1 files changed, 32 insertions, 0 deletions
diff --git a/rba.tool.editor/src/rba/tool/editor/validation/validators/IsChangedDisplayValidator.xtend b/rba.tool.editor/src/rba/tool/editor/validation/validators/IsChangedDisplayValidator.xtend
new file mode 100644
index 0000000..55bd12e
--- /dev/null
+++ b/rba.tool.editor/src/rba/tool/editor/validation/validators/IsChangedDisplayValidator.xtend
@@ -0,0 +1,32 @@
+package rba.tool.editor.validation.validators
+
+import org.eclipse.xtext.validation.Check
+import org.eclipse.xtext.validation.EValidatorRegistrar
+import rba.core.RBACorePackage
+import rba.tool.editor.messages.Messages
+import rba.tool.editor.validation.AbstractRBAModelValidator
+import rba.view.IsChangedDisplay
+import rba.core.ExpressionType
+
+class IsChangedDisplayValidator extends AbstractRBAModelValidator {
+	private static final String OperatorName = IsChangedDisplay.simpleName
+
+	override register(EValidatorRegistrar registrar) {
+		// not needed for classes used as ComposedCheck
+	}
+
+	@Check(NORMAL)
+	def checkIsChangedDisplay(IsChangedDisplay isChangedDisplay) {
+		if (isChangedDisplay.operand.size > 1) {
+			error(String.format(Messages.OPERAND_SIZE_ONE, OperatorName), RBACorePackage.Literals.OPERATOR__OPERAND, 0)
+			return;
+		}
+
+		var firstOperand = isChangedDisplay.operand.get(0)
+		if (firstOperand.type != ExpressionType::AREA) {
+			error(String.format(Messages.FIRST_OPERAND_MUST_AREA, OperatorName),
+				RBACorePackage.Literals.OPERATOR__OPERAND, 0)
+			return;
+		}
+	}
+}