Programming Groovy 2

16.3 Injecting Methods Using AST Transformations

We saw how to inject code into existing methods. We can also inject new methods and fields into classes by using AST transformations. This gives us the full power of aspect-oriented programming (AOP) at compile time without the need for any third-party libraries.

In the Execute Around Method pattern from Section 4.5, ​Using Closures for Resource Cleanup​, a ​static​ method helped create and clean up instances. This method yielded the instance for arbitrary use in between these two operations. Let’s implement that pattern using AST transformations. Rather than asking the programmer to implement the ​use​ method by hand, we can create it; the programmer just has to ask—nicely.

The AST transformations ...