Wiki source code of SCCharts Development

Version 20.1 by ssm on 2016/04/22 14:40
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ssm 7.1 1 {{layout}}
2 {{layout-section ac:type="single"}}
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ssm 5.1 4 This is a light-weight tutorial for developing additions for SCCharts in KIELER. It will use Eclipse, EMF, and Xtend and therefore, finishing the corresponding tutorials could prove useful. However, they are not a strict requirement for this tutorial.
ssm 1.1 5
ssm 12.1 6
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8 {{toc/}}
9
ssm 1.1 10 = Preliminaries =
11
12 There's a few things to do before we dive into the tutorial itself. For example, to do Eclipse programming, you will have to get your hands on an Eclipse installation first. Read through the following sections to get ready for the tutorial tasks.
13
14 == Required Software ==
15
16 As you're going to develop for KIELER SCCharts we recommend to use the semantic Oomph setup as described in [[doc:KIELER.Getting Eclipse]] (Oomph Setup). However, you could also install all componentes by yourself. Please consult the other tutorials if you want to do that. You would need to install the Modeling Tools and the Xtext SDK.
ssm 7.1 17 {{/layout-cell}}
18 {{/layout-section}}
ssm 1.1 19
ssm 8.1 20 {{layout-section ac:type="three_equal"}}
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ssm 11.1 22
23
ssm 7.1 24 Additionally, install the** EcoreViz** from the **Ecore Model Visualization** category from the **OpenKieler** update site: [[http:~~/~~/rtsys.informatik.uni-kiel.de/~~~~kieler/updatesite/nightly-openkieler/>>url:http://rtsys.informatik.uni-kiel.de/~~kieler/updatesite/nightly-openkieler/||rel="nofollow" shape="rect"]]. For this, choose //Install New Software...// in the //Help// tab.
ssm 8.1 25
26 Due to the ongoing migration you have to install a workaround for EcoreViz to function. You have to install the KLighD diagram view directly from [[http:~~/~~/rtsys.informatik.uni-kiel.de/~~~~kieler/updatesite/release_pragmatics_2016-02/>>url:http://rtsys.informatik.uni-kiel.de/~~kieler/updatesite/release_pragmatics_2016-02/||shape="rect"]]. Select the features
27
28 * KIELER Lightweight Diagrams - Developer Resources and
29 * KIELER Lightweight Diagrams Generic Diagram View.
30
31 (This step should be obsolete in the near future.)
ssm 7.1 32 {{/layout-cell}}
ssm 1.1 33
ssm 7.1 34 {{layout-cell}}
ssm 11.1 35
36
ssm 7.1 37 [[image:attach:InstallEcoreViz.png]]
ssm 12.1 38
39
ssm 7.1 40 {{/layout-cell}}
ssm 8.1 41
42 {{layout-cell}}
ssm 11.1 43
44
ssm 8.1 45 [[image:attach:InstallKLighDFeatures.png]]
46 {{/layout-cell}}
ssm 7.1 47 {{/layout-section}}
48
49 {{layout-section ac:type="single"}}
50 {{layout-cell}}
ssm 1.1 51 == Recommended Tutorials ==
52
53 We recommend that you have completed the following tutorials before diving into this one (or at least sweep over them). However, this is not a strict requirement.
54
55 1. [[doc:Eclipse Plug-ins and Extension Points]]
56 1. [[doc:Eclipse Modeling Framework (EMF)]]
57 11. This tutorial needs the turingmachine.ecore and the controller you've implemented in the EMF tutorial. If you did not complete the EMF tutorial, you may download a working turing machine here... (in the future).
58 1. (((
59 (% class="with-breadcrumbs" %)
60 [[Xtend 2 - Model Transformations>>url:http://rtsys.informatik.uni-kiel.de/confluence/display/TUT/Xtend+2+-+Model+Transformations||shape="rect"]]
61 )))
62
63 == Helpful Tutorials ==
64
65 When developing within the KIELER semantics team, you will most likely be confronted with Xtext and [[doc:KIELER.Lightweight Diagrams (KLighD)]]. The following tutorials may be helpful but not required for this tutorial.
66
67 1. [[doc:Xtext 2 - Creating a Grammar from Scratch]]
68 1. [[doc:Lightweight Diagrams (KLighD)]]
69
70 == Finding Documentation ==
71
ssm 5.1 72 You can find additional documentation to the aforementioned topics in the corresponding tutorials. If you get stuck with a particular topic, please consult that tutorial. For SCCharts, you should read the SCCharts confluence page in our wiki: [[doc:KIELER.SCCharts]]
ssm 1.1 73
74 As usual, documentation often gets obsolete or wrong if not maintained regularly, so please, if you find missing, misleading, or outdated information, please let us know.
75
76 Additionally, the following list will give a short overview over the most important publications:
77
78 * (% style="color: rgb(0,0,0);" %)**Main paper:**
79 Reinhard von Hanxleden and Björn Duderstadt and Christian Motika and Steven Smyth and Michael Mendler and Joaquín Aguado and Stephen Mercer and Owen O’Brien. SCCharts: Sequentially Constructive Statecharts for Safety-Critical Applications. In (% class="cmti-10" %)Proc. ACM SIGPLAN Conference on Programming Language Design(%%) (% class="cmti-10" %)and Implementation (PLDI’14)(%%), Edinburgh, UK, June 2014. ACM. (%%)[[pdf>>url:http://rtsys.informatik.uni-kiel.de/~~biblio/downloads/papers/pldi14.pdf||shape="rect"]](% style="color: rgb(0,0,0);" %), (%%)[[talk>>url:http://rtsys.informatik.uni-kiel.de/~~biblio/downloads/talks/pldi14-talk.pdf||shape="rect"]](% style="color: rgb(0,0,0);" %), (%%)[[bib>>url:http://rtsys.informatik.uni-kiel.de/~~biblio/cgi-bin/bibcgi.cgi?key=vonHanxledenDM+14||shape="rect"]]
80 * **SLIC Compilation:**
81 (% style="color: rgb(0,0,0);" %)Christian Motika and Steven Smyth and Reinhard von Hanxleden. Compiling SCCharts—A Case-Study on Interactive Model-Based Compilation. In (% class="cmti-10" %)Proceedings of(%%) (% class="cmti-10" %)the 6th International Symposium on Leveraging Applications of Formal(%%) (% class="cmti-10" %)Methods, Verification and Validation (ISoLA 2014)(%%), volume 8802 of (% class="cmti-10" %)LNCS(%%), page 443–462, Corfu, Greece, October 2014. The (%%)[[original publication>>url:http://dx.doi.org/10.1007/978-3-662-45234-9||shape="rect"]](% style="color: rgb(0,0,0);" %) is available at (%%)[[http:~~/~~/link.springer.com>>url:http://link.springer.com/||shape="rect"]](% style="color: rgb(0,0,0);" %). (%%)[[pdf>>url:http://rtsys.informatik.uni-kiel.de/~~biblio/downloads/papers/isola14.pdf||shape="rect"]](% style="color: rgb(0,0,0);" %), (%%)[[bib>>url:http://rtsys.informatik.uni-kiel.de/~~biblio/cgi-bin/bibcgi.cgi?key=MotikaSvH14||shape="rect"]]
82 * **Theoretical Foundations:**
83 (% style="color: rgb(0,0,0);" %)Reinhard von Hanxleden and Michael Mendler and Joaquín Aguado and Björn Duderstadt and Insa Fuhrmann and Christian Motika and Stephen Mercer and Owen O’Brien and Partha Roop. Sequentially Constructive Concurrency—A Conservative Extension of the Synchronous Model of Computation. (% class="cmti-10" %)ACM Transactions on Embedded Computing(%%) (% class="cmti-10" %)Systems, Special Issue on Applications of Concurrency to System Design(%%), 13(4s):144:1–144:26, July 2014. (%%)[[pdf>>url:http://rtsys.informatik.uni-kiel.de/~~biblio/downloads/papers/tecs14.pdf||shape="rect"]](% style="color: rgb(0,0,0);" %), (%%)[[bib>>url:http://rtsys.informatik.uni-kiel.de/~~biblio/cgi-bin/bibcgi.cgi?key=vonHanxledenMA+14||shape="rect"]]
84 * **Overview and High-Level Transformations in Detail:**
85 (% style="color: rgb(0,0,0);" %)Reinhard von Hanxleden and Björn Duderstadt and Christian Motika and Steven Smyth and Michael Mendler and Joaquín Aguado and Stephen Mercer and Owen O’Brien. SCCharts: Sequentially Constructive Statecharts for Safety-Critical Applications. Technical Report 1311, Christian-Albrechts-Universität zu Kiel, Department of Computer Science, December 2013. ISSN 2192-6247. (%%)[[pdf>>url:http://rtsys.informatik.uni-kiel.de/~~biblio/downloads/papers/report-1311.pdf||shape="rect"]](% style="color: rgb(0,0,0);" %), (%%)[[bib>>url:http://rtsys.informatik.uni-kiel.de/~~biblio/cgi-bin/bibcgi.cgi?key=vonHanxledenDM+13b||shape="rect"]]
ssm 13.1 86
87
ssm 9.1 88 {{/layout-cell}}
89 {{/layout-section}}
ssm 1.1 90
ssm 9.1 91 {{layout-section ac:type="two_right_sidebar"}}
92 {{layout-cell}}
ssm 1.1 93 = The SCCharts Metamodel =
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ssm 9.1 95 Navigate to the {{code language="none"}}models{{/code}} folder of the plugin {{code language="none"}}de.cau.cs.kieler.sccharts{{/code}}. Here, open the {{code language="none"}}sccharts.ecore{{/code}} and right-click on the {{code language="none"}}sccharts.ecore{{/code}} file and select //Visualize Ecore Model//. Since you also installed **EcoreViz** from the OpenKieler Suite, you should now see a graphical representation of the SCCharts metamodel. Every SCChart will be a model of this metamodel.
ssm 1.1 96
ssm 14.1 97 To see all class information check //Attributes/Literals// in the Diagram Options on the right.
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ssm 15.1 99 EcoreViz gives you an overview over the selected Ecore diagram. However, Ecore model definitions may depend on other Ecore definitions that are not displayed in the diagram. You can open new diagrams for these Ecore files as described before or use the Ecore tree editor to inspect all classes.
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ssm 1.1 101 Try to understand most parts of the metamodel. You don't have to understand every detail but you should get the idea.
102
103 ==== Model Task ====
104
ssm 9.1 105 1. Answer the following questions
106 11. How do you describe a superstate in the model?
ssm 16.1 107 11. Outline the relationship between states, regions, transitions, and valued objects.\\
108 11. Name the class of the root element of an SCChart.
ssm 9.1 109 11. What is a valued object?
110 11. How do you get the type of an interface variable?
111 11. What other metamodels are needed for the SCCharts metamodel and write down which one is needed for what?
112 1. Write down (on paper, text editor, etc) how the following SCChart models look like
113 11. Open the wiki page that explains the [[doc:KIELER.Textual SCCharts Language SCT]].
114 11. Search the //SCChart, Initial State, State, Transition and Immediate Transition //example and ...
ssm 5.1 115 111. write down (on paper or text editor, etc) how the model of that SCChart looks like.
116 111. The user now marks C as final. What has to be changed in the model? What semantic problem do you see?
ssm 9.1 117 11. Now, navigate to the //Super State: Strong Abort Transition //example. Write down (on paper) how the model of that SCCharts looks like.
ssm 5.1 118 11. And finally a more sophisticated model: Write down the model of ABO (from [[doc:KIELER.Examples]]).
ssm 4.1 119
ssm 9.1 120
121
122 {{info title="KLighD Screenshots"}}
ssm 17.1 123 By the way: You can //right-click// on the Diagram View surface and select //Save as image...// to create a screenshot!
ssm 9.1 124 {{/info}}
125 {{/layout-cell}}
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127 {{layout-cell}}
128 [[image:attach:sccharts_metamodel.png]]
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ssm 15.1 130 [[image:attach:sccharts_metamodel_treeEditor.png]]
ssm 9.1 131
132 [[image:attach:KLighDSaveAsImage.png]]
133 {{/layout-cell}}
134 {{/layout-section}}
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136 {{layout-section ac:type="single"}}
137 {{layout-cell}}
ssm 4.1 138 = Creating SCCharts Models Programmatically =
139
140 == Creating a Test Project ==
141
142 We need a project for testing. Do the following:
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ssm 18.1 144 1. If you used the standard KIELER Oomph installation setup, create a new Working Set named Tutorial in the Package Explorer. Then...
ssm 4.1 145 1. Create a new empty //Plug-In Project//.
146 1. Add the project that contains the sccharts metamodel as a dependency of your new project through the //Plugin Manifest Editor//.
147 1. Create a simple Java class that implements a main method. Hint: In a new Java class, simply type main and hit Ctrl+Space. Eclipse content assist will create the method for you.
148
149 == Creating a Model ==
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ssm 18.1 151 To create a model programmatically you cannot directly use the Java classes generated for the model. Instead, the main package contains interfaces for all of your model object classes. The {{code language="none"}}impl{{/code}} package contains the actual implementation and the {{code language="none"}}util{{/code}} package contains some helper classes. Do not instantiate objects directly by manually calling {{code language="none"}}new{{/code}}. EMF generates a Factory to create new objects. The factory itself uses the singleton pattern to get access to it:
ssm 4.1 152
153 {{code language="java"}}
154 SCChartsFactory sccFactory = SCChartsFactory.eINSTANCE;
ssm 19.1 155 State state = sccFactory.createState();
156 Transition transition = sccFactory.createTransition();
ssm 4.1 157 {{/code}}
158
159 Important: The SCCharts grammar is build on top of several other grammars. Therefore, not all language objects can be found in the SCCharts factory. For example, all expression elements are part of the KExpressions grammar and hence, have their own factory. If you need other factories, don't forget to add the corresponding plugin to your plugin dependency list.
160
161 {{code language="java"}}
162 KExpressionsFactory kFactory = KExpressionsFactory.eINSTANCE;
ssm 18.1 163 BoolValue boolValue = kFactory.createBoolValue();
ssm 4.1 164 {{/code}}
165
166 For all simple attributes, there are getter and setter methods:
167
168 {{code language="java"}}
ssm 19.1 169 state.setId("Init");
ssm 4.1 170 boolValue.setValue(true);
171 {{/code}}
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173 Simple references (multiplicity of 1) also have getters and setters:
174
175 {{code language="java"}}
176 transition.setTrigger(boolValue);
177 {{/code}}
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179 List references (multiplicity of > 1) have only a list getter, which is used to manipulate the list:
180
181 {{code language="java"}}
ssm 18.1 182 state.getOutgoingTransitions().add(transition);
ssm 4.1 183 {{/code}}
184
ssm 18.1 185 {{info title="Plugin Dependencies"}}
186 You may have noticed that is was not necessary to add a dependency for the kexpressions classes. The SCCharts plugin reexports the dependencies of the other EMF metamodels. Look at the plugin.xml in the SCCharts plugin in the dependency tab for more information.
187 {{/info}}
188
ssm 4.1 189 == Saving a Model ==
190
191 EMF uses the [[Eclipse Resource concept>>url:http://help.eclipse.org/juno/topic/org.eclipse.platform.doc.isv/guide/resInt.htm?cp=2_0_10||rel="nofollow" shape="rect" class="external-link"]] to save models to files and load models from files. It can use different //Resource Factories// that determine how exactly models are serialized. We will use the [[XMIResourceFactoryImpl>>url:http://download.eclipse.org/modeling/emf/emf/javadoc/2.8.0/org/eclipse/emf/ecore/xmi/impl/XMIResourceFactoryImpl.html||rel="nofollow" shape="rect" class="external-link"]] to save our models to XML files:
192
193 1. (((
ssm 19.1 194 Add a dependency to the {{code language="none"}}com.google.inject, org.eclipse.core.resources, {{/code}}and{{code language="none"}} de.cau.cs.kieler.sccharts.text{{/code}} plug-ins.
195
196 {{info title="Additional Dependencies"}}
197 Don't worry. You will be experienced enough to add mandatory dependencies quickly in the future. However, for now just add the dependencies to proceed with the tutorial.
198 {{/info}}
199 )))
200 1. (((
ssm 4.1 201 Use something like the following code to save the model from above:
202
203 {{code language="java"}}
204 // Create a resource set.
205 ResourceSet resourceSet = new ResourceSetImpl();
206
ssm 19.1 207 // Register the resource factory -- only needed for stand-alone!
208 SctStandaloneSetup.doSetup();
209
210  
ssm 4.1 211 // Get the URI of the model file.
212 URI fileURI = URI.createFileURI(new File("myABO.sct").getAbsolutePath());
213
214 // Create a resource for this file.
215 Resource resource = resourceSet.createResource(fileURI);
216
217 // Add the model objects to the contents.
218 resource.getContents().add(myModel);
219
220 // Save the contents of the resource to the file system.
221 try
222 {
223 resource.save(Collections.EMPTY_MAP); // the map can pass special saving options to the operation
224 } catch (IOException e) {
225 /* error handling */
226 }
227 {{/code}}
ssm 20.1 228
229 {{info title="File Extensions"}}
230 File extensions are important! They define the parser/serializer that EMF uses. Always use the file extension that is defined for a particular model.
231 {{/info}}
ssm 4.1 232 )))
ssm 19.1 233 {{/layout-cell}}
234 {{/layout-section}}
ssm 4.1 235
ssm 19.1 236 {{layout-section ac:type="two_right_sidebar"}}
237 {{layout-cell}}
ssm 4.1 238 ==== Model Creation Task ====
239
ssm 19.1 240 You are now equipped with the fundamentals you need to create models programmatically. Let's try it:
ssm 4.1 241
ssm 19.1 242 1. The code fragments listed above do not suffice to create a grammatically correct model. Try to generate a model that corresponds with the serialized model listed on the right side.
243 11. Run the {{code language="none"}}main(){{/code}} method by right-clicking its class and selecting (% style="line-height: 1.42857;" %)//Run as//(%%) -> (% style="line-height: 1.42857;" %)//Java Application//(%%). Note that this runs your {{code language="none"}}main(){{/code}} method as a simple Java program, not a complete Eclipse application. EMF models can be used in any simple Java context, not just in Eclipse applications.
244 11. Execute the main method.
ssm 20.1 245 11. (((
246 Inspect your SCT file. (Press F5 to refresh your file view.)
247
248 {{note title="Kext Warning"}}
249 It is possible that kext generates a Null Pointer Exception when you save your model this way. This is a known issue. We're working on it. Just ignore it for now.
250 {{/note}}
251 )))
ssm 19.1 252 1. Now, create a new Java class and proceed as before to generate a model of ABO in the {{code language="none"}}main(){{/code}} method.
ssm 4.1 253 1. Start your SCChart Editor Eclipse instance and load your SCT file. KLighD should now be able to visualize your ABO correctly.
ssm 20.1 254 11. For this, open tab //Run// and select// Run Configurations...//
255 11. Create a new //Eclipse Application// and name it appropriately.
256 11. As product select {{code language="none"}}de.cau.cs.kieler.core.product.product{{/code}}.
257 11. Click //Run// (or //Debug// if you opened// Debug Configuration...//)
258 11. Create a new project and add you generated model.
ssm 19.1 259
260
ssm 18.1 261 {{/layout-cell}}
ssm 19.1 262
263 {{layout-cell}}
264 {{code language="java" title="Root.sct"}}
265 scchart Root {
266 initial state Init
267 --> Init with true;
268 }
269 {{/code}}
ssm 20.1 270
271 [[image:attach:RunConfiguration.png]]
ssm 19.1 272 {{/layout-cell}}
ssm 18.1 273 {{/layout-section}}
ssm 4.1 274
ssm 19.1 275 {{layout-section ac:type="two_right_sidebar"}}
ssm 18.1 276 {{layout-cell}}
ssm 20.1 277 = Model-to-Model Transformation with KiCo =
278
279 You can use the [[Kieler Compiler>>url:http://rtsys.informatik.uni-kiel.de/confluence/display/KIELER/Kieler+Compiler||shape="rect"]] (KiCo) to handle all the model input/output tasks and concentrate on the actual transformation. If you executed the **Model Creation Task correctly**, you should now have a complete running SCT Editor instance that looks like the one on the right. You should see the //KIELER Compiler Selection// n the lower right part of the working space. Here you can select specific transformations that will be applied to the actual model. Simply select a transformation to test it.
280
281 == Creating a new Transformation ==
282
283 Now, you're going to write your own transformation with **Xtend** *drumroll*, a programming language that looks very similar to Java, but which adds some very convenient features. Xtend code compiles to Java and and was developed using Xtext. In fact, once you gain experience working with Xtend you will probably appreciate the power of Xtext even more. Xtend is particularly useful to browse & modify EMF models. You get the point... we like it. :)
284
ssm 18.1 285
ssm 20.1 286
287 Transformation Creation Task
288
289 1. Therefore, create a new project within your tutorial working set as before.
290 1. Add plugin dependencies to {{code language="none"}}de.cau.cs.kieler.kico{{/code}} and {{code language="none"}}de.cau.cs.kieler.sccharts{{/code}}.
291 1. Create a new //Xtend class// in you package and name it "DoubleStates" and use {{code language="none"}}AbstractProductionTransformation{{/code}} as superclass.
292 1. Here, you can automatically add the missing Xtend files by using the quickfix //Add Xtend lib to class path. //Alternatively you can simply add {{code language="none"}}com.google.guava{{/code}}, {{code language="none"}}org.eclipse.xtext.xbase.lib{{/code}}, {{code language="none"}}org.eclipse.xtend.lib{{/code}}, and {{code language="none"}}org.eclipse.xtend.lib.macro{{/code}} to you plugin dependencies.
293 1. Click on //Add unimplemented methods//.
294 1. (((
295 Now, you should have a class similar to the following one.
296
297 {{code language="java"}}
298 package tutorial.transformation
299
300 import de.cau.cs.kieler.kico.transformation.AbstractProductionTransformation
301
302 class DoubleStates extends AbstractProductionTransformation {
303
304 override getProducedFeatureId() {
305 throw new UnsupportedOperationException("TODO: auto-generated method stub")
306 }
307
308 override getId() {
309 throw new UnsupportedOperationException("TODO: auto-generated method stub")
310 }
311
312 }
313 {{/code}}
314 )))
315 1. (((
316 As you can see, it is mandatory to add an id for the transformation and another id of the feature that this transformation produces. Name your transformation **tutorial.doubleStates **and the id of feature you want to produce is **sccharts.doubleStates**.
317
318 {{info title="Programming Guidelines"}}
319 You should really think about some constants here. You can also look at the sccharts transformation and features constants in the sccharts plugin.
320 {{/info}}
321 )))
322 1. KiCo must know about the new feature and also about your new transformation. 
323 11. Add a new Xtend class with Feature as superclass. Add all unimplemented methods. Also set sccharts.doubleStates as Id.
324 11. Go to the Extension tab inside your plugin configuration. 
325 111. Add a new Extension Point de.cau.cs.kieler.kico.feature. Create a new featureClass and point it to your new feature class.
326 111. Also add a new Extension Point de.cau.cs.kieler.kico.transformation. Create a new productionTransformationClass and point it to your transformation class.
327 111. Finally, you have to link your transformation to the SCT Editor. Add the Extension point de.cau.cs.kieler.kico.ui.transformation. Create an editor link and fill in the following values:
328 1111. editor: de.cau.cs.kieler.sccharts.text.sct.Sct
329 1111. features: sccharts.doubleStates
330 1111. label: Tutorial Compilation
331 1111. priority: 101
332 1111. preferred: (leave it blank)
333 11. If you start your KIELER instance now, you should get a new compilation chain which has only one transformation: yours, which doesn't do anything.
334 1. If you want to rename your feature in the Compiler Selection (without changing its Id), override the getName method and return a new name. Rename your feature appropriately.
335
336
ssm 18.1 337 {{/layout-cell}}
ssm 19.1 338
339 {{layout-cell}}
ssm 20.1 340 [[image:attach:KielerSCTEditor.png]]
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388 [[image:attach:KielerSCTEditorOwnTransformation.png]]
ssm 19.1 389 {{/layout-cell}}
ssm 18.1 390 {{/layout-section}}
391
392 {{layout-section ac:type="single"}}
393 {{layout-cell}}
ssm 4.1 394 = Transforming SCCharts =
395
396 Transformations from one model to another may be performed within the same metamodel or from metamodel to a different metamodel. Both methods are used in KIELER and in principle they do not really differ in implementation. Nevertheless, if working within the same metamodel you should keep in mind that you're potentially changing the actual model instead of changing another instance (after copying). Both is possible. Just make sure that you know what you're doing.
397
398 Now, you're going to transform the normalized form of HandleA from ABO to an SCG. The Sequentially Constructive Graph is a control-flow graph which can be seen as another representation of the same program. The SCG of the normalized version of ABO's HandleA is depicted on the right.
399
400 |(((
401 {{code}}
402 scchart ABO_norm_HandleA {
403 input output bool A;
404 input output bool B;
405 output bool O1;
406 output bool O2;
407 region HandleA:
408 initial state WaitA
409 --> _S immediate with A
410 --> _Pause immediate;
411 final state DoneA;
412 state _S
413 --> _S2 immediate with / B = true;
414 state _S2
415 --> DoneA immediate with / O1 = true;
416 state _Pause
417 --> _Depth;
418 state _Depth
419 --> _S immediate with A
420 --> _Pause immediate;
421 }
422 {{/code}}
423 )))|(((
424 [[image:attach:abo_norm_HandleA.png]]
425 )))|(% colspan="1" %)(% colspan="1" %)
426 (((
427 [[image:attach:abo_scg_HandleA.png]]
428 )))
429
430 The next figure depicts the direct mapping from normalized SCCharts to their corresponding SCG.
431
432 [[image:attach:sccharts-scg.png]]
433
434 Inspect the metamodel of the SCGs in plugin de.cau.cs.kieler.scg. SCGs are used for analyses and optimization and include a lot of additional elements. However, for this tutorial it should be sufficient to look at the SCGraph class, its nodes attribute, the important node classes and the controlflow class. Important nodes for this SCG are entry, exit, assignment, conditional,
435
436 ==== Transformation Task ====
437
438 Write a transformation that transforms your normalized version of ABO's HandleA into its corresponding SCG.
439
440 1. (((
441 **Writing a Model Transformation**
442
443 This time we want you to integrate your transformation into your SCCharts Editor instance. Therefore,...
444 (% style="color: rgb(51,51,51);line-height: 1.66667;" %)\\
445
446 1. Add a new package 
447
448 {{code language="none"}}
449 <project>.transformations
450 {{/code}} to your project.
451 1. Add an //Xtend Class// to the new package.
452 1. If you notice that your new class is marked with an error marker because of a missing dependency of the new plug-in project to 
453
454 {{code language="none"}}
455 org.eclipse.xtext.xbase.lib, 
456 {{/code}}you can hover over the error with your mouse and have Eclipse add all libraries required by Xtend to your project.
457 1.
458
459 Define an entry method for the transformation that takes an SCChart program instance as an argument and returns an SCG {{code language="none"}}Program{{/code}}. You can use the following (incomplete) method as a starting point:
460
461 (((
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464
465
466 |(((
467 (% class="container" title="Hint: double-click to select code" %)
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471 {{code language="none"}}
472 /**
473 {{/code}}
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477 (((
478 {{code language="none"}}
479  
480 {{/code}}
481
482 {{code language="none"}}
483 * Transforms a given SCCharts program into an SCG.
484 {{/code}}
485 )))
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489 {{code language="none"}}
490  
491 {{/code}}
492
493 {{code language="none"}}
494 *
495 {{/code}}
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500 {{code language="none"}}
501 */
502 {{/code}}
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507 {{code language="none"}}
508 def SCGraph transform(State rootState) {
509 {{/code}}
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514 {{code language="none"}}
515     
516 {{/code}}
517
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519 // Create the SCG
520 {{/code}}
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525 {{code language="none"}}
526     
527 {{/code}}
528
529 {{code language="none"}}
530 val scg = SCGraphFactory::eINSTANCE.createSCGraph()
531 {{/code}}
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536 {{code language="none"}}
537   
538 {{/code}}
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543 {{code language="none"}}
544     
545 {{/code}}
546
547 {{code language="none"}}
548 // TODO: Your transformation code
549 {{/code}}
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554 {{code language="none"}}
555   
556 {{/code}}
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561 {{code language="none"}}
562     
563 {{/code}}
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566 // Return the transformed program
567 {{/code}}
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572 {{code language="none"}}
573     scg
574 {{/code}}
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579 {{code language="none"}}
580 }
581 {{/code}}
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592 (((
593 There's a few points to note here:
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ssm 1.1 597 \\
ssm 4.1 598
599 1.
600 1*. Lines in Xtend code don't have to and with a semicolon.
601 1*. We have been explicit about the method's return type, but we could have easily omitted it, letting Xtend infer the return type.
602 1*. The keyword 
603
604 {{code language="none"}}
605 val
606 {{/code}} declares a constant, while 
607
608 {{code language="none"}}
609 var
610 {{/code}} declares a variable. Try to make do with constants where possible.
611 1*. The methods you call should be declared as 
612
613 {{code language="none"}}
614 def private
615 {{/code}} since they are implementation details and shouldn't be called by other classes.
616 1*. You may be tempted to add a few global variables that hold things like a global input variable or a pointer to the current state. While you could to that, 
617
618 {{code language="none"}}
619 def create 
620 {{/code}}methods might offer a better alternative...
621 \\
622 1. Replace the TODO with an transformation code that takes an extended BF program and transforms it into an semantically equivalent BF program that only uses standard BF instructions. 
623 HINT: Some of the extended BF commands can only be expressed by standard operations if you can write to other cells. Therefore you are allowed to perform side effects on the tape.
624 1. Open the //Plug-In Manifest Editor// and switch to the Runtime tab. Add the package containing your transformation to the list of exported packages. (You may have to check the //Show non-Java packages// option in the //Exported Packages// dialog to see the package.)
625 \\
626 )))
627 1. **Verify your generated SCG**. If you added your transformation correctly, the SCG should be displayed automatically as soon as selected. If your SCG looks like the SCG depicted earlier, then everything is fine.
628 1. Check your SCG semantically. Is there anything you could improve/optimize? 
629 11. Write a second transformation (just as before) and add it to the transformation chain right after the transformation you already added.
630 11. Optimize the given SCG and compare the result with the previous one.
631 11. Make sure that the two SCGs are still semantically identical.
632
633 Congratulations! You finished the SCCharts Development Tutorial. Ask your supervisor for further instructions!
634
635
ssm 7.1 636 {{/layout-cell}}
637 {{/layout-section}}
638 {{/layout}}

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