[1895] Implement textual export of StateUsage and StateDefinition

Signed-off-by: Arthur Daussy <arthur.daussy@obeo.fr>
Bug: #1895

Author: adaussy

CHANGELOG.adoc

@@ -22,6 +22,8 @@ SysON now uses its own indexing logic instead of the default one provided by Sir
 This allows to limit the size of the indices, and ensure information stored in the indices are useful to perform cross-project search.
 You can find more information on how to setup Elasticsearch, how elements are mapped to index documents, and how to query them in the documentation.
 - https://github.com/eclipse-syson/syson/issues/1861[#1861] [publication] Split `SysONLibraryPublicationHandler` in two distinct classes so the publishing logic can be extended or re-used through the `ISysMLLibraryPublisher` API.
+- https://github.com/eclipse-syson/syson/issues/1895[#1895] [export] Implement textual export of `StateUsage` and `StateDefinition`.
+
 
 === New features
 

backend/application/syson-application/src/test/java/org/eclipse/syson/application/export/ImportExportTests.java

@@ -1335,6 +1335,64 @@ public void checkConnectionUsageWithBody() throws IOException {
                 .check();
     }
 
+    /**
+     * Test import/export on test file StateTest.sysml. The content of StateTest.sysml that have been copied below
+     * is under LGPL-3.0-only license. The LGPL-3.0-only license is accessible at the root of this repository, in the
+     * LICENSE-LGPL file.
+     *
+     * <p><b>NOTE:</b> The TransitionUsage has been remove from the original model for this test.</p>
+     *
+     * @see <a href=
+     * "https://github.com/Systems-Modeling/SysML-v2-Release/blob/master/sysml/src/examples/Simple%20Tests/StateTest.sysml">StateTest.sysml</a>
+     */
+    @Test
+    @DisplayName("GIVEN a model with StateUsage and StateDefinition, WHEN importing and exporting the model, THEN the states are properly exported")
+    public void checkStates() throws IOException {
+        var input = """
+                package StateTest {
+                    attribute def Sig {
+                        x;
+                    }
+                    attribute def Exit;
+                    part p;
+                    action act;
+                    state def S {
+                        do action A;
+                        entry ;
+                        state S1;
+                        state S2 {
+                            state S3;
+                        }
+                        exit act;
+                        state S3 {
+                            state S3a;
+                        }
+                    }
+                    state s0 {
+                        state s1 {
+                            state s2;
+                        }
+                        state s3 {
+                            state s4;
+                        }
+                    }
+                    state s parallel {
+                        state s1;
+                        state s2;
+                    }
+                    state s4 {
+                        do action a;
+                        action c;
+                    }
+                    state s5 :> s4 {
+                        do action b :>> c;
+                    }
+                }""";
+        this.checker.textToImport(input)
+                .expectedResult(input)
+                .check();
+    }
+
     @Test
     @DisplayName("GIVEN with conflicting names used in refence, WHEN importing and exporting the model, THEN the names used in the qualified name should be properly escaped.")
     public void checkNameConflictResolutionWithQn() throws IOException {

backend/metamodel/syson-sysml-metamodel/src/main/java/org/eclipse/syson/sysml/textual/SysMLElementSerializer.java

@@ -128,6 +128,8 @@
 import org.eclipse.syson.sysml.SelectExpression;
 import org.eclipse.syson.sysml.Specialization;
 import org.eclipse.syson.sysml.StakeholderMembership;
+import org.eclipse.syson.sysml.StateDefinition;
+import org.eclipse.syson.sysml.StateSubactionMembership;
 import org.eclipse.syson.sysml.StateUsage;
 import org.eclipse.syson.sysml.Subclassification;
 import org.eclipse.syson.sysml.SubjectMembership;
@@ -228,13 +230,24 @@ public String caseActionDefinition(ActionDefinition actionDef) {
     @Override
     public String caseActionUsage(ActionUsage actionUsage) {
         Appender builder = new Appender(this.lineSeparator, this.indentation);
-        this.appendOccurrenceUsagePrefix(builder, actionUsage);
-        builder.appendWithSpaceIfNeeded("action");
-        this.appendActionUsageDeclaration(builder, actionUsage);
+        if (!this.isEmptyActionAsStateSubAction(actionUsage)) {
+            // Normal rule "ActionUsage"
+            this.appendOccurrenceUsagePrefix(builder, actionUsage);
+            builder.appendWithSpaceIfNeeded("action");
+            this.appendActionUsageDeclaration(builder, actionUsage);
+
+        } // Rule "EmptyActionUsage" when store in StateSubactionMembership => Do nothing
+
         this.appendChildrenContent(builder, actionUsage, actionUsage.getOwnedMembership());
+
         return builder.toString();
     }
 
+    private boolean isEmptyActionAsStateSubAction(ActionUsage actionUsage) {
+        return actionUsage.getOwningMembership() instanceof StateSubactionMembership && actionUsage.getOwnedRelationship()
+                .isEmpty() && actionUsage.getDeclaredName() == null && actionUsage.getShortName() == null;
+    }
+
     @Override
     public String caseAnalysisCaseUsage(AnalysisCaseUsage analysisCaseUsage) {
         this.reportUnhandledType(analysisCaseUsage);
@@ -863,29 +876,21 @@ public String casePartUsage(PartUsage partUsage) {
     }
 
     @Override
-    public String casePerformActionUsage(PerformActionUsage perfomActionUsage) {
+    public String casePerformActionUsage(PerformActionUsage performActionUsage) {
 
         Appender builder = new Appender(this.lineSeparator, this.indentation);
+        if (!(performActionUsage.getOwningMembership() instanceof StateSubactionMembership)) {
+            // Rule simple "PerformActionUsage" from BehaviorUsageElement
+            this.appendOccurrenceUsagePrefix(builder, performActionUsage);
 
-        this.appendOccurrenceUsagePrefix(builder, perfomActionUsage);
+            builder.appendWithSpaceIfNeeded("perform");
+        } // Else do nothing using rule PerformActionUsageDeclaration
 
-        builder.appendWithSpaceIfNeeded("perform");
+        this.appendPerformActionUsageDeclaration(performActionUsage, builder);
 
-        Appender nameAppender = new Appender(this.lineSeparator, this.indentation);
-        this.appendNameWithShortName(nameAppender, perfomActionUsage);
-
-        if (nameAppender.isEmpty() && perfomActionUsage.getOwnedReferenceSubsetting() != null) {
-            // Use simple form : perfom <nameOfReferenceSubSetting>
-            this.appendOwnedReferenceSubsetting(builder, perfomActionUsage.getOwnedReferenceSubsetting());
-        } else {
-            // Use complete form
-            builder.appendWithSpaceIfNeeded("action");
-            this.appendUsageDeclaration(builder, perfomActionUsage);
-        }
+        this.appendValuePart(builder, performActionUsage);
 
-        this.appendValuePart(builder, perfomActionUsage);
-
-        this.appendChildrenContent(builder, perfomActionUsage, perfomActionUsage.getOwnedMembership());
+        this.appendChildrenContent(builder, performActionUsage, performActionUsage.getOwnedMembership());
 
         return builder.toString();
     }
@@ -1065,10 +1070,56 @@ public String caseStakeholderMembership(StakeholderMembership stakeholderMembers
         return builder.toString();
     }
 
+    @Override
+    public String caseStateDefinition(StateDefinition stateDefinition) {
+        Appender builder = this.newAppender();
+        this.appendDefinitionPrefix(builder, stateDefinition);
+        builder.appendSpaceIfNeeded().append(SysMLv2Keywords.STATE + " " + SysMLv2Keywords.DEF);
+        this.appendDefinitionDeclaration(builder, stateDefinition);
+
+        if (stateDefinition.isIsParallel()) {
+            builder.appendWithSpaceIfNeeded(SysMLv2Keywords.PARALLEL);
+        }
+
+        this.appendChildrenContent(builder, stateDefinition, stateDefinition.getOwnedMembership());
+        return builder.toString();
+    }
+
+    @Override
+    public String caseStateSubactionMembership(StateSubactionMembership stateSubactionMembership) {
+        Appender builder = this.newAppender();
+
+        this.appendMembershipPrefix(stateSubactionMembership, builder);
+
+        String stateKind = switch (stateSubactionMembership.getKind()) {
+            case DO -> SysMLv2Keywords.DO;
+            case ENTRY -> SysMLv2Keywords.ENTRY;
+            case EXIT -> SysMLv2Keywords.EXIT;
+        };
+
+        builder.appendWithSpaceIfNeeded(stateKind);
+
+        String content = stateSubactionMembership.getOwnedRelatedElement().stream()
+                .map(this::doSwitch).filter(Objects::nonNull).collect(joining(builder.getNewLine()));
+        builder.appendSpaceIfNeeded().append(content);
+
+        return builder.toString();
+    }
+
     @Override
     public String caseStateUsage(StateUsage stateUsage) {
-        this.reportUnhandledType(stateUsage);
-        return "";
+        Appender builder = this.newAppender();
+
+        this.appendOccurrenceUsagePrefix(builder, stateUsage);
+        builder.appendWithSpaceIfNeeded(SysMLv2Keywords.STATE);
+        this.appendActionUsageDeclaration(builder, stateUsage);
+
+        if (stateUsage.isIsParallel()) {
+            builder.appendWithSpaceIfNeeded(SysMLv2Keywords.PARALLEL);
+        }
+
+        this.appendChildrenContent(builder, stateUsage, stateUsage.getOwnedMembership());
+        return builder.toString();
     }
 
     @Override
@@ -2803,4 +2854,18 @@ private boolean useRequirementConstraintUsageShortHandNotation(ConstraintUsage c
                 && constraintUsage.getOwnedReferenceSubsetting() != null
                 && constraintUsage.getNestedMetadata().isEmpty();
     }
+
+    private void appendPerformActionUsageDeclaration(PerformActionUsage performActionUsage, Appender builder) {
+        Appender nameAppender = new Appender(this.lineSeparator, this.indentation);
+        this.appendNameWithShortName(nameAppender, performActionUsage);
+
+        if (nameAppender.isEmpty() && performActionUsage.getOwnedReferenceSubsetting() != null) {
+            // Use simple form : perfom <nameOfReferenceSubSetting>
+            this.appendOwnedReferenceSubsetting(builder, performActionUsage.getOwnedReferenceSubsetting());
+        } else {
+            // Use complete form
+            builder.appendWithSpaceIfNeeded("action");
+            this.appendUsageDeclaration(builder, performActionUsage);
+        }
+    }
 }

doc/content/modules/user-manual/pages/release-notes/2026.3.0.adoc

@@ -20,6 +20,8 @@ It's not recommended for production use.
 
 == Improvements
 
+* Implement the textual export for `StateUsage` and `StateDefinition`.
+
 == Technical details
 
 * For technical details on this {product} release (including breaking changes), please refer to https://github.com/eclipse-syson/syson/blob/main/CHANGELOG.adoc[changelog].