EXAMPLES
Lifecycle
1) Description
The Lifecycle example is used to illustrate the different lifecycle states of the sample
and the instance.
- The SampleState applies to an individual sample and is either READ or NOT_READ,
depending on whether the sample has been accessed from this reader before.
- The ViewState applies to an individual instance (possibly containing of 1 or
more samples)
and is either NEW or NOT_NEW, depending on whether a sample belonging to the same
instance
has been accessed from this reader before.
- The InstanceState applies to an individual instance (possibly containing of 1 or
more samples) and is either
- ALIVE
- NOT_ALIVE_DISPOSED
- NOT_ALIVE_NO_WRITERS
depending on whether the
Lifecycle publisher has still registered the instance, has disposed it or has
unregistered it.
The autodispose_unregistered_instances flag of the Lifecycle publisher determines whether an
invocation of unregister_instance on this publisher will cause the instance to become disposed.
2) Design
It consists of 4 units:
- CheckStatus: provides return status checking
- DDSEntitiesManager: implements a class providing operations to setup DCPS
entities
(creation, deletion)
- LifecyclePublisher: implements the publisher's main (uses DDSEntitiesManager)
- LifecycleSubscriber: implements the subscriber's main (uses DDSEntitiesManager)
3) Scenario
The Publisher and the Subscriber processes communicate using the following topic:
struct Msg
{
long userID; // User ID
string message; // content;
string writerStates; // the different state of the writer
};
The writerStates field contains the different states of the writer :
- "SAMPLE_SENT -> INSTANCE_DISPOSED -> DATAWRITER_DELETED"
- "SAMPLE_SENT -> INSTANCE_UNREGISTERED -> DATAWRITER_DELETED"
- "SAMPLE_SENT -> DATAWRITER_DELETED"
usage : LifecycleDataPublisher [autodispose_flag] [writer_action]
. autodispose_flag = false | true
. writer_action = dispose | unregister | stoppub
The LifecyclePublisher : Depending on the user's choice as the second parameter passed on command line (dispose | unregister | stoppub),
it will either:
- Case 1 : second parameter passed on command line "dispose"
- publish the Msg Sample.
- Dispose the instance.
- Delete the DataWriter.
- Stop the Subscriber.
- Case 2 : second parameter passed on command line "unregister"
- publish the Msg Sample.
- Unregister the instance.
- Delete the DataWriter.
- Stop the Subscriber.
- Case 3 : second parameter passed on command line "stoppub"
- publish the Msg Sample.
- Delete the DataWriter.
- Stop the Subscriber.
For any of those actions, it will output on its console:
- "SAMPLE SENT"
- "INSTANCE DISPOSED"
- "INSTANCE UNREGISTERED"
- "DATAWRITER DELETED"
- "STOPPING SUBSCRIBER"
|
The LifecycleSubscriber :
- Reads the (same unique) Msg Topic Sample.
- Display the Sample's information:
- The 2 fields of Msg Topic : message and writerStates
- The States :
- The "sample_state", possible values are:
- "NOT_READ_SAMPLE_STATE"
- "READ_SAMPLE_STATE"
- The "view_state", possible values are:
- "NEW_VIEW_STATE"
- "NOT_NEW_VIEW_STATE"
- The "instance_state", possible values are
- "ALIVE_INSTANCE_STATE"
- "NOT_ALIVE_DISPOSED_INSTANCE_STATE"
- "NOT_ALIVE_NO_WRITERS"
|
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_lifecycle_pub
- sacpp_lifecycle_sub
- libsacpp_lifecycle_types.so
For C
- sac_lifecycle_pub
- sac_lifecycle_sub
- libsac_lifecycle_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_lifecycle_app.jar
- saj_lifecycle.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 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 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_lifecycle_sub for C OR
- sacpp_lifecycle_sub for C++ OR
- java -classpath $OSPL_HOME/jar/dcpssaj.jar:classes LifecycleDataSubscriber for Java
- In the second terminal start the publisher by running either
- sac_lifecycle_pub [autodispose_flag] [writer_action] for C OR
- sacpp_lifecycle_pub [autodispose_flag] [writer_action] for C++ OR
- java -classpath $OSPL_HOME/jar/dcpssaj.jar:classes LifecycleDataPublisher [autodispose_flag] [writer_action] for Java
usage : LifecycleDataPublisher [autodispose_flag] [writer_action]
Where
. autodispose_flag = false | true
. writer_action = dispose | unregister | stoppub
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_lifecycle_sub.exe
- sac_lifecycle_pub.exe
For C++
- sacpp_lifecycle_sub.exe
- sacpp_lifecycle_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:
- LifecycleDataPublisher.class
- LifecycleDataSubscriber.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 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 OpenSpliceDDS Command Prompts. In each window:
- Go to directory standalone as described above
- Set the required configuraton 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_lifecycle_sub for C OR
- sacpp_lifecycle_sub for C++ OR
- start java -classpath "%OSPL_HOME%\jar\dcpssaj.jar";classes LifecycleDataSubscriber for Java
- In the second terminal start the publisher by running either
- sac_lifecycle_pub [autodispose_flag] [writer_action] for C OR
- sacpp_lifecycle_pub [autodispose_flag] [writer_action] for C++ OR
- java -classpath "%OSPL_HOME%\jar\dcpssaj.jar";classes LifecycleDataPublisher [autodispose_flag] [writer_action] for Java
usage : LifecycleDataPublisher [autodispose_flag] [writer_action]
Where
. autodispose_flag = false | true
. writer_action = dispose | unregister | stoppub