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Hi all, my name is Hubert A. Klein Ikkink. Not a very common name, right? To make things easier I just picked the first letters of my firstname and surname and came up with haki. So there you have it, now I am also known as Mr. Haki or mrhaki for short. You can read more blog postings at www.mrhaki.com. I am a passionate Groovy and Java developer based in Tilburg, The Netherlands. My goal is to write clean, elegant, user-centered and high quality software. You can find me on Google+ and Twitter. Hubert is a DZone MVB and is not an employee of DZone and has posted 151 posts at DZone. You can read more from them at their website. View Full User Profile

Groovy Goodness: BaseScript with Abstract Run Script Method

05.11.2014
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In a previous blog post we have seen how we can use a BaseScript AST transformation to set a base script class for running scripts. Since Groovy 2.3 we can apply the @BaseScript annotation on package and import statements. Also we can implement a run method in our Script class in which we call an abstract method. The abstract method will actually run the script, so we can execute code before and after the script code runs by implementing logic in the run method.

In the following sample we create a Script class CustomScript. We implement the run method and add the abstract method runCode:

// File: CustomScript.groovy
package com.mrhaki.groovy.blog

abstract class CustomScript extends Script {

    def run() {
        before()
        try {

            // Run actually script code.
            final result = runCode()

            println "Script says $result"
        } finally {
            println 'Script ended'
        }
    }

    private void before() {
        println 'Script starts'
    }

    // Abstract method as placeholder for
    // the actual script code to run.
    abstract def runCode()
}

Next we create a Groovy script where we use our new CustomScript class.

// File: Sample.groovy
// Since Groovy 2.3 we can apply the
// @BaseScript annotation on package
// and import statement.
@groovy.transform.BaseScript(com.mrhaki.groovy.blog.CustomScript)
package com.mrhaki.groovy.blog

// Script code:
final String value = 'Groovy rules'
assert value.size() == 12

// Return value
value

When we run our script we see the following output:

Before script runsScript says Groovy rulesScript ended

Code written with Groovy 2.3.

Published at DZone with permission of Hubert Klein Ikkink, author and DZone MVB. (source)

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