/// <summary>
/// Attempt to retrieve an existing saga instance identified by the specified <paramref name="type"/> and <paramref name="id"/>.
/// </summary>
/// <param name="type">The type of saga to be retrieved.</param>
/// <param name="id">The correlation id of the saga to be retrieved.</param>
/// <param name="saga">The <see cref="Saga"/> instance if found; otherwise <value>null</value>.</param>
public Boolean TryGetSaga(Type type, Guid id, out Saga saga)
{
var result = sagaStore.TryGetSaga(type, id, out saga);
statistics.IncrementQueryCount();
return(result);
}
/// <summary>
/// Get or create the target saga instance.
/// </summary>
/// <param name="sagaType">The saga type.</param>
/// <param name="sagaId">The saga correlation id.</param>
/// <param name="e">The event instance to handle.</param>
private Saga GetOrCreateSaga(Type sagaType, Guid sagaId, Event e)
{
Saga saga;
if (!sagaStore.TryGetSaga(sagaType, sagaId, out saga) && sagaMetadata.CanStartWith(e.GetType()))
{
saga = sagaStore.CreateSaga(sagaType, sagaId);
}
return(saga);
}
/// <summary>
/// Attempt to retrieve an existing saga instance identified by the specified <paramref name="type"/> and <paramref name="id"/>.
/// </summary>
/// <param name="type">The type of saga to be retrieved.</param>
/// <param name="id">The correlation id of the saga to be retrieved.</param>
/// <param name="saga">The <see cref="Saga"/> instance if found; otherwise <value>null</value>.</param>
public Boolean TryGetSaga(Type type, Guid id, out Saga saga)
{
Boolean result;
InvokePreGetHooks(type, id);
result = sagaStore.TryGetSaga(type, id, out saga);
InvokePostGetHooks(saga);
return(result);
}
/// <summary>
/// Attempt to retrieve an existing saga instance identified by the specified <paramref name="type"/> and <paramref name="id"/>.
/// </summary>
/// <param name="type">The type of saga to be retrieved.</param>
/// <param name="id">The correlation id of the saga to be retrieved.</param>
/// <param name="saga">The <see cref="Saga"/> instance if found; otherwise <value>null</value>.</param>
public Boolean TryGetSaga(Type type, Guid id, out Saga saga)
{
Verify.NotNull(type, nameof(type));
var key = String.Concat(type.GetFullNameWithAssembly(), "-", id);
using (var sagaLock = new SagaLock(type, id))
{
sagaLock.Aquire();
//NOTE: We do not want to cache a NULL saga reference, thus explicitly check for existance and add to cache if instance found.
saga = (Saga)memoryCache.Get(key);
if (saga == null && sagaStore.TryGetSaga(type, id, out saga))
{
memoryCache.Add(key, saga, CreateCacheItemPolicy());
}
}
//NOTE: Given that saga state is modified during `Handling`, we must always return a copy of the cached instance.
return((saga == null ? null : saga = saga.Copy()) != null);
}