How the workbench is able to help you in your metamodelling tasks

Nowadays a textual editor is not just an editable document. Many informations have been provided to the user in order to get improved editing performances. It is quite common to find textual editor with coloring syntax, auto-completion and outline. These three items working together usually makes a good textual editor. That is the reason why the Kermeta platform provides such an editor. Below, you can find the global view of the Kermeta editor.

Figure 2.1. The Kermeta Textual Editor

To develop faster and faster, some nice helpful tools now are usual. One of them is the auto-completion. According to a context, a list of item will be proposed. Using the arrows key and the carriage return key, you can select quickly and easily the item you want. The important thing is that, the list of item is calculated in order to only propose some relevant items. The figure below shows the auto-completion for "stdio" which is a special class in Kermeta (as System for Java). The typed point makes the system think that you want to call a method on "stdio". Then all the callable methods are proposed and you can choose one of them.

	Note
	The usual <ctrl>+<space> keyboard shortcut is used to access the code completion

Figure 2.2. Auto-Completion in the Kermeta Textual Editor

The outline is a structural view of your program. Code is not visible in this view, but the structure (packages, classes, attributes, methods and constraints) are visible in a tree hierarchy. Usually the outline position is on the top right side of the Eclipse's window. You can get advantages of the outline, when your program reaches a big size and when it is difficult to get a good visibility on the program's structure. Browsing the outline is much more faster than browsing the file. Moreover, clicking on an item (packages, classes, attributes or methods) brings you to that item in the file.

	Note
	The Flatten inheritance also display the features of the Object class as all the Kermeta classes inherit from it.

	Warning
	The "Show imported types" feature works on a per file basis and then it only shows the features declared using the require statement in this file and NOT all the files in your project. This option is really useful when you work with kermeta aspects since it display the elements in your faile and the elements imported by aspect.

In addition, the elements are colored in order to help to identify where and how an element is defined.

Figure 2.3. The outline in Kermeta Text Editor

	Tip
	A double click will open the editor in order to show you the selected element. This feature works only if the element to display is in a kmt file.

	Tip
	If you have activated the KermetaDoc view, it will show the documentation associated to the selected element.

	Note
	In version 1.2.2, the constrains don't have a color differentiation.

The textual editor is used to display extra pieces of information than simple text. In the figure below, a parsing error is reporting because of the semicolon which is not allowed in the language. The nice is thing is that in the Eclipse's problems view, just by double clicking on an error opens the erroneous file and make the cursor focusing on the correct line.

In addition, a list of all current errors is available in the general "Problems view".

Figure 2.4. Error reporting

Kermeta is meant an executable language and provides a debugger. So, the textual editor is used to interact with the debugger.

Like in a Java style, some breakpoints can be added to the program by right clicking on the grey line at the left of the editor (as in the figure below). The breakpoint will be added in front of the selected line. Afterwards, when running the debugger, the program will halt at every breakpoint it goes through. At this moment, you will be able to have a look at the variables' value and run step by step or step into some methods.

See Chapter 5, Debugging for more details on the debugger features.

Figure 2.5. Debugging Information in the Kermeta Text Editor

You can customize your text editor by selecting Window from the Eclipse main menu and then Preferences. The image below shows the page configurator.

Figure 2.6. TextEditor preferences

For those who already know how to run Java applications, this is a similar approach but for Kermeta files.

You'll need to create a new run configuration from the "Run/Run..." menu.

Figure 3.1. Run menu

	Caution
	The run menu is available only with some perspectives. If you don't see the run menu, switch to the Kermeta perspective.

In the dialog, you selects the file, the main class and the main operation that must be run.

Search buttons will help you to find these elements in your files.

	Caution
	The search button may not work properly if your file contains errors.

Figure 3.2. Kermeta run configuration - main tab

Two optional annotations in your Kermeta code allow you to save time while creating run configurations. The @mainClass and @mainOperation are used to fill field when creating a new configuration.

Ex:

@mainClass "fsm::Main"
@mainOperation "mainloadFSM"

Then, once you have your configuration, you can run it by all the means provided by Eclipse. Ie. "Run Last Launched", " Run History", ... available in the menus or in the toolbars.

	Tip
	A shortcut allows you to quickly start a Kermeta run configuration. It is available in the popup menu of *.kmt files. The " Run As/Kermeta App " button runs an existing configuration and the " Run As/Run... " button opens the configuration dialog.

Figure 3.3. Run shortcut to run configuration on the kmt files

The operation arguments field allow you to pass some strings as parameters of the operation you are launching.

In this sample screenshot, the FSM take a string as teh path to the file that will be loaded and simulated.

In addtion to this simple scenario, in the common Tab of the Kermeta run configuration, you can:

	Tip
	If you specify the kermeta project u=in the run configuration and if this project is an eclipse plugin, then the interpreter will automatically take this plugin and all its dependencies into account in tha classpath.

You can run Kermeta interpreter from the command line. For this you need to run the java class org.kermeta.interpreter.api.RunCommandLine which is available in fr.irisa.triskell.kermeta.interpreter plugin. The RunCommandLine class allows to pass the name of: the Kermeta source file, and optionally the name of the class and the operation to run.

	Note
	The package org.kermeta.interpreter.api provides different facades in order to run a Kermeta program with the interpreter from a java program. You can either have a look to the document Deploying Kermeta code manual or you may also have a look into class RunCommandLine to see how it was implemented.

The interpreter command line is available in two main forms : as a set of eclipse plugin (it is available with all kermeta version deployed in Eclipse, or as a standalone jar (see Kermeta download page for the various distributions).

The standalone bundle is available in two version : all in one jar (typically kermeta_standalone_full_1.3.0.jar), or only kermeta in the main jar (typically kermeta_standalone_no_thirdparty_in_main_jar.1.3.0.zip. In this second version, the thirdparty jar aren't included.

Depending wether you use the standalone jars or the jar embedded in eclipse, the process will be more or less simple. The simpliest is to use the standalone version because you don't need to deal with the classpath.

java -jar kermeta_standalone.jar  -U ecore_mdk/add_observer.kmt -C pattern::AddObserver -O main 
         input_models/needs_observer.ecore output_models/ Compteur Afficheur 

java -jar kermeta_standalone.jar  -P -U ../ModelEngineeringCourse/transfo/add_observer.kmt -C pattern_macros::Main -O main 
        -K lib/framework.km ../models/needs_observer.ecore Compteur Afficheur 

3.2.2. About the URI map

When you run a kermeta program outside of Eclipse, the uri of type platform:// are not resolved since this is the role of Eclipse to resolve them. So, when running outiside of Eclipse, you need to help this resolution.

The resolution can be done using a map, whenever it find the key, it will replace it with the associated value. Like that you can transform platform:/plugin/ into a physical location in your disk.

With RunCommandLine.java, this is the option -U which allow to specify a file that contains the mapping.

This uri map file uses the syntax of java properties files.

Example of uri.map file which maps some platform:// urls into file:// urls

#Typical uri.map file
"platform:/plugin/"   "file:/C:/eclipse3.4/eclipse/workspace_head/"
"platform:/resource/" "file:/C:/eclipse3.4/eclipse/workspace_head/"
"kconf:/loader/"      "file:/C:/eclipse3.4/eclipse/workspace_head/org.kermeta.io.loader/instances/" 

This special uri is used by kermeta to retrieve the folder instances in the plugin org.kermeta.io.loader. Kermeta intepreter cannot work correctly without it. Another easy way (not detailed here) would be to retrieve one of the standalone versions and run it from eclipse.

	Tip
	With this map mechanism, you can also translate the platform uris into jar protocol. This protocol allows to search within a jar. for example, jar:file:/my.jar!/src/kermeta/framework.km opens the file my.jar and pick the file named framework.km into the subfolder src/kermeta in the jar.

3.2.3. Run the eclipse version of the interpreter in eclipse

In this section we focus on calling the interpreter embedded in an eclipse installation.

	Note
	This is quite an advanced use case recommanded only for people who understand how eclipse files are organized and can manually create a classpath to retreive the various jar in eclipse installation.

From eclipse, you create a Java application LaunchConfiguration that will run the interpreter with your Kermeta file.

Figure 3.4. Java run configuration main tab

Be careful, you must select "Include external jars when searching for a main class".

Figure 3.5. Java run configuration arguments

The output level of interpreter traces can be set using a log4j configuration file. The concrete file to use is set by the java property "kermeta.log4j.configurationfile.name". A sample of log4j configuration file is located in the fr.irisa.triskell.kermeta.model plugin.

Exemple add the following in the VM arguments box: -Dkermeta.log4j.configurationfile.name= "../../plugins/fr.irisa.triskell.kermeta.model_1.3.0/kermeta_log4j_configuration.xml"

The classpath must be carefully set using the jar of Kermeta, the jar of Ecore and of emf.

Figure 3.6. Java run configuration classpath (using the interpreter jars in the texteditor)

	Tip
	This RunCommandLine class or one of its sibling can also be used by any of your java programs.For more information please see the Javadoc reference of RunCommandLine.

	Warning
	This method need to know precisely which jar you use. If you update any of the required plugins (kermeta, emf, ecore , ...) the directory containing the jar will change because eclipse use the version number as part of the directory name. You'll have to manually change to ant file in order to reflect the update.

The Kermeta compiler consists on a transformation from a kmt file to an Ecore file (step 1), finally the generation a plugin with the Java by using the EMF facilities (step 2). The resulting Java may be used both in Eclipse Application or in Java Application (standalone) and is fully compatible with EMF. A listing of dependencies is available below. The compiling process generates a set of files: *.km, *.traceability, *.ecore, *.simk, *.genmodel. A configuration file may be added: *.compiler.properties (more info. below). The 2nd step may be replayed by a right-click on the generated Ecore file.

A debugger offers users the possibility to interpret Kermeta's programs step by step, or stopping programs at one moment to check the the programs' state. Above you can see the global view of the editor.

Figure 5.1. The Debugger global view

During programs execution, you may want to know variables' values. For that purpose, you can use the watch view which displays all the variables accessible in the current context and their values. Moreover you can browse those variables to have a deeper look inside variables.

Figure 5.2. The Watch View

A frame is a context environment for a call method. That means that for each method call, you have access to its context that is to say the variables values. Obviously, it is strongly related to the watch view. Clicking on one frame modifies the watch view. The frame view is also nice to follow the execution. For instance, in the figure above, we know that the run method has called the step method which has called the fire method.

Figure 5.3. The Frame View

When debugging, you surely want to know which line of code is executed. That is the reason why the Kermeta text editor is displayed with the outline. The current line of code is colored in green as in the following figure. This green line is moving to the next instruction depending your action.

Figure 5.4. The Editor View

There are three kind of actions you can execute:

	Note
	A nice feature is that you can add or remove breakpoints to your Kermeta file during debugging.

For many of those transformations, the wizard will propose you to store the traceability informations.

This is a special metamodel that stores a link between the sources elements and the target element so you can reuse it later. For example, it will help the debugger to retrieve the correct line in the text version of the source file even if you are running the km version.

This metamodel is very generic and can be used for any model.

The Kermeta Graphical Editor is a view of the Kermeta model as a class diagram. It is generated with the tool "Topcased". The file containing the presentation informations is a *.kmdi. The *.kmdi is associated with a *.km file. The *.kmdi and *.km files must be in the same folder.

Figure 8.1. Class diagram Kermeta Model editor - overview

We can open it, simply select and right-click "Open with / Kermeta class diagram"

Figure 8.2. Opening of a Kermeta class diagram

In order to create a Kermeta class diagram you have 2 ways.

Figure 8.3. Creating of a Kermeta class diagram from scratch - 1rst step

Figure 8.4. Creating of a Kermeta class diagram from scratch - 2nd step

Figure 8.5. Creating of a Kermeta class diagram from an existing Kermeta model - 1rst step

Figure 8.6. Creating of a Kermeta class diagram from an existing Kermeta model - 2nd step

[TODO check with the platform tip and tricks page which eclipse shortcut correctly work with Kermeta editor]