/// <summary>
/// Expands the view to use a time bound window. TimeInMillis bound windows are sliding windows that extend the
/// specified time interval into the past based on the system time. Provide a time period as parameter.
/// <para/>
/// If batch is specified, then the window buffers events (tumbling window) and releases them
/// after the given time interval has occurred.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="esperQuery">The esper query.</param>
/// <param name="seconds">The seconds.</param>
/// <param name="batched">if set to <c>true</c> [batched].</param>
/// <returns></returns>
public static EsperQuery <T> WithDuration <T>(this EsperQuery <T> esperQuery, int seconds, bool batched = false)
{
return(WithDuration(esperQuery, TimeSpan.FromSeconds(seconds), batched));
}
/// <summary>
/// Expands the view to use a time-accumulating. This data window view is a specialized moving (sliding)
/// time window that differs from the regular time window in that it accumulates events until no more events
/// arrive within a given time interval, and only then releases the accumulated events as a remove stream.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="esperQuery">The esper query.</param>
/// <param name="timeSpan">The time span.</param>
/// <returns></returns>
public static EsperQuery <T> WithAccumlation <T>(this EsperQuery <T> esperQuery, TimeSpan timeSpan)
{
var timePeriodExpression = timeSpan.ToTimePeriodExpression();
return(esperQuery.FilterView(() => View.Create("time_accum", timePeriodExpression)));
}
/// <summary>
/// Expands the view to keep events (tumbling window) until the given expression is satisfied.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="esperQuery">The esper query.</param>
/// <param name="expression">The expression.</param>
/// <returns></returns>
public static EsperQuery <T> KeepUntil <T>(this EsperQuery <T> esperQuery, System.Linq.Expressions.Expression <Func <T, bool> > expression)
{
return(esperQuery.FilterView(() => View.Create("win", "expr_batch", LinqToSoda.LinqToSodaExpression(expression))));
}
/// <summary>
/// Expands the view to keep all events. The view does not remove events from the
/// data window, unless used with a named window and the on delete clause.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="esperQuery">The esper query.</param>
/// <returns></returns>
public static EsperQuery <T> KeepAll <T>(this EsperQuery <T> esperQuery)
{
return(esperQuery.FilterView(() => View.Create("win", "keepall")));
}
/// <summary>
/// Expands the view to keep events that occur within the specified duration.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="esperQuery">The esper query.</param>
/// <param name="duration">The duration.</param>
/// <returns></returns>
public static EsperQuery <T> KeepFirst <T>(this EsperQuery <T> esperQuery, TimeSpan duration)
{
var timePeriodExpression = duration.ToTimePeriodExpression();
return(esperQuery.FilterView(() => View.Create("win", "firsttime", timePeriodExpression)));
}
/// <summary>
/// Expands the view to keep the first Count events.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="esperQuery">The esper query.</param>
/// <param name="length">The length.</param>
/// <returns></returns>
public static EsperQuery <T> KeepFirst <T>(this EsperQuery <T> esperQuery, int length)
{
return(esperQuery.FilterView(() => View.Create("win", "firstlength", new ConstantExpression(length))));
}
/// <summary>
/// Creates a window.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="serviceProvider">The service provider.</param>
/// <param name="windowName">Name of the window.</param>
/// <param name="view">The view.</param>
/// <param name="esperQuery">The esper query.</param>
/// <returns></returns>
public static EPStatement CreateWindow <T>(this EPServiceProvider serviceProvider, string windowName, View view, EsperQuery <T> esperQuery)
{
return(CreateWindow(serviceProvider, windowName, view, esperQuery, null));
}
/// <summary>
/// Selects the specified "item" from the esper query.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="esperQuery">The esper query.</param>
/// <returns></returns>
public static DisposableObservableCollection <T> Select <T>(this EsperQuery <T> esperQuery)
{
esperQuery.Compile();
return(esperQuery.Statement.AsObservableCollection <T>(true));
}
/// <summary>
/// Generates a view that orders events that arrive out-of-order, using timestamp-values
/// provided by an expression, and by comparing that timestamp value to engine system time.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="esperQuery">The esper query.</param>
/// <param name="property">The property to use for the timestamp.</param>
/// <param name="timePeriod">the time period specifying the time interval that an arriving event should maximally be held, in order to consider older events arriving at a later time</param>
/// <returns></returns>
/// <exception cref="System.ArgumentException">at least one property must be provided</exception>
public static EsperQuery <T> TimeOrdered <T>(this EsperQuery <T> esperQuery, string property, TimeSpan timePeriod)
{
return(esperQuery.FilterView(() => View.Create("ext", "time_order",
new PropertyValueExpression(property),
timePeriod.ToTimePeriodExpression())));
}
