IContentFilteredTopic is a specialization of ITopicDescription that allows for content based subscriptions. More...

Inheritance diagram for DDS.IContentFilteredTopic:

Collaboration diagram for DDS.IContentFilteredTopic:

Public Member Functions
ReturnCode	GetExpressionParameters (ref string[] expressionParameters)
	This operation obtains the expression parameters associated with the IContentFilteredTopic. More...

string	GetFilterExpression ()
	This operation returns the filterExpression associated with the IContentFilteredTopic. More...

ReturnCode	SetExpressionParameters (params string[] expressionParameters)
	This operation changes the expression parameters associated with the IContentFilteredTopic. More...

Properties
ITopic	RelatedTopic `[get]`
	This property returns the ITopic associated with the IContentFilteredTopic. More...

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

IContentFilteredTopic is a specialization of ITopicDescription that allows for content based subscriptions.

IContentFilteredTopic describes a more sophisticated subscription that indicates that the ISubscriber does not necessarily want to see all values of each instance published under the ITopic. Rather, it only wants to see the values whose contents satisfy certain criteria. Therefore this class must be used to request content-based subscriptions. The selection of the content is done using the SQL based filter with parameters to adapt the filter clause.

Definition at line 2447 of file DdsDcpsInterfaces.cs.

Member Function Documentation

◆ GetExpressionParameters()

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

This operation obtains the expression parameters associated with the IContentFilteredTopic.

This operation obtains the expression parameters associated with the IContentFilteredTopic. That is, the parameters specified on the last successful call to SetExpressionParameters, or if SetExpressionParameters was never called, the parameters specified when the IContentFilteredTopic was created.

The resulting reference holds a sequence of strings with 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 IContentFilteredTopic.

Parameters

expressionParameters A reference to a sequence of strings that will be used to store the parameters used in the SQL expression.

Returns

Return values are:

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

◆ GetFilterExpression()

string DDS.IContentFilteredTopic.GetFilterExpression ( )

This operation returns the filterExpression associated with the IContentFilteredTopic.

The return string is the SQL filter expression which was specified when the the IContentFilteredTopic was created. The result is a string which specifies the criteria used to select the data samples of interest. It is similar to the WHERE clause of an SQL expression.

Returns: The string that specifies the criteria to select the data samples of interest.

◆ SetExpressionParameters()

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

This operation changes the expression parameters associated with the IContentFilteredTopic.

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

This operation changes the expression parameters associated with the IContentFilteredTopic. The parameter expressionParameters is a sequence of strings with the parameters used in the SQL expression. The number of values in expressionParameters must be equal or greater than the highest referenced n token in the filterExpression (for example, if %1 and %8 are used as parameter in the filterExpression, the expressionParameters should at least contain n+1 = 9 values). This is the filter expression specified when the IContentFilteredTopic was created.

Parameters

expressionParameters A sequence of strings with the parameters used in the SQL expression. The number of values in expressionParameters must be equal or greater than the highest referenced n token in the subscriptionExpression.

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 IContentFilteredTopic 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 IContentFilteredTopic or one of the parameters is an illegal parameter.

Property Documentation

◆ RelatedTopic

ITopic DDS.IContentFilteredTopic.RelatedTopic

get

This property returns the ITopic associated with the IContentFilteredTopic.

That is, the ITopic specified when the IContentFilteredTopic was created. This ITopic is the base topic on which the filtering will be applied.

Definition at line 2529 of file DdsDcpsInterfaces.cs.

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

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

Public Member Functions