IEnumerable <TEntity> addedEntities = entities.Where(e => e.RecordId < 0);
IEnumerable <TEntity> updatedEntities = entities.Where(e => e.RecordId > 0);
this.temporaryStorageLock.EnterWriteLock();
memoryStore.EnterReadLock();
/* Make a copy of the caches. That way, if any thing goes wrong all the changes can be made undone */
List <TEntity> tempAdditionCache = this.additionCache.ToList();
List <TEntity> tempUpdateCache = this.updateCache.ToList();
List <TEntity> tempDeletionCache = this.deletionCache.ToList();
List <TEntity> newlyAddedEntities = new List <TEntity>();
List <TEntity> currentUpdatedEntities = new List <TEntity>();
try {
foreach (TEntity addedEntity in addedEntities)
{
/* If the entity is marked for addition, update the entity in the addition cache */
if (tempAdditionCache.Contains(addedEntity, entityComparer))
{
int indexOfEntity = tempAdditionCache.IndexOf(addedEntity, entityComparer);
TEntity repositoryEntity = tempAdditionCache[indexOfEntity];
/* Copy the values of the updated entity into the cached entity */
repositoryEntity.CopyFrom(addedEntity);
newlyAddedEntities.Add(repositoryEntity);
}
else
{
throw new InvalidOperationException("Could not find the entity in the addition-cache.");
}
}
foreach (TEntity updatedEntity in updatedEntities)
{
if (memoryStore.Storage.Contains(updatedEntity, entityComparer))
{
/* If the entity is already marked for deletion, it can no longer be updated. */
if (tempDeletionCache.Contains(updatedEntity, entityComparer))
{
throw new InvalidOperationException("Cannot update the entity since it already marked for deletion.");
}
TEntity repositoryEntity;
if (tempUpdateCache.Contains(updatedEntity, entityComparer))
{
/* If the entity was already marked for update, replace it in the update cache */
int indexOfEntity = tempUpdateCache.IndexOf(updatedEntity, entityComparer);
repositoryEntity = tempUpdateCache[indexOfEntity];
/* Copy the values of the updated entity into the cached entity */
repositoryEntity.CopyFrom(updatedEntity);
}
else
{
/* Retrieve the original version of the entity from the storage */
TEntity originalEntity = memoryStore.Storage[memoryStore.Storage.IndexOf(updatedEntity, entityComparer)];
/* Create a copy of the original entity to avoid any unwanted updates of the original entity */
repositoryEntity = originalEntity.CreateCopyOrClone();
/* Copy the values of the updated entity into the (copy of) original entity */
repositoryEntity.CopyFrom(updatedEntity);
/* Store the updated entity in the update cache */
tempUpdateCache.Add(repositoryEntity);
}
currentUpdatedEntities.Add(repositoryEntity);
}
else
{
throw new InvalidOperationException("Could not find the entity in the internal cache.");
}
}
/* Replace the original caches to complete the 'transaction' */
this.additionCache = tempAdditionCache;
this.updateCache = tempUpdateCache;
this.deletionCache = tempDeletionCache;
if (this.SelectCloneDataSourceItems(dataSourceInfo))
{
return(newlyAddedEntities.Concat(currentUpdatedEntities).Select(entity => ((ICloneable)entity).Clone() as TEntity).ToList());
}
else
{
IEnumerable <TEntity> resultList = newlyAddedEntities.Concat(currentUpdatedEntities);
resultList.ForEach(entity => entities.Single(e => e.RecordId == entity.RecordId).CopyFrom(entity));
return(entities);
}
}
finally {
memoryStore.ExitReadLock();
if (this.temporaryStorageLock.IsWriteLockHeld)
{
this.temporaryStorageLock.ExitWriteLock();
}
}
}
/// <summary>Removes a collection of entities from the repository. Depending on the status of each entity, it is removed from the addition-cache
/// or it is added to the deletion-cache until it is saved using the <see cref="Repository{T}.SaveChanges()"/> method.</summary>
/// <param name="entities">The entities that must be removed.</param>
/// <param name="dataSourceInfo">Information about the data source that may not have been set at an earlier stage. This parameter is not used.
/// </param>
protected override void DeleteEntitiesCore(IEnumerable <TEntity> entities, DataSourceInfo dataSourceInfo)
{
if (entities.Any(e => e.RecordId == 0))
{
throw new InvalidOperationException("Cannot delete an entity whose identifier is zero.");
}
IEqualityComparer <TEntity> entityComparer = new EntityEqualityComparer <TEntity>();
MemoryStore <TEntity> memoryStore = this.SelectMemoryStore(dataSourceInfo);
this.temporaryStorageLock.EnterWriteLock();
memoryStore.EnterReadLock();
IEnumerable <TEntity> addedEntities = entities.Where(e => e.RecordId < 0);
IEnumerable <TEntity> existingEntities = entities.Where(e => e.RecordId > 0);
/* Make a copy of the caches. That way, if any thing goes wrong all the changes can be made undone */
List <TEntity> tempAdditionCache = this.additionCache.ToList();
List <TEntity> tempUpdateCache = this.updateCache.ToList();
List <TEntity> tempDeletionCache = this.deletionCache.ToList();
try {
foreach (TEntity addedEntity in addedEntities)
{
/* If the ID is negative, it should be marked for addition */
if (tempAdditionCache.Contains(addedEntity, entityComparer))
{
tempAdditionCache.Remove(addedEntity, entityComparer);
}
else
{
throw new InvalidOperationException("Could not find the entity in the memory.");
}
}
foreach (TEntity existingEntity in existingEntities)
{
/* If the entity was marked for update, remove that mark */
if (tempUpdateCache.Contains(existingEntity, entityComparer))
{
tempUpdateCache.Remove(existingEntity, entityComparer);
}
/* If the entity exists in the original data source and has not yet been marked for deletion, mark it now */
if (memoryStore.Storage.Contains(existingEntity, entityComparer))
{
if (!tempDeletionCache.Contains(existingEntity, entityComparer))
{
tempDeletionCache.Add(existingEntity);
}
else
{
throw new InvalidOperationException("Cannot delete the same entity more then once.");
}
}
else
{
throw new InvalidOperationException("Could not find the entity in the internal cache.");
}
}
/* Replace the original caches to complete the 'transaction' */
this.additionCache = tempAdditionCache;
this.updateCache = tempUpdateCache;
this.deletionCache = tempDeletionCache;
}
finally {
memoryStore.ExitReadLock();
if (this.temporaryStorageLock.IsWriteLockHeld)
{
this.temporaryStorageLock.ExitWriteLock();
}
}
}
/// <summary>Updates an entity in the storage.</summary>
/// <param name="entity">The entity that must be updated.</param>
/// <param name="dataSourceInfo">The parameter is not used.</param>
/// <returns>The updated entity.</returns>
protected override TEntity UpdateEntityCore(TEntity entity, DataSourceInfo dataSourceInfo)
{
if (entity.RecordId == 0)
{
throw new InvalidOperationException("Cannot update an entity whose identifier is zero.");
}
EntityEqualityComparer <TEntity> entityComparer = new EntityEqualityComparer <TEntity>();
MemoryStore <TEntity> memoryStore = this.SelectMemoryStore(dataSourceInfo);
try {
/* First search the temporary storage */
this.temporaryStorageLock.EnterWriteLock();
memoryStore.EnterReadLock();
if (entity.RecordId < 0)
{
if (this.additionCache.Contains(entity, entityComparer))
{
int indexOfEntity = this.additionCache.IndexOf(entity, entityComparer);
TEntity repositoryEntity = this.additionCache[indexOfEntity];
/* Copy the values of the updated entity into the cached entity */
repositoryEntity.CopyFrom(entity);
if (this.SelectCloneDataSourceItems(dataSourceInfo))
{
return(((ICloneable)repositoryEntity).Clone() as TEntity);
}
else
{
entity.CopyFrom(repositoryEntity);
return(entity);
}
}
else
{
throw new InvalidOperationException("Could not find the entity in the addition-cache.");
}
}
else
{
if (memoryStore.Storage.Contains(entity, entityComparer))
{
if (this.deletionCache.Contains(entity, entityComparer))
{
throw new InvalidOperationException("Cannot update the entity since it already marked for deletion.");
}
TEntity repositoryEntity;
if (this.updateCache.Contains(entity, entityComparer))
{
/* Retrieve the previous updated version of the entity from the cache */
int indexOfEntity = this.updateCache.IndexOf(entity, entityComparer);
repositoryEntity = this.updateCache[indexOfEntity];
/* Copy the values of the updated entity into the cached entity */
repositoryEntity.CopyFrom(entity);
}
else
{
/* Retrieve the original version of the entity from the storage */
TEntity originalEntity = memoryStore.Storage[memoryStore.Storage.IndexOf(entity, entityComparer)];
/* Create a copy of the original entity to avoid any unwanted updates of the original entity */
repositoryEntity = originalEntity.CreateCopyOrClone();
/* Copy the values of the updated entity into the (copy of) original entity */
repositoryEntity.CopyFrom(entity);
/* Store the updated entity in the update cache */
this.updateCache.Add(repositoryEntity);
}
/* Return an instance of TEntity that reflects the changes, but is disconnected from the instance that is stored in the cache
* (to avoid unwanted updates from outside the repository) */
if (this.SelectCloneDataSourceItems(dataSourceInfo))
{
return(((ICloneable)repositoryEntity).Clone() as TEntity);
}
else
{
entity.CopyFrom(repositoryEntity);
return(entity);
}
}
else
{
throw new InvalidOperationException("Could not find the entity in the internal cache.");
}
}
}
finally {
memoryStore.ExitReadLock();
if (this.temporaryStorageLock.IsWriteLockHeld)
{
this.temporaryStorageLock.ExitWriteLock();
}
}
}
/// <summary>Deletes the entity from the storage.</summary>
/// <param name="entity">The entity that must be removed.</param>
/// <param name="dataSourceInfo">The parameter is not used.</param>
protected override void DeleteEntityCore(TEntity entity, DataSourceInfo dataSourceInfo)
{
if (entity.RecordId == 0)
{
throw new InvalidOperationException("Cannot delete an entity whose identifier is zero.");
}
IEqualityComparer <TEntity> entityComparer = new EntityEqualityComparer <TEntity>();
MemoryStore <TEntity> memoryStore = this.SelectMemoryStore(dataSourceInfo);
try {
/* First search the temporary storage */
this.temporaryStorageLock.EnterWriteLock();
memoryStore.EnterReadLock();
if (entity.RecordId < 0)
{
/* If the ID is negative, it should be marked for addition */
if (this.additionCache.Contains(entity, entityComparer))
{
this.additionCache.Remove(entity, entityComparer);
}
else
{
throw new InvalidOperationException("Could not find the entity in the memory.");
}
}
else
{
/* If the entity was marked for update, remove that mark */
if (this.updateCache.Contains(entity, entityComparer))
{
this.updateCache.Remove(entity, entityComparer);
}
/* If the entity exists in the original data source and has not yet been marked for deletion, mark it now */
if (memoryStore.Storage.Contains(entity, entityComparer))
{
if (!this.deletionCache.Contains(entity, entityComparer))
{
this.deletionCache.Add(entity);
}
else
{
throw new InvalidOperationException("Cannot delete the same entity more then once.");
}
}
else
{
throw new InvalidOperationException("Could not find the entity in the memory.");
}
}
}
finally {
memoryStore.ExitReadLock();
if (this.temporaryStorageLock.IsWriteLockHeld)
{
this.temporaryStorageLock.ExitWriteLock();
}
}
}
