Class CallSlot

Represents a class that is immediately returned after transport sends RequestMsg. This class provides CallStatus and RequestID properties where the later is used to match the incoming ResponseMsg. CallSlots are kinds of "spirit-less" mailboxes that keep state about the call, but do not posess any threads/call events. Working with CallSlots from calling code's existing thread of execution is the most efficient way of working with Glue (in high load cases), as it does not create extra object instances (tasks do) for asynchronous coordination and continuation. It is possible to obtain an instance of CallSlot.AsTask in which case that instance is registered with the framework-internal reactor so task does complete normally even on timeout, however, in high-throughput apps (10K+ calls per second) this method is not the most efficient one as it allocates additional objects (task, list entry etc.) that eventually increase GC load for long runs. Note: A 3.2 Ghz 4-Core I7 server with 8Gb of ram can easily handle 40K 2-way calls a second (given little business server logic and simple payload). See also: CallReactor class

Inheritance

System.Object

CallSlot

Inherited Members

System.Object.Equals(System.Object, System.Object)

System.Object.GetType()

System.Object.MemberwiseClone()

System.Object.ReferenceEquals(System.Object, System.Object)

Namespace: NFX.Glue

Assembly: NFX.dll

Syntax

public sealed class CallSlot

Constructors

CallSlot(ClientEndPoint, ClientTransport, RequestMsg, CallStatus, Int32)

INTERNAL METHOD. Developers do not call! This constructor is used by an Async binding that delivers response after call slot was created

Declaration

public CallSlot(ClientEndPoint client, ClientTransport clientTransport, RequestMsg request, CallStatus status, int timeoutMs = 0)

Parameters

Type	Name	Description
ClientEndPoint	client
ClientTransport	clientTransport
RequestMsg	request
CallStatus	status
System.Int32	timeoutMs

CallSlot(ClientEndPoint, ClientTransport, Int64, DateTime, RequestMsg, ResponseMsg, Int32)

INTERNAL METHOD. Developers do not call! This constructor is used by a synchronous binding that delivers response right after sending it. ONLY for OneWayCall = false

Declaration

public CallSlot(ClientEndPoint client, ClientTransport clientTransport, long actualStartTimeTicks, DateTime actualStartTimeUtc, RequestMsg request, ResponseMsg response, int timeoutMs)

Parameters

Type	Name	Description
ClientEndPoint	client
ClientTransport	clientTransport
System.Int64	actualStartTimeTicks
System.DateTime	actualStartTimeUtc
RequestMsg	request
ResponseMsg	response
System.Int32	timeoutMs

Fields

DEFAULT_TIMEOUT_MS

Declaration

public const int DEFAULT_TIMEOUT_MS = 20000

Field Value

Type	Description
System.Int32

Properties

AsTask

Gets the CallSlot instance as a task that gets completed either instantly for one-way calls or when result arrives or timeout happens. The returned task never gets canceled

Declaration

public Task<CallSlot> AsTask { get; }

Property Value

Type	Description
System.Threading.Tasks.Task<CallSlot>

Available

Returns true when response has come and available so no blocking will occur when reading response. This is a non-blocking call. Always returns true for operations marked as [OneWay]

Declaration

public bool Available { get; }

Property Value

Type	Description
System.Boolean

CallContext

General-purpose property that clients can use for attaching an arbitrary context to this instance. This property has no use in the framework

Declaration

public object CallContext { get; set; }

Property Value

Type	Description
System.Object

CallStatus

Returns current call status. Timeout is returned when response has not arrived from the other side in alotted time. This is a non-blocking call

Declaration

public CallStatus CallStatus { get; }

Property Value

Type	Description
CallStatus

Client

Returns client endpoint that initiated this call

Declaration

public ClientEndPoint Client { get; }

Property Value

Type	Description
ClientEndPoint

ClientTransport

Returns client transport that this instance is originated from

Declaration

public ClientTransport ClientTransport { get; }

Property Value

Type	Description
ClientTransport

DispatchErrorMessage

Optionally returns reason of the dispatch message failure

Declaration

public string DispatchErrorMessage { get; }

Property Value

Type	Description
System.String

OneWay

Indicates that this call does not expect a response message from the server side

Declaration

public bool OneWay { get; }

Property Value

Type	Description
System.Boolean

RequestID

Returns request ID for the request that was sent and generated this slot instance

Declaration

public FID RequestID { get; }

Property Value

Type	Description
FID

ResponseMsg

Blocks until response comes or timeout happens. Response message inspection happens in the context of a calling thread

Declaration

public ResponseMsg ResponseMsg { get; }

Property Value

Type	Description
ResponseMsg

StartTime

Returns UTC timestamp of call initiation

Declaration

public DateTime StartTime { get; }

Property Value

Type	Description
System.DateTime

StatRoundtripEndTimeTicks

When binding's MeasureStatTimes enabled, returns the operation end (when response arrives) tick count

Declaration

public long StatRoundtripEndTimeTicks { get; }

Property Value

Type	Description
System.Int64

StatRoundtripTimeKey

When binding's MeasureStatTimes enabled, returns the name of the stat key

Declaration

public string StatRoundtripTimeKey { get; }

Property Value

Type	Description
System.String

StatStartTimeTicks

When binding's MeasureStatTimes enabled, returns the operation start tick count

Declaration

public long StatStartTimeTicks { get; }

Property Value

Type	Description
System.Int64

TimeoutMs

Returns timeout for this instance

Declaration

public int TimeoutMs { get; }

Property Value

Type	Description
System.Int32

Methods

AsTaskReturning<TCallResult>()

Creates a wrapper task around CallSlot.AsTask and returns CallSlot.GetValue() as TCallResult-returning Task. Note: the created wrapper task is not cached

Declaration

public Task<TCallResult> AsTaskReturning<TCallResult>()

Returns

Type	Description
System.Threading.Tasks.Task<TCallResult>

Type Parameters

Name	Description
TCallResult

AsTaskReturningVoid()

Creates a wrapper task around CallSlot.AsTask and returns CallSlot.CheckVoidValue() Note: the created wrapper task is not cached

Declaration

public Task AsTaskReturningVoid()

Returns

Type	Description
System.Threading.Tasks.Task

CheckVoidValue()

Checks for a valid void value returned from the other side, that is - gets the response message and checks it for errors, throwing RemoteError exception if one came from server. Accessing this property blocks calling thread until either ResponseMsg arrives or timeout expires. Check 'Available' property not to block. Accessing this method for [OneWay] methods throws.

Declaration

public void CheckVoidValue()

Equals(Object)

Declaration

public override bool Equals(object obj)

Parameters

Type	Name	Description
System.Object	obj

Returns

Type	Description
System.Boolean

Overrides

System.Object.Equals(System.Object)

GetHashCode()

Declaration

public override int GetHashCode()

Returns

Type	Description
System.Int32

Overrides

System.Object.GetHashCode()

GetValue<T>()

Returns a value from the other side, that is - gets the response message and checks it for errors, throwing RemoteError exception if one came from server. Accessing this property blocks calling thread until either ResponseMsg arrives or timeout expires. Check 'Available' property not to block. Accessing this method for [OneWay] methods throws.