Class DXFeed

Namespace

DxFeed.Graal.Net.Api

Assembly

DxFeed.Graal.Net.dll

Main entry class for dxFeed API. This class is a wrapper for FeedNative.
Read it first Javadoc.

public class DXFeed

Inheritance

object

DXFeed

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Methods

CreateSubscription(IEnumerable<Type>)

Creates new subscription for a list of event types that is attached to this feed.

public DXFeedSubscription CreateSubscription(IEnumerable<Type> eventTypes)

Parameters

eventTypes IEnumerable<Type>

The list of event types. Events types must be implement IEventType and have EventCodeAttribute.

Returns

DXFeedSubscription

The created subscription.

Exceptions

ArgumentException

If one on the specified Type has no EventCodeAttribute.

CreateSubscription(params Type[])

Creates new subscription for a list of event types that is attached to this feed.

public DXFeedSubscription CreateSubscription(params Type[] eventTypes)

Parameters

eventTypes Type[]

The list of event types. Events types must be implement IEventType and have EventCodeAttribute.

Returns

DXFeedSubscription

The created DXFeedSubscription.

Exceptions

ArgumentException

If one on the specified Type has no EventCodeAttribute.

GetInstance()

Gets a default application-wide singleton instance of feed. Most applications use only a single data-source and should rely on this method to get one.

public static DXFeed GetInstance()

Returns

DXFeed

The DXFeed.

GetLasEventIfSubscribed<TE>(object)

Returns the last event for the specified event type and symbol if there is a subscription for it. This method works only for event types that implement ILastingEvent marker interface. This method does not make any remote calls to the uplink data provider. It just retrieves last received event from the local cache of this feed. The events are stored in the cache only if there is some attached DXFeedSubscription that is subscribed to the corresponding event type and symbol. The subscription can also be permanently defined using DXEndpoint properties. All subscription does not count for that purpose. If there is no subscription, then this method returns null.

If there is a subscription, but the event has not arrived from the uplink data provider, this method returns an non-initialized event object: its GetLastEvent<TE>(TE) property is set to the requested symbol, but all the other properties have their default values.

Use GetLastEventAsync<T>(object, CancellationToken) method if an event needs to be requested in the absence of subscription.

Note, that this method does not work when DXEndpoint was created with StreamFeed role (never fills in the event).

public TE? GetLasEventIfSubscribed<TE>(object symbol) where TE : ILastingEvent

Parameters

symbol object

The symbol.

Returns

TE

The event or null if there is no subscription for the specified event type and symbol.

Type Parameters

TE

The event type.

GetLastEventAsync<T>(object, CancellationToken)

Requests the last event for the specified event type and symbol. This method works only for event types that implement ILastingEvent marker interface. This method requests the data from the uplink data provider, creates new event of the specified event type, and Result the resulting task with this event.

public Task<T> GetLastEventAsync<T>(object symbol, CancellationToken token = default) where T : ILastingEvent

Parameters

symbol object

The symbol.

token CancellationToken

The cancellation token.

Returns

Task<T>

The task for the result of the request.

Type Parameters

T

The type of event.

GetLastEvent<TE>(TE)

Returns the last event for the specified event instance. This method works only for event types that implement ILastingEvent marker interface. This method does not make any remote calls to the uplink data provider. It just retrieves last received event from the local cache of this feed. The events are stored in the cache only if there is some attached DXFeedSubscription that is subscribed to the corresponding symbol and event type. All subscription does not count for that purpose.

Use GetLastEventAsync<T>(object, CancellationToken) method if an event needs to be requested in the absence of subscription.

This method fills in the values for the last event into the event argument. If the last event is not available for any reason (no subscription, no connection to uplink, etc). then the event object is not changed. This method always returns the same event instance that is passed to it as an argument.

This method provides no way to distinguish a case when there is no subscription from the case when there is a subscription, but the event data have not arrived yet. It is recommended to use GetLasEventIfSubscribed<TE>(object) method instead of this GetLastEvent method to fail-fast in case when the subscription was supposed to be set by the logic of the code, since GetLasEventIfSubscribed<TE>(object) method returns null when there is no subscription.

Note, that this method does not work when DXEndpoint was created with StreamFeed role (never fills in the event).

public TE GetLastEvent<TE>(TE e) where TE : ILastingEvent

Parameters

e TE

The event.

Returns

TE

The same event.

Type Parameters

TE

The type of event.

GetLastEvents<TE>(IList<TE>)

Returns the last events for the specified list of event instances. This is a bulk version of GetLastEvent<TE>(TE) method.

Note, that this method does not work when DXEndpoint was created with StreamFeed role (never fills in the event).

public IList<TE> GetLastEvents<TE>(IList<TE> events) where TE : ILastingEvent

Parameters

events IList<TE>

The collection of events.

Returns

IList<TE>

The same collection of events.

Type Parameters

TE

The type of event.

GetTimeSeriesAsync<T>(object, long, long, CancellationToken)

Requests time series of events for the specified event type, symbol, and a range of time. This method works only for event types that implement ITimeSeriesEvent interface. his method requests the data from the the uplink data provider, creates a list of events of the specified event type, and Result the resulting task with this list.

public Task<IEnumerable<T>> GetTimeSeriesAsync<T>(object symbol, long from, long to, CancellationToken token = default) where T : ITimeSeriesEvent

Parameters

symbol object

The symbol.

from long

The time, inclusive, to request events from Time.

to long

The time, inclusive, to request events from Time. Use long.MaxValue to retrieve events without an upper limit on time.

token CancellationToken

The cancellation token.

Returns

Task<IEnumerable<T>>

The task for the result of the request.

Type Parameters

T

The event type.