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AbstractFlushingEventListener.cs
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AbstractFlushingEventListener.cs
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using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using NHibernate.Action;
using NHibernate.Collection;
using NHibernate.Engine;
using NHibernate.Impl;
using NHibernate.Persister.Entity;
using NHibernate.Util;
namespace NHibernate.Event.Default
{
/// <summary>
/// A convenience base class for listeners whose functionality results in flushing.
/// </summary>
[Serializable]
public abstract partial class AbstractFlushingEventListener
{
private static readonly INHibernateLogger log = NHibernateLogger.For(typeof (AbstractFlushingEventListener));
protected virtual object Anything
{
get { return null; }
}
protected virtual CascadingAction CascadingAction
{
get { return CascadingAction.SaveUpdate; }
}
/// <summary>
/// Coordinates the processing necessary to get things ready for executions
/// as db calls by preparing the session caches and moving the appropriate
/// entities and collections to their respective execution queues.
/// </summary>
/// <param name="event">The flush event.</param>
protected virtual void FlushEverythingToExecutions(FlushEvent @event)
{
log.Debug("flushing session");
IEventSource session = @event.Session;
IPersistenceContext persistenceContext = session.PersistenceContext;
session.Interceptor.PreFlush((ICollection) persistenceContext.EntitiesByKey.Values);
PrepareEntityFlushes(session);
// we could move this inside if we wanted to
// tolerate collection initializations during
// collection dirty checking:
PrepareCollectionFlushes(session);
// now, any collections that are initialized
// inside this block do not get updated - they
// are ignored until the next flush
persistenceContext.Flushing = true;
try
{
FlushEntities(@event);
FlushCollections(session);
}
finally
{
persistenceContext.Flushing = false;
}
//some statistics
if (log.IsDebugEnabled())
{
log.Debug(
"Flushed: {0} insertions, {1} updates, {2} deletions to {3} objects",
session.ActionQueue.InsertionsCount,
session.ActionQueue.UpdatesCount,
session.ActionQueue.DeletionsCount,
persistenceContext.EntityEntries.Count);
log.Debug(
"Flushed: {0} (re)creations, {1} updates, {2} removals to {3} collections",
session.ActionQueue.CollectionCreationsCount,
session.ActionQueue.CollectionUpdatesCount,
session.ActionQueue.CollectionRemovalsCount,
persistenceContext.CollectionEntries.Count);
new Printer(session.Factory).ToString(persistenceContext.EntitiesByKey.Values.ToArray());
}
}
protected virtual void FlushCollections(IEventSource session)
{
log.Debug("Processing unreferenced collections");
ICollection list = IdentityMap.Entries(session.PersistenceContext.CollectionEntries);
foreach (DictionaryEntry me in list)
{
CollectionEntry ce = (CollectionEntry) me.Value;
if (!ce.IsReached && !ce.IsIgnore)
{
Collections.ProcessUnreachableCollection((IPersistentCollection) me.Key, session);
}
}
// Schedule updates to collections:
log.Debug("Scheduling collection removes/(re)creates/updates");
list = IdentityMap.Entries(session.PersistenceContext.CollectionEntries);
ActionQueue actionQueue = session.ActionQueue;
foreach (DictionaryEntry me in list)
{
IPersistentCollection coll = (IPersistentCollection) me.Key;
CollectionEntry ce = (CollectionEntry) me.Value;
if (ce.IsDorecreate)
{
session.Interceptor.OnCollectionRecreate(coll, ce.CurrentKey);
actionQueue.AddAction(new CollectionRecreateAction(coll, ce.CurrentPersister, ce.CurrentKey, session));
}
if (ce.IsDoremove)
{
session.Interceptor.OnCollectionRemove(coll, ce.LoadedKey);
actionQueue.AddAction(
new CollectionRemoveAction(coll, ce.LoadedPersister, ce.LoadedKey, ce.IsSnapshotEmpty(coll), session));
}
if (ce.IsDoupdate)
{
session.Interceptor.OnCollectionUpdate(coll, ce.LoadedKey);
actionQueue.AddAction(
new CollectionUpdateAction(coll, ce.LoadedPersister, ce.LoadedKey, ce.IsSnapshotEmpty(coll), session));
}
}
actionQueue.SortCollectionActions();
}
// 1. detect any dirty entities
// 2. schedule any entity updates
// 3. search out any reachable collections
protected virtual void FlushEntities(FlushEvent @event)
{
log.Debug("Flushing entities and processing referenced collections");
// Among other things, updateReachables() will recursively load all
// collections that are moving roles. This might cause entities to
// be loaded.
// So this needs to be safe from concurrent modification problems.
// It is safe because of how IdentityMap implements entrySet()
IEventSource source = @event.Session;
ICollection list = IdentityMap.ConcurrentEntries(source.PersistenceContext.EntityEntries);
foreach (DictionaryEntry me in list)
{
// Update the status of the object and if necessary, schedule an update
EntityEntry entry = (EntityEntry) me.Value;
Status status = entry.Status;
if (status != Status.Loading && status != Status.Gone)
{
FlushEntityEvent entityEvent = new FlushEntityEvent(source, me.Key, entry);
IFlushEntityEventListener[] listeners = source.Listeners.FlushEntityEventListeners;
foreach (IFlushEntityEventListener listener in listeners)
{
listener.OnFlushEntity(entityEvent);
}
}
}
source.ActionQueue.SortActions();
}
// Initialize the flags of the CollectionEntry, including the dirty check.
protected virtual void PrepareCollectionFlushes(ISessionImplementor session)
{
// Initialize dirty flags for arrays + collections with composite elements
// and reset reached, doupdate, etc.
log.Debug("dirty checking collections");
ICollection list = IdentityMap.Entries(session.PersistenceContext.CollectionEntries);
foreach (DictionaryEntry entry in list)
{
((CollectionEntry) entry.Value).PreFlush((IPersistentCollection) entry.Key);
}
}
//process cascade save/update at the start of a flush to discover
//any newly referenced entity that must be passed to saveOrUpdate(),
//and also apply orphan delete
protected virtual void PrepareEntityFlushes(IEventSource session)
{
log.Debug("processing flush-time cascades");
ICollection list = IdentityMap.ConcurrentEntries(session.PersistenceContext.EntityEntries);
//safe from concurrent modification because of how entryList() is implemented on IdentityMap
foreach (DictionaryEntry me in list)
{
EntityEntry entry = (EntityEntry) me.Value;
Status status = entry.Status;
if (status == Status.Loaded || status == Status.Saving || status == Status.ReadOnly)
{
CascadeOnFlush(session, entry.Persister, me.Key, Anything);
}
}
}
protected virtual void CascadeOnFlush(IEventSource session, IEntityPersister persister, object key, object anything)
{
session.PersistenceContext.IncrementCascadeLevel();
try
{
new Cascade(CascadingAction, CascadePoint.BeforeFlush, session).CascadeOn(persister, key, anything);
}
finally
{
session.PersistenceContext.DecrementCascadeLevel();
}
}
/// <summary>
/// Execute all SQL and second-level cache updates, in a
/// special order so that foreign-key constraints cannot
/// be violated:
/// <list type="bullet">
/// <item> <description>Inserts, in the order they were performed</description> </item>
/// <item> <description>Updates</description> </item>
/// <item> <description>Deletion of collection elements</description> </item>
/// <item> <description>Insertion of collection elements</description> </item>
/// <item> <description>Deletes, in the order they were performed</description> </item>
/// </list>
/// </summary>
/// <param name="session">The session being flushed</param>
protected virtual void PerformExecutions(IEventSource session)
{
if (log.IsDebugEnabled())
{
log.Debug("executing flush");
}
try
{
session.ConnectionManager.FlushBeginning();
// IMPL NOTE : here we alter the flushing flag of the persistence context to allow
// during-flush callbacks more leniency in regards to initializing proxies and
// lazy collections during their processing.
// For more information, see HHH-2763 / NH-1882
session.PersistenceContext.Flushing = true;
// we need to lock the collection caches before
// executing entity inserts/updates in order to
// account for bidi associations
session.ActionQueue.PrepareActions();
session.ActionQueue.ExecuteActions();
}
catch (HibernateException he)
{
if (log.IsErrorEnabled())
{
log.Error(he, "Could not synchronize database state with session");
}
throw;
}
finally
{
session.PersistenceContext.Flushing = false;
session.ConnectionManager.FlushEnding();
}
}
/// <summary>
/// 1. Recreate the collection key -> collection map
/// 2. rebuild the collection entries
/// 3. call Interceptor.postFlush()
/// </summary>
protected virtual void PostFlush(ISessionImplementor session)
{
if (log.IsDebugEnabled())
{
log.Debug("post flush");
}
IPersistenceContext persistenceContext = session.PersistenceContext;
persistenceContext.CollectionsByKey.Clear();
persistenceContext.BatchFetchQueue.ClearSubselects();
//the database has changed now, so the subselect results need to be invalidated
// NH Different implementation: In NET an iterator is immutable;
// we need something to hold the persistent collection to remove, and it must be less intrusive as possible
IDictionary cEntries = persistenceContext.CollectionEntries;
List<IPersistentCollection> keysToRemove = new List<IPersistentCollection>(cEntries.Count);
foreach (DictionaryEntry me in cEntries)
{
CollectionEntry collectionEntry = (CollectionEntry) me.Value;
IPersistentCollection persistentCollection = (IPersistentCollection) me.Key;
collectionEntry.PostFlush(persistentCollection);
if (collectionEntry.LoadedPersister == null)
{
keysToRemove.Add(persistentCollection);
}
else
{
//otherwise recreate the mapping between the collection and its key
CollectionKey collectionKey =
new CollectionKey(collectionEntry.LoadedPersister, collectionEntry.LoadedKey);
persistenceContext.CollectionsByKey[collectionKey] = persistentCollection;
}
}
foreach (IPersistentCollection key in keysToRemove)
{
persistenceContext.CollectionEntries.Remove(key);
}
session.Interceptor.PostFlush((ICollection) persistenceContext.EntitiesByKey.Values);
}
}
}