IMultiTopic is a specialization of ITopicDescription that allows subscriptions to combine, filter and/or rearrange data coming from several Topics. More...

Inheritance diagram for DDS.IMultiTopic:

Collaboration diagram for DDS.IMultiTopic:

Public Member Functions
ReturnCode	GetExpressionParameters (ref string[] expressionParameters)

ReturnCode	SetExpressionParameters (params string[] expressionParameters)

Properties
string	SubscriptionExpression `[get]`

Properties inherited from DDS.ITopicDescription
string	Name `[get]`
	Gets the name of this ITopicDescription. More...

IDomainParticipant	Participant `[get]`
	Gets the IDomainParticipant associated with this ITopicDescription. More...

string	TypeName `[get]`
	Gets the name of the registered data type that is associated with this ITopicDescription. More...

Detailed Description

IMultiTopic is a specialization of ITopicDescription that allows subscriptions to combine, filter and/or rearrange data coming from several Topics.

Note: The IMultiTopic is not yet implemented. It is scheduled for a future release.

IMultiTopic allows a more sophisticated subscription that can select and combine data received from multiple Topics into a single data type (specified by the inherited typeName). The data will then be filtered (selection) and possibly re-arranged (aggregation and/or projection) according to an SQL expression with parameters to adapt the filter clause.

Definition at line 2545 of file DdsDcpsInterfaces.cs.

Member Function Documentation

◆ GetExpressionParameters()

ReturnCode DDS.IMultiTopic.GetExpressionParameters ( ref string [] expressionParameters )

Note: This operation is not yet implemented. It is scheduled for a future release. This operation obtains the expression parameters associated with the IMultiTopic.

This operation obtains the expression parameters associated with the IIMultiTopic. That is, the parameters specified on the last successful cal l to SetExpressionParameters, or if SetExpressionParameters was never called, the parameters specified when the MultiTopic was created. The resulting reference holds a sequence of strings with the values of the parameters used in the SQL expression (i.e., the n tokens in the expression). The number of parameters in the result sequence will exactly match the number of n tokens in the filter expression associated with the MultiTopic.

Parameters

expressionParameters A sequence of strings with the parameter value used in the SQL expression.

Returns

The possible return codes are:

DDS.ReturnCode Ok - the existing set of expression parameters applied to this IMultiTopic has successfully been copied into the specified expressionParameters parameter.
DDS.ReturnCode Error - An internal error has occured.
DDS.ReturnCode AlreadyDeleted - The IIMultiTopic has already been deleted.
DDS.ReturnCode OutOfResources - The DDS ran out of resources to complete this operation.

◆ SetExpressionParameters()

ReturnCode DDS.IMultiTopic.SetExpressionParameters ( params string [] expressionParameters )

Note: This operation is not yet implemented. It is scheduled for a future release.

This operation changes the expression parameters associated with the IMultiTopic. The parameter expressionParameters is a handle to a sequence of strings with the parameters used in the SQL expression. The number of parameters in expressionParameters must exactly match the number of n tokens in the subscription expression associated with the IMultiTopic. This is the subscription expression specified when the IMultiTopic was created.

Parameters

expressionParameters A sequence of strings with the parameter value used in the SQL expression.

Returns

The possible return codes are:

DDS.ReturnCode Ok - The new expression parameters are set.
DDS.ReturnCode Error - An internal error has occured.
DDS.ReturnCode AlreadyDeleted - The IMultiTopic has already been deleted.
DDS.ReturnCode OutOfResources - The DDS ran out of resources to complete this operation.
DDS.ReturnCode BadParameter - The number of parameters in expressionParameters does not match the number of tokens in the expression for this IMultiTopic or one of the parameters is an illegal parameter.

Property Documentation

◆ SubscriptionExpression

string DDS.IMultiTopic.SubscriptionExpression

get

Note: This operation is not yet implemented. It is scheduled for a future release. This operation returns the subscription expression associated with the IMultiTopic.

This operation returns the subscription expression associated with the IMultiTopic. That is, the expression specified when the IMultiTopic was created. The subscription expression result is a string that specifies the criteria to select the data samples of interest. In other words, it identifies the selection and rearrangement of data from the associated ITopics. It is an SQL expression where the SELECT clause provides the fields to be kept, the FROM part provides the names of the Topics that are searched for those fields, and the WHERE clause gives the content filter. The ITopics combined may have different types but they are restricted in that the type of the fields used for the NATURAL JOIN operation must be the same

Definition at line 2562 of file DdsDcpsInterfaces.cs.

The documentation for this interface was generated from the following file:

src/api/dcps/sacs/code/DDS/DdsDcpsInterfaces.cs