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DDS::ContentFilteredTopic Class Reference

<<interface>> Specialization of ::DDS::TopicDescription that allows for content-based subscriptions. More...

#include <managed_topic.h>

Inheritance diagram for DDS::ContentFilteredTopic:
DDS::ITopicDescription

Public Member Functions

System::String^ get_filter_expression ()
 Get the filter_expression.
 
void get_expression_parameters (StringSeq^ parameters)
 Get the expression_parameters.
 
void set_expression_parameters (StringSeq^ parameters)
 Set the expression_parameters.
 
void set_expression (System::String^ expression, StringSeq^ parameters)
 Set the filter_expression and expression_parameters.
 
void append_to_expression_parameter (System::Int32 index, System::String^ val)
 <<extension>> Appends a string term to the specified parameter string.
 
void remove_from_expression_parameter (System::Int32 index, System::String^ val)
 <<extension>> Removes a string term from the specified parameter string.
 
Topicget_related_topic ()
 Get the related_topic.
 
- Public Member Functions inherited from DDS::ITopicDescription
System::String^ get_type_name ()
 Get the associated type_name.
 
System::String^ get_name ()
 Get the name used to create this ::DDS::TopicDescription .
 
DomainParticipantget_participant ()
 Get the DDS::DomainParticipant to which the ::DDS::TopicDescription belongs.
 

Static Public Member Functions

static ContentFilteredTopicnarrow (ITopicDescription^ topic_description)
 Narrow the given ::DDS::TopicDescription pointer to a DDS::ContentFilteredTopic pointer.
 

Detailed Description

<<interface>> Specialization of ::DDS::TopicDescription that allows for content-based subscriptions.

It describes a more sophisticated subscription that indicates a DDS::DataReader does not want to necessarily see all values of each instance published under the DDS::Topic. Rather, it wants to see only the values whose contents satisfy certain criteria. This class therefore can be used to request content-based subscriptions.

The selection of the content is done using the filter_expression with parameters expression_parameters.

  • The filter_expression attribute is a string that specifies the criteria to select the data samples of interest. It is similar to the WHERE part of an SQL clause.
  • The expression_parameters attribute is a sequence of strings that give values to the 'parameters' (i.e. "%n" tokens) in the filter_expression. The number of supplied parameters must fit with the requested values in the filter_expression (i.e. the number of n tokens).

Queries and Filters Syntax describes the syntax of filter_expression and expression_parameters.

Member Function Documentation

static ContentFilteredTopic ^ DDS::ContentFilteredTopic::narrow ( ITopicDescription topic_description)
static

Narrow the given ::DDS::TopicDescription pointer to a DDS::ContentFilteredTopic pointer.

Returns
DDS::ContentFilteredTopic if this ::DDS::TopicDescription is a DDS::ContentFilteredTopic. Otherwise, return NULL.
System::String ^ DDS::ContentFilteredTopic::get_filter_expression ( )

Get the filter_expression.

Return the filter_expression associated with the DDS::ContentFilteredTopic. filter_expression is either specified on the last successful call to DDS::ContentFilteredTopic::set_expression or, if that method is never called, the expression specified when the DDS::ContentFilteredTopic was created.

Returns
the filter_expression.
void DDS::ContentFilteredTopic::get_expression_parameters ( StringSeq parameters)

Get the expression_parameters.

Return the expression_parameters associated with the DDS::ContentFilteredTopic. expression_parameters is either specified on the last successful call to DDS::ContentFilteredTopic::set_expression_parameters, DDS::ContentFilteredTopic::set_expression or, if that method is never called, the parameters specified when the DDS::ContentFilteredTopic was created.

Parameters
parameters<<inout>> the filter expression parameters. Cannot be NULL.
Exceptions
Oneof the Standard Return Codes
See Also
DDS::DomainParticipant::create_contentfilteredtopic
DDS::ContentFilteredTopic::set_expression_parameters
void DDS::ContentFilteredTopic::set_expression_parameters ( StringSeq parameters)

Set the expression_parameters.

Change the expression_parameters associated with the DDS::ContentFilteredTopic.

Parameters
parameters<<in>> the filter expression parameters Cannot be NULL.Length of sequence cannot be greater than 100.
Exceptions
Oneof the Standard Return Codes
void DDS::ContentFilteredTopic::set_expression ( System::String^  expression,
StringSeq parameters 
)

Set the filter_expression and expression_parameters.

Changes the filter_expression and expression_parameters associated with the DDS::ContentFilteredTopic.

Parameters
expression<<in>> the filter expression. Cannot be NULL.
parameters<<in>> the filter expression parameters Cannot be NULL.Length of sequence cannot be greater than 100.
Returns
One of the Standard Return Codes.
void DDS::ContentFilteredTopic::append_to_expression_parameter ( System::Int32  index,
System::String^  val 
)

<<extension>> Appends a string term to the specified parameter string.

Appends the input string to the end of the specified parameter string, separated by a comma. If the original parameter string is enclosed in quotation marks (''), the resultant string will also be enclosed in quotation marks.

This method can be used in expression parameters associated with MATCH operators in order to add a pattern to the match pattern list. For example, if the filter expression parameter value is:

'IBM'

Then append_to_expression_parameter(0, "MSFT") would generate the new value:

'IBM,MSFT'

Parameters
index<<in>> The index of the parameter string to be modified. The first index is index 0. When using the DDS::DomainParticipant::STRINGMATCHFILTER_NAME filter, index must be 0.
val<<in>> The string term to be appended to the parameter string.
Exceptions
Oneof the Standard Return Codes
void DDS::ContentFilteredTopic::remove_from_expression_parameter ( System::Int32  index,
System::String^  val 
)

<<extension>> Removes a string term from the specified parameter string.

Removes the input string from the specified parameter string. To be found and removed, the input string must exist as a complete term, bounded by comma separators or the strong boundary. If the original parameter string is enclosed in quotation marks (''), the resultant string will also be enclosed in quotation marks. If the removed term was the last entry in the string, the result will be a string of empty quotation marks.

This method can be used in expression parameters associated with MATCH operators in order to remove a pattern from the match pattern list. For example, if the filter expression paremeter value is:

'IBM,MSFT'

Then remove_from_expression_parameter(0, "IBM") would generate the expression:

'MSFT'

Parameters
index<<in>> The index of the parameter string to be modified. The first index is index 0. When using the DDS::DomainParticipant::STRINGMATCHFILTER_NAME filter, index must be 0.
val<<in>> The string term to be removed from the parameter string.
Exceptions
Oneof the Standard Return Codes
Topic ^ DDS::ContentFilteredTopic::get_related_topic ( )

Get the related_topic.

Return the DDS::Topic specified when the DDS::ContentFilteredTopic was created.

Returns
The DDS::Topic assocated with the DDS::ContentFilteredTopic.

RTI Connext .Net APIs Version 5.2.0 Copyright © Sun Jun 21 2015 Real-Time Innovations, Inc