see [TUTORIAL_ADD_MIDDLEWARE.md](https://git.rwth-aachen.de/monticore/EmbeddedMontiArc/generators/EMAM2Middleware/blob/master/TUTORIAL_ADD_MIDDLEWARE.md)
## Usage
### CLI
Maven generates the jar `embedded-montiarc-math-middleware-generator-{Version}-jar-with-dependencies.jar`
and the cli is located in `de.monticore.lang.monticar.generator.middleware.DistributedTargetGeneratorCli`.
CLI Options:
* -m/--models-dir: full path to directory with EMAM models
* -r/--root-model: fully qualified name of the root model
* -o/--output-dir: full path to output directory for generated files
* -g/--generators: identifiers for the generators that should be used
### Defining the connection between a component and the middleware
The connection between middleware and the component is defined as tags on Ports in .tag files.
#### ROS:
### Example with ROS Middleware:
Tags of the type RosConnection can either be simple tags(see Example 3) or define a topic(http://wiki.ros.org/Topics) with name, type and optional msgField(http://wiki.ros.org/msg , 2.)
Look at GenerationTest::testMiddlewareGenerator. The component is defined in src/test/resources/tests/a/AddComp.emam (TODO: link) and the tags for the connection to ros are defined in src/test/resources/tests/a/Add.tag (TODO: link)
#### Use-case 1: Creating 1 executable
Look at [GenerationTest::testMiddlewareGenerator](https://git.rwth-aachen.de/monticore/EmbeddedMontiArc/generators/EMAM2Middleware/blob/master/src/test/java/de/monticore/lang/monticar/generator/middleware/GenerationTest.java). The component is defined in [src/test/resources/tests/a/AddComp.emam](https://git.rwth-aachen.de/monticore/EmbeddedMontiArc/generators/EMAM2Middleware/blob/master/src/test/resources/tests/a/AddComp.emam) and the tags for the connection to ros are defined in [src/test/resources/tests/a/Add.tag](https://git.rwth-aachen.de/monticore/EmbeddedMontiArc/generators/EMAM2Middleware/blob/master/src/test/resources/tests/a/Add.tag)
### Use case 2: Creating multiple executables for distributed systems
Look at GenerationTest::testDistributedTargetGenerator. The component is defined in src/test/resources/dist/DistComp.emam (TODO: link) and the tags for the connection to ros are defined in src/test/resources/dist/SimpleDist.tag (TODO: link)
#### Use-case 2: Creating multiple executables for distributed systems
Look at [GenerationTest::testDistributedTargetGenerator](https://git.rwth-aachen.de/monticore/EmbeddedMontiArc/generators/EMAM2Middleware/blob/master/src/test/java/de/monticore/lang/monticar/generator/middleware/GenerationTest.java). The component is defined in [src/test/resources/dist/DistComp.emam](https://git.rwth-aachen.de/monticore/EmbeddedMontiArc/generators/EMAM2Middleware/blob/master/src/test/resources/tests/dist/DistComp.emam) and the tags for the connection to ros are defined in [src/test/resources/tests/dist/SimpleDist.tag](https://git.rwth-aachen.de/monticore/EmbeddedMontiArc/generators/EMAM2Middleware/blob/master/src/test/resources/tests/dist/SimpleDist.tag)
To save the additional middleware information in the Symbol Table, the field `PortSymbol::middlewareSymbol` is used.
Add a new class for your middleware that extends [MiddlewareSymbol](https://git.rwth-aachen.de/monticore/EmbeddedMontiArc/languages/EmbeddedMontiArc/blob/master/src/main/java/de/monticore/lang/embeddedmontiarc/tagging/middleware/MiddlewareSymbol.java)(Example:[RosConnectionSymbol](https://git.rwth-aachen.de/monticore/EmbeddedMontiArc/languages/EmbeddedMontiArc/blob/master/src/main/java/de/monticore/lang/embeddedmontiarc/tagging/middleware/ros/RosConnectionSymbol.java)).
To keep the model clean of middleware specific code, the [Tagging](https://git.rwth-aachen.de/monticore/EmbeddedMontiArc/languages/Tagging) mechanism is used. Generate/Create a new Tagging Schema (Example: [RosToEmamTagSchema](https://git.rwth-aachen.de/monticore/EmbeddedMontiArc/languages/EmbeddedMontiArc/blob/master/src/main/java/de/monticore/lang/embeddedmontiarc/tagging/middleware/ros/RosToEmamTagSchema.java)) and SymbolCreator(Example: [RosConnectionSymbolCreator](https://git.rwth-aachen.de/monticore/EmbeddedMontiArc/languages/EmbeddedMontiArc/blob/master/src/main/java/de/monticore/lang/embeddedmontiarc/tagging/middleware/ros/RosConnectionSymbolCreator.java))
for your new MiddlewareSymbol. Make sure to load all your tags before starting generation(Example: [TagHelper::resolveTags](https://git.rwth-aachen.de/monticore/EmbeddedMontiArc/generators/EMAM2RosCpp/blob/master/src/main/java/de/monticore/lang/monticar/generator/roscpp/helper/TagHelper.java))
## Generator
The new middleware generator needs to the following methods
*`setGenerationTargetPath(String path)`: Sets the directory the generated files are written to.
*`boolean willAccept(ExpandedComponentInstanceSymbol componentInstanceSymbol)`: Signals the DistributedTargetGenerator if the middleware generator will generate useful files for the given component.
* Example: If a Component without RosConnections is passed to the ROS generator, it will reject it.
*`List<File> generate(ExpandedComponentInstanceSymbol componentInstanceSymbol, TaggingResolver taggingResolver)`: Generates all files(Adapter + CMake) for the given Component.
These 3 methods are combined in the Interface [GeneratorImpl](https://git.rwth-aachen.de/monticore/EmbeddedMontiArc/generators/EMAM2Middleware/blob/master/src/main/java/de/monticore/lang/monticar/generator/middleware/impls/GeneratorImpl.java).
To avoid a cyclic dependency between the new middleware generator and EMAM2Middleware, it is advised to write a small wrapper in EMAM2Middleware instead of implementing the Interface directly. See [RosCppGenImpl](https://git.rwth-aachen.de/monticore/EmbeddedMontiArc/generators/EMAM2Middleware/blob/master/src/main/java/de/monticore/lang/monticar/generator/middleware/impls/RosCppGenImpl.java) for an example.
## Generated C++ Adapter
The generated C++ Adapter needs to stick to the following conventions:
All examples are given for the middleware ROS and a component named `AddComp` from the package `tests.a`.
***Class name:** Java convention, file name = class name
* Example: `class RosAdapter_tests_a_addComp` in `RosAdapter_tests_a_addComp.h`
***Interfaces:** The generated coordinator for the Component contains the interface `IAdapter_{Component.fullQualifiedName}.h` which the new Adapter needs to implement.
* Example:
```
#include "IAdapter_tests_a_addComp.h"
...
class RosAdapter_tests_a_addComp: public IAdapter_tests_a_addComp{...};
```
***init method:** The Interface contains the Method ``init({Component.fullQualifiedName}* comp)`` that sets the shared instance of the Component and starts the middleware in this thread.
* Example:
```
#include "tests_a_addComp.h"
#include <ros/ros.h>
...
tests_a_addComp* component;
...
void init(tests_a_addComp* comp){
this->component = comp; //saves the shared instance for later use
...
ros::spin(); //starts ROS in this thread and blocks it!
}
```
***tick method:** The Interface contains the Method `tick()` that the coordinator executes in an defined interval(e.g. every 100ms). The middleware needs to publish all outgoing connections in this method. Do not call `component.execute()` here, as the coordinator aleady does that!
* Example:
```
void tick(){
//publish the values of the out1 Port of the Component to ROS
std_msgs::Float64 tmpMsg;
tmpMsg.data = component->out1;
_echoPublisher.publish(tmpMsg);
}
```
***Build script:** A CMake build script needs to be generated.
1. The project needs to have the same name as the Adapter.
2. The middleware libraries need to be a) located, b) linked, and c) included
3. A target for a static library with the same name as the Adapter needs to be a) defined and b) exported
4. The C++ code for the a) Component and b) Coordinator must be linked/included
5. All includes and the header file for the adapter need to be accessible from the super project
