EXAMPLES
Ownership
1) Description
The ownership example is used to illustrate the concept of Shared Ownership, controlled
through QoS, in DDS.
2) Design
It consists of 4 units :
- CheckStatus : provides return status checking
- DDSEntityManager : implements a class providing operations to setup DCPS
entities(creation, deletion)
- Publisher application implements the 2 publishers sharing the same topic.
- Subscriber implements the subscriber.
3) Scenario
Two StockQuote Publishers of different ownership strengths publish topics with the same
keyfields. The subscriber will receive the topics from the publisher with higher strength.
In this example :
- a publisher "pub1" having an ownership strength set to 5 sends periodically 20
StockQuotes at a period of 200ms.
- after 2 seconds a second publisher "pub2" with a higher strength (10) sends 5
StockQuotes at a period of 200ms. When receiving a topic, the subscriber will display the :
- the key field (always "MSFT")
- the price field
- the publisher name ("pub1" or "pub2")
The publisher will receive :
- first StockQuotes from "pub1" (during the first 2 seconds)
- then from "pub2"
- then from "pub1" again when "pub2" stops.
Running of examples in Standalone Mode
Running the examples in a Posix environment
Environment Setup
Let's call OpenSplice_install_dir the OpenSplice installation directory.
The OpenSpliceDDS environment variables must be set in order for the examples to build/run correctly.
To do this, open a terminal and source the "OpenSplice_install_dir/release.com" script supplied with the distribution.
C and C++ Executables
Building the examples is described on the Summary page
Two executables and a library are generated in the standalone directory when the example is built:
For C++
- sacpp_ownership_pub
- sacpp_ownership_sub
- libsacpp_ownership_types.so
For C
- sac_ownership_pub
- sac_ownership_sub
- libsac_ownership_types.so
Java executables
Building the examples is described on the Summary page
Two jars are generated in the standalone directory when the example is built:
- saj_ownership_app.jar
- saj_ownership.jar
Running the example
Ensure that the environment for OpenSpliceDDS is set up correctly as described above for each new terminal used. If running the C or C++ examples ensure that
. is added to the LD_LIBRARY_PATH.
It is recommended that you run the subscriber and publisher in separate terminals to avoid mixing the output
Running in single process (heap memory) configuration : the application starts OpenSpliceDDS middleware
- OpenSpliceDDS is deployed in this mode by default.
- The OpenSplice daemon should not be started manually. Instead the OpenSpliceDDS middleware and optional services are implicitly started by the single process applications as required
- Open 2 or more terminals. Set up the environment and go to directory standalone as described above
Running in multiple process shared memory configuration
To enable deployment in this mode, an OpenSpliceDDS configuration file must be selected that has shared memory support e.g. one of the ospl_shmem xml configuration files found in the OpenSplice_install_dir/etc/config directory.
- Open 2 or more terminals. In each terminal:
- Setup the environment and go to directory standalone as described above
- Set the required configuration file e.g. OSPL_URI=file://$OSPL_HOME/etc/config/ospl_shmem_ddsi.xml
- Start the OpenSplice daemon. You can do this by typing ospl start
Starting the subscriber and publisher
- In the first terminal start the subscriber by running either
- sac_ownership_sub for C OR
- sacpp_ownership_sub for C++ OR
- java-classpath $OSPL_HOME/jar/dcpssaj.jar:classes OwnershipDataSubscriber for Java
- In a second terminal start the publisher by running either
- sac_ownership_pub pub1 5 40 1 for C OR
- sacpp_ownership_pub pub1 5 40 1 for C++ OR
- java -classpath $OSPL_HOME/jar/dcpssaj.jar:classes OwnershipDataPublisher pub1 5 40 1 for Java
In another terminal start the publisher by running either
- sac_ownership_pub pub2 10 5 0 for C OR
- sacpp_ownership_pub pub2 10 5 0 for C++ OR
- java -classpath $OSPL_HOME/jar/dcpssaj.jar:classes OwnershipDataPublisher pub2 10 5 0 for Java
Publisher usage, e.g.:
sac_ownership_pub [publisher_name] [ownership_strength] [nb_iterations] [stop_subscriber_flag]
publisher_name
ownership_strength
nb_iterations : number of sending message iterations
stop_subscriber_flag : indicates if the publisher has to sent a message to tell the subscriber to stop
Running C/C++/C#/Java examples on Windows
Environment Setup
Let's call OpenSplice_install_dir the OpenSplice installation directory.
The OpenSpliceDDS environment variables must be set in order for the examples to run correctly.
To do this open an OpenSpliceDDS Command Prompt which will set up the environment variables for OpenSpliceDDS automatically. The OpenSpliceDDS Command Prompt can be selected from the start menu. Alternatively, open a windows Command Prompt and execute the "OpenSplice_install_dir\release.bat" batch script supplied with the distribution.
C/C++/C# Executables
Building the examples is described on the Summary page
Two executables are generated in the standalone directory when the example is built:
For C
- sac_ownership_sub.exe
- sac_ownership_pub.exe
For C++
- sacpp_ownership_sub.exe
- sacpp_ownership_pub.exe
Java Executables
Building the examples is described on the Summary page
The subscriber and publisher classes are generated in the standalone directory when the example is built:
- OwnershipDataPublisher.class
- OwnershipDataSubscriber.class
Running the C/C++/C#/Java Examples
Ensure that the environment for OpenSpliceDDS is set up correctly as described above for each new command prompt used.
The following steps describe how to run the examples:
Running in single process (heap memory) configuration : the application starts OpenSpliceDDS middleware
- OpenSpliceDDS is deployed in this mode by default.
- The OpenSplice daemon should not be started manually. Instead the OpenSpliceDDS middleware and optional services are implicitly started by the single process applications as required
- Open 2 or more OpenSpliceDDS Command Prompts and go to directory standalone as described above
Running in multiple process shared memory configuration
To enable deployment in this mode, an OpenSpliceDDS configuration file must be selected that has shared memory support e.g. one of the ospl_shmem xml configuration files found in the OpenSplice_install_dir\etc\config directory.
- Open 2 or more OpenSpliceDDS Command Prompts. In each window:
- Go to directory standalone as described above
- Set the required configuration file e.g. set OSPL_URI="file://%OSPL_HOME%\etc\config\ospl_shmem_ddsi.xml"
- Start the OpenSplice daemon. You can do this by typing ospl start
Starting the subscriber and publisher
- In the first terminal start the subscriber by running either
- sac_ownership_sub for C OR
- sacpp_ownership_sub for C++ OR
- java -classpath "%OSPL_HOME%\jar\dcpssaj.jar";classes OwnershipDataSubscriber for Java
- In a second terminal start the publisher by running either
- sac_ownership_pub pub1 5 40 1 for C OR
- sacpp_ownership_pub pub1 5 40 1 for C++ OR
- java -classpath "%OSPL_HOME%\jar\dcpssaj.jar";classes OwnershipDataPublisher pub1 5 40 1 for Java
In another terminal start the publisher by running either
- sac_ownership_pub pub2 10 5 0 for C OR
- sacpp_ownership_pub pub2 10 5 0 for C++ OR
- java -classpath "%OSPL_HOME%\jar\dcpssaj.jar";classes OwnershipDataPublisher pub2 10 5 0 for Java
Publisher usage, e.g.:
sac_ownership_pub [publisher_name] [ownership_strength] [nb_iterations] [stop_subscriber_flag]
publisher_name
ownership_strength
nb_iterations : number of sending message iterations
stop_subscriber_flag : indicates if the publisher has to sent a message to tell the subscriber to stop