Groovy Peek (G-Peek)

I have been working with a platform that supports dynamic code generation and loading. Groovy has been the choice of language for the dynamic code. The underlying platform has been Java/JVM stack.

Dynamic code does not get any love from the IDE breakpoints for debugging. Hence I used this approach of Groovy AST transformation to render the code execution as a snapshot in time to aid debugging.

Groovy support for AST and its usage has been very helpful.Glad that I choose Groovy as the language of choice for the dynamic code in the platform.

The code in this repository is a demonstration of the approach to peek into the function’s variables post execution. Helpful in determining the cause of the result obtained from the function.

Add an @intercept annotation as follows to the function whose rendering is needed.

 @Intercept
    BigDecimal payment() {
        def now = LocalDate.now()
        def march = isMarch(this, Date.valueOf(now))
        if (march) {
            return schoolFees + propertyTax
        }
        return servantPay
    }

And render the result post execution with @ShowResult annotation as follows

public java.math.BigDecimal payment() {
    java.lang.Object now = "java.time.LocalDate.now()=2019-08-19"
    java.lang.Object march = "IndividualPaymentCalculator.isMarch(java.sql.Date.valueOf(now=2019-08-19)=2019-08-19)=false"
    if ("march=false") {
        return schoolFees + propertyTax
    }
    return "servantPay=3000.0"
    "result=3000.0"
}

The rendering above is a snapshot,in time, of the method execution. The unit test provided in the repository demonstrates the usage.