VariableExpression apiVar = new VariableExpression(apiProperty, implementationNode);
BlockStatement ifBlock = new BlockStatement();
ArgumentListExpression arguments = new ArgumentListExpression();
arguments.addExpression(new ConstantExpression("Method on class ["+classNode+"] was used outside of a Grails application. If running in the context of a test using the mocking API or bootstrap Grails correctly."));
ifBlock.addStatement(new ThrowStatement(new ConstructorCallExpression(new ClassNode(IllegalStateException.class), arguments)));
BlockStatement elseBlock = new BlockStatement();
elseBlock.addStatement(new ReturnStatement(apiVar));
methodBody.addStatement(new IfStatement(new BooleanExpression(new BinaryExpression(apiVar, GrailsASTUtils.EQUALS_OPERATOR, GrailsASTUtils.NULL_EXPRESSION)),ifBlock,elseBlock));
MethodNode methodNode = new MethodNode(methodName, PUBLIC_STATIC_MODIFIER, implementationNode,ZERO_PARAMETERS,null,methodBody);