structurizr-dsl: Adds support for element!= expressions.

Author: simonbrowndotje

build.gradle

@@ -8,7 +8,7 @@ subprojects { proj ->
 
     description = 'Structurizr'
     group = 'com.structurizr'
-    version = '3.1.0'
+    version = '3.2.0'
 
     repositories {
         mavenCentral()

changelog.md

@@ -1,5 +1,9 @@
 # Changelog
 
+## 3.2.0 (unreleased)
+
+- structurizr-dsl: Adds support for `element!=` expressions.
+
 ## 3.1.0 (4th November 2024)
 
 - structurizr-client: Workspace archive file now includes the branch name in the filename.

structurizr-dsl/src/main/java/com/structurizr/dsl/ExpressionParser.java

@@ -18,21 +18,22 @@ static boolean isExpression(String token) {
         token = token.toLowerCase();
 
         return
+                token.startsWith(ELEMENT_EQUALS_EXPRESSION.toLowerCase()) ||
+                token.startsWith(ELEMENT_NOT_EQUALS_EXPRESSION.toLowerCase()) ||
                 token.startsWith(ELEMENT_TYPE_EQUALS_EXPRESSION.toLowerCase()) ||
-                        token.startsWith(ELEMENT_TAG_EQUALS_EXPRESSION.toLowerCase()) ||
-                        token.startsWith(ELEMENT_TAG_NOT_EQUALS_EXPRESSION.toLowerCase()) ||
-                        token.startsWith(ELEMENT_TECHNOLOGY_EQUALS_EXPRESSION.toLowerCase()) ||
-                        token.startsWith(ELEMENT_TECHNOLOGY_NOT_EQUALS_EXPRESSION.toLowerCase()) ||
-                        token.matches(ELEMENT_PROPERTY_EQUALS_EXPRESSION) ||
-                        token.startsWith(ELEMENT_PARENT_EQUALS_EXPRESSION.toLowerCase()) ||
-                        token.startsWith(RELATIONSHIP) || token.endsWith(RELATIONSHIP) || token.contains(RELATIONSHIP) ||
-                        token.startsWith(ELEMENT_EQUALS_EXPRESSION) ||
-                        token.startsWith(RELATIONSHIP_TAG_EQUALS_EXPRESSION.toLowerCase()) ||
-                        token.startsWith(RELATIONSHIP_TAG_NOT_EQUALS_EXPRESSION.toLowerCase()) ||
-                        token.matches(RELATIONSHIP_PROPERTY_EQUALS_EXPRESSION) ||
-                        token.startsWith(RELATIONSHIP_SOURCE_EQUALS_EXPRESSION.toLowerCase()) ||
-                        token.startsWith(RELATIONSHIP_DESTINATION_EQUALS_EXPRESSION.toLowerCase()) ||
-                        token.startsWith(RELATIONSHIP_EQUALS_EXPRESSION);
+                token.startsWith(ELEMENT_TAG_EQUALS_EXPRESSION.toLowerCase()) ||
+                token.startsWith(ELEMENT_TAG_NOT_EQUALS_EXPRESSION.toLowerCase()) ||
+                token.startsWith(ELEMENT_TECHNOLOGY_EQUALS_EXPRESSION.toLowerCase()) ||
+                token.startsWith(ELEMENT_TECHNOLOGY_NOT_EQUALS_EXPRESSION.toLowerCase()) ||
+                token.matches(ELEMENT_PROPERTY_EQUALS_EXPRESSION) ||
+                token.startsWith(ELEMENT_PARENT_EQUALS_EXPRESSION.toLowerCase()) ||
+                token.startsWith(RELATIONSHIP) || token.endsWith(RELATIONSHIP) || token.contains(RELATIONSHIP) ||
+                token.startsWith(RELATIONSHIP_TAG_EQUALS_EXPRESSION.toLowerCase()) ||
+                token.startsWith(RELATIONSHIP_TAG_NOT_EQUALS_EXPRESSION.toLowerCase()) ||
+                token.matches(RELATIONSHIP_PROPERTY_EQUALS_EXPRESSION) ||
+                token.startsWith(RELATIONSHIP_SOURCE_EQUALS_EXPRESSION.toLowerCase()) ||
+                token.startsWith(RELATIONSHIP_DESTINATION_EQUALS_EXPRESSION.toLowerCase()) ||
+                token.startsWith(RELATIONSHIP_EQUALS_EXPRESSION);
     }
 
 
@@ -71,6 +72,24 @@ private Set<ModelItem> evaluateExpression(String expr, DslContext context) {
             } else {
                 modelItems.addAll(parseIdentifier(expr, context));
             }
+        } else if (expr.startsWith(ELEMENT_NOT_EQUALS_EXPRESSION)) {
+            expr = expr.substring(ELEMENT_NOT_EQUALS_EXPRESSION.length());
+
+            if (isExpression(expr)) {
+                Set<ModelItem> mi = evaluateExpression(expr, context);
+                context.getWorkspace().getModel().getElements().forEach(element -> {
+                    if (!mi.contains(element)) {
+                        modelItems.add(element);
+                    }
+                });
+            } else {
+                Set<ModelItem> mi = parseIdentifier(expr, context);
+                context.getWorkspace().getModel().getElements().forEach(element -> {
+                    if (!mi.contains(element)) {
+                        modelItems.add(element);
+                    }
+                });
+            }
         } else if (expr.startsWith(RELATIONSHIP_EQUALS_EXPRESSION)) {
             expr = expr.substring(RELATIONSHIP_EQUALS_EXPRESSION.length());
 

structurizr-dsl/src/main/java/com/structurizr/dsl/StructurizrDslExpressions.java

@@ -10,6 +10,7 @@ class StructurizrDslExpressions {
     static final String ELEMENT_PROPERTY_EQUALS_EXPRESSION = "element\\.properties\\[.*]==.*";
 
     static final String ELEMENT_EQUALS_EXPRESSION = "element==";
+    static final String ELEMENT_NOT_EQUALS_EXPRESSION = "element!=";
     static final String ELEMENT_PARENT_EQUALS_EXPRESSION = "element.parent==";
 
     static final String RELATIONSHIP_TAG_EQUALS_EXPRESSION = "relationship.tag==";

structurizr-dsl/src/test/java/com/structurizr/dsl/ExpressionParserTests.java

@@ -541,4 +541,47 @@ void test_parseExpression_ReturnsRelationshipsAndImpliedRelationships_WhenUsingA
         assertTrue(relationships.contains(impliedRelationship));
     }
 
+    @Test
+    void test_parseExpression_ReturnsElements_WhenUsingElementNotEqualsIdentifier() {
+        SoftwareSystem a = model.addSoftwareSystem("A");
+        SoftwareSystem b = model.addSoftwareSystem("B");
+        SoftwareSystem c = model.addSoftwareSystem("C");
+
+        SystemLandscapeViewDslContext context = new SystemLandscapeViewDslContext(null);
+        context.setWorkspace(workspace);
+
+        IdentifiersRegister map = new IdentifiersRegister();
+        map.register("a", a);
+        map.register("b", b);
+        map.register("c", c);
+        context.setIdentifierRegister(map);
+
+        Set<ModelItem> elements = parser.parseExpression("element!=c", context);
+        assertEquals(2, elements.size());
+        assertTrue(elements.contains(a));
+        assertTrue(elements.contains(b));
+    }
+
+    @Test
+    void test_parseExpression_ReturnsElements_WhenUsingElementNotEqualsExpression() {
+        SoftwareSystem a = model.addSoftwareSystem("A");
+        SoftwareSystem b = model.addSoftwareSystem("B");
+        SoftwareSystem c = model.addSoftwareSystem("C");
+        Relationship aToB = a.uses(b, "Uses");
+        Relationship bToC = b.uses(c, "Uses");
+
+        SystemLandscapeViewDslContext context = new SystemLandscapeViewDslContext(null);
+        context.setWorkspace(workspace);
+
+        IdentifiersRegister map = new IdentifiersRegister();
+        map.register("a", a);
+        map.register("b", b);
+        map.register("c", c);
+        context.setIdentifierRegister(map);
+
+        Set<ModelItem> elements = parser.parseExpression("element!=->b", context);
+        assertEquals(1, elements.size());
+        assertTrue(elements.contains(c));
+    }
+
 }