DDS::ContentFilteredTopic Class Reference
[Topics]

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

#include <managed_topic.h>

Inheritance diagram for DDS::ContentFilteredTopic:

DDS::ITopicDescription

List of all members.

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 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.
Topic^ get_related_topic ()
 Get the related_topic.
virtual System::String^ get_type_name ()
 Get the associated type_name.
virtual System::String^ get_name ()
 Get the name used to create this DDS::TopicDescription .
virtual DomainParticipant^ get_participant ()
 Get the DDS::DomainParticipant to which the DDS::TopicDescription belongs.

Static Public Member Functions

static ContentFilteredTopic^ narrow (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.

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

Note on Content-Based Filtering and Sparse Value Types

If you are a user of the Dynamic Data API, you may define sparse value types; that is, types for which every data sample need not include a value for every field defined in the type. (See DDS::TCKind::TK_SPARSE and DDS::TypeCodeFactory::create_sparse_tc.) In order for a filter expression on a field to be well defined, that field must be present in the data sample. That means that you will only be able to perform a content-based filter on fields that are marked as DDS::TypeCode::KEY_MEMBER or DDS::TypeCode::NONKEY_REQUIRED_MEMBER.

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.

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 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:
One of 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:
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:
One of 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:
One of 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.

virtual System::String ^ DDS::ContentFilteredTopic::get_type_name (  )  [virtual]

Get the associated type_name.

The type name defines a locally unique type for the publication or the subscription.

The type_name corresponds to a unique string used to register a type via the FooTypeSupport::register_type method.

Thus, the type_name implies an association with a corresponding DDS::TypeSupport and this DDS::TopicDescription.

Returns:
the type name. The returned type name is valid until the DDS::TopicDescription is deleted.
Postcondition:
The result is non-NULL.
See also:
DDS::TypeSupport, FooTypeSupport

Implements DDS::ITopicDescription.

virtual System::String ^ DDS::ContentFilteredTopic::get_name (  )  [virtual]

Get the name used to create this DDS::TopicDescription .

Returns:
the name used to create this DDS::TopicDescription. The returned topic name is valid until the DDS::TopicDescription is deleted.
Postcondition:
The result is non-NULL.

Implements DDS::ITopicDescription.

virtual DomainParticipant ^ DDS::ContentFilteredTopic::get_participant (  )  [virtual]

Get the DDS::DomainParticipant to which the DDS::TopicDescription belongs.

Returns:
The DDS::DomainParticipant to which the DDS::TopicDescription belongs.
Postcondition:
The result is non-NULL.

Implements DDS::ITopicDescription.

RTI Data Distribution Service .Net APIs Version 4.5e Copyright © 23 Oct 2011 Real-Time Innovations, Inc