// Copied from org.eclipse.ocl.ecore.tests.DocumentationExamples.java

		Library library = getLibrary();  // get library from a hypothetical source

		OCLHelper<EClassifier, ?, ?, Constraint> helper = ocl.createOCLHelper();

		// use the constraints defined in the OCL document

		// use the getBooks() additional operation to find a book
		helper.setContext(EXTLibraryPackage.Literals.LIBRARY);
		OCLExpression<EClassifier> query = helper.createQuery(
		    "getBooks('Bleak House')->asSequence()->first()");

		Book book = (Book) ocl.evaluate(library, query);
		System.out.printf("Got book: %s%n", book);

		// use the unique_title constraint to validate the book
		System.out.printf("Validate book: %b%n",
		    ocl.check(book, constraintMap.get("unique_title")));