//The persistence engine will send a variety of commands to the configured InstanceStore,
//such as CreateWorkflowOwnerCommand, SaveWorkflowCommand, and LoadWorkflowCommand.
//This method is where we will handle those commands
protected override IAsyncResult BeginTryCommand(InstancePersistenceContext context, InstancePersistenceCommand command, TimeSpan timeout, AsyncCallback callback, object state)
{
IDictionary<XName, InstanceValue> data;
//The CreateWorkflowOwner command instructs the instance store to create a new instance owner bound to the instanace handle
if (command is CreateWorkflowOwnerCommand)
{
context.BindInstanceOwner(this.ownerInstanceId, Guid.NewGuid());
}
//The SaveWorkflow command instructs the instance store to modify the instance bound to the instance handle or an instance key
else if (command is SaveWorkflowCommand)
{
var saveCommand = (SaveWorkflowCommand)command;
data = saveCommand.InstanceData;
this.Save(data);
}
//The LoadWorkflow command instructs the instance store to lock and load the instance bound to the identifier in the instance handle
else if (command is LoadWorkflowCommand)
{
var fileName = IoHelper.GetFileName(this.ownerInstanceId);
using (var inputStream = new FileStream(fileName, FileMode.Open))
{
data = LoadInstanceDataFromFile(inputStream);
//load the data into the persistence Context
context.LoadedInstance(InstanceState.Initialized, data, null, null, null);
}
}
return new CompletedAsyncResult<bool>(true, callback, state);
}
private bool LoadWorkflow(InstancePersistenceContext context, LoadWorkflowCommand command)
{
if (command.AcceptUninitializedInstance)
{
return false;
}
if (context.InstanceVersion == -1)
{
context.BindAcquiredLock(0);
}
Guid instanceId = context.InstanceView.InstanceId;
Guid instanceOwnerId = context.InstanceView.InstanceOwner.InstanceOwnerId;
IDictionary<XName, InstanceValue> instanceData = null;
IDictionary<XName, InstanceValue> instanceMetadata = null;
Dictionary<string, object> fullInstanceData = _stores.LoadWorkflowContext();
instanceData = this.DeserializePropertyBag((Dictionary<XName, object>)fullInstanceData["instanceData"]);
instanceMetadata = this.DeserializePropertyBag((Dictionary<XName, object>)fullInstanceData["instanceMetadata"]);
context.LoadedInstance(InstanceState.Initialized, instanceData, instanceMetadata, null, null);
return true;
}
private void SharedLoadWorkflow(InstancePersistenceContext context,
Guid instanceId)
{
if(instanceId != Guid.Empty)
{
IDictionary<XName, InstanceValue> instanceData;
IDictionary<XName, InstanceValue> instanceMetadata;
_dataStore.LoadInstance(instanceId,
out instanceData, out instanceMetadata);
if(context.InstanceView.InstanceId == Guid.Empty)
{
context.BindInstance(instanceId);
}
context.LoadedInstance(InstanceState.Initialized,
instanceData, instanceMetadata, null, null);
}
else
{
throw new InstanceNotReadyException(
String.Format("Unable to load instance: {0}", instanceId));
}
}
/// <summary>
/// The begin try command.
/// </summary>
/// <param name="context">The context.</param>
/// <param name="command">The command.</param>
/// <param name="timeout">The timeout.</param>
/// <param name="callback">The callback.</param>
/// <param name="state">The state.</param>
/// <returns>The <see cref="IAsyncResult" />.</returns>
/// <exception cref="SystemFailureException">Error processing message.</exception>
protected override IAsyncResult BeginTryCommand(
InstancePersistenceContext context,
InstancePersistenceCommand command,
TimeSpan timeout,
AsyncCallback callback,
object state)
{
lock (LocalLock)
{
if (command is CreateWorkflowOwnerCommand)
{
context.BindInstanceOwner(this.ownerInstanceId, Guid.NewGuid());
}
else
{
var saveWorkflowCommand = command as SaveWorkflowCommand;
if (saveWorkflowCommand != null)
{
this.SaveInstanceData(saveWorkflowCommand.InstanceData);
}
else if (command is LoadWorkflowCommand)
{
try
{
var instanceData = this.unstructuredStorageRepository.GetById(
"WorkflowInstanceStoreData",
this.ownerInstanceId.ToString());
var deserializedData = DeserializeData(instanceData.Payload.Combine());
context.LoadedInstance(InstanceState.Initialized, deserializedData, null, null, null);
}
catch (Exception exception)
{
throw;
}
}
}
return new CompletedAsyncResult<bool>(true, callback, state);
}
}
private Exception ProcessLoadWorkflow(
InstancePersistenceContext context,
LoadWorkflowCommand command)
{
try
{
if(command.AcceptUninitializedInstance)
{
context.LoadedInstance(InstanceState.Uninitialized,
null, null, null, null);
}
else
{
SharedLoadWorkflow(context, context.InstanceView.InstanceId);
}
return null;
}
catch(InstancePersistenceException exception)
{
Console.WriteLine(
// ReSharper disable LocalizableElement
"ProcessLoadWorkflow exception: {0}",
// ReSharper restore LocalizableElement
exception.Message);
return exception;
}
}