One of the great things of Gradle is that the build scripts are code. We can use all the features of the Groovy language, we can refactor our build scripts to make them more maintainable, we can use variables and properties to define values and much more, just like our application code. In this post we see how we can create a class to define a version in our build script. To set the version of a Gradle project we only have to assign a value to the version property. Normally we use a String value, but we can also assign an object. Gradle will use the toString() method of the object to get the String value for a version. In the following build script we define a new class Version in our build script. We create an instance of the class and assign it to the version property. With the task printVersion we can see the value of the version property:

version = new Version(major: 2, minor: 1, revision: 14)

task printVersion {
    doFirst {
        println "Project version is $version"
    }
}

defaultTasks 'printVersion'

class Version {
    int major, minor, revision

    String toString() {
        "$major.$minor.$revision"
    }
}

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The Google Guava libraries has many useful classes and methods. Normally I write code in Groovy and I am used to working with collections in an intuitive way. But sometimes I need to work with Java on my project and then the Google Guava libraries are a great alternative. Suppose I want to check if all elements in a collection apply to a certain condition. In Groovy I would write this:

final List list = ['Groovy', 'Rocks']

assert list.every { it.contains('o') }

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