Execute Groovy script from Gradle without compiling Java

Question

I have a Java project with Gradle. Also I use Groovy to generate some class that will be used in Java code. Gradle executes script in separate task below:

task generateClass(type: JavaExec) {
    classpath = sourceSets.main.runtimeClasspath
    main = 'generatorScript'
}

If I run this task, it first starts Java compilation, and only after that executes script. So if compilation failed, my generator script will not be executed. As it was mentioned, script generates one class, which my Java code is actually depends on, so, if not generated, Java will not be compiled. Vicious circle.

Script itself does not depend on some Java classes and is placed in separate sources directory:

/src
   /main
      /java
          /...(java classes)
      /groovy
          generatorScript.groovy

It seems like nothing interferes me to execute script separately and independently from Java compilation.

How can I achieve that?

Maybe it's possible to specify classpath manually and don't include Java classes in there (but what does it must contain?). In this case, Java compilation will be executed before Groovy anyway, but will not touch project classes. — Дмитрий Брикман
– Дмитрий Брикман, Commented Oct 17, 2018 at 7:46
if you have groovy installed just run it with system command groovy generatorScript.groovy. or with java java -cp groovy-all-x.x.x.jar groovy.ui.GroovyMain generatorScript.groovy — daggett
– daggett, Commented Oct 17, 2018 at 8:45

M.Ricciuti · Accepted Answer · 2018-10-17 07:46:43Z

2

The problem is that you have the generator groovy script in the main sourcesets, and you try to compile this groovy script to use it as classpath for your JavaExec task. This is why compileJava task is executed, I guess.

You could do in another way, using groovy.ui.GroovyMain to execute your script, with following solution based on this link

configurations {
    // a dedicated Configuration for Groovy classpath
    groovyScript
}

dependencies {
    // Set Groovy dependency so groovy.ui.GroovyMain can be found.
    groovyScript localGroovy()
}

task generateClass(type: JavaExec) {

    // Set class path used for running Groovy command line.
    classpath = configurations.groovyScript

    // Main class that runs the Groovy command line.
    main = 'groovy.ui.GroovyMain'

    // Pass your groovy script as argument of the GroovyMain main
    // (can be improved)
    args 'src/main/groovy/generatorScript.groovy'

}

answered Oct 17, 2018 at 7:46

M.Ricciuti

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1 Comment

Дмитрий Брикман Over a year ago

It works, thank you! It's strange that I have already tried this way, but for some reason unsuccessfully.

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