Gradle Project and Build Script

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Gradle Project

Overview

A Project is the main API to use to interact with Gradle. All top level statements within a "build.gradle" build script are delegated to the corresponding Project instance and when executed, modify its state. The build.gradle configuration script is written in the Gradle DSL and it may contain any Groovy language element, variable declarations, script blocks, etc. Groovy single-quoted and double-quoted string literals can be used. The main difference is that double-quoted String literals support String interpolation.

In case of a multi-project build, It is possible to configure a project build from another build script associated with any project in the hierarchy. This capability is called cross-project configuration. Gradle implements cross-project configuration via configuration injection. Configuration injection is the default way to define common behavior.

build.gradle can be created automatically on project setup with gradle init. To make build scripts more concise, Gradle automatically adds the set of default Gradle import statements to the script.

The default name of the build script is "build.gradle" and in most cases there is no need to change it. It can be changed, though, in settings.gradle by setting the "buildFileName" property of the ProjectDescriptor associated with the project whose build script name we want to change:

project(':projectA').buildFileName = 'projectA.gradle'

The project is a collection of tasks.

Example

apply plugin: 'java'

// name comes from the directory name or it can be changed in settings.gradle
group = "playground.example"
version = "0.1.0"
description = "A Gradle example project"

repositories {
    mavenLocal()
    mavenCentral()
}

dependencies {
    implementation 'org.slf4j:slf4j-api:1.7.12'
    testImplementation 'junit:junit:4.+'
}

configurations {
    testImplementation.exclude group: 'com.example'
}

configurations.all {
    resolutionStrategy.cacheChangingModulesFor 3600, 'seconds'
}

compileJava {
    options.compilerArgs += ['-Xlint']
}

javadoc {
    options.charSet = 'UTF-8'
}

task runMain(type: JavaExec) {
    classpath = sourceSets.main.runtimeClasspath
    main = "io.novaordis.playground.gradle.java.Main"
}

Other Project Properties

Project Properties

Top-Level Script Blocks

allprojects{}

Applies the given configuration closure, in order, to the current project and all of its sub-projects.

allprojects{...} usage examples

subprojects{}

Applies the given configuration closure, in order, to all sub-projects of the current project.

subprojects{...} usage examples

buildscript{}

Used to specify external plugins:

External Plugins

configurations{}

Configures the dependencies configurations of this project. More details available in:

Gradle Dependencies and Dependency Configurations

dependencies{}

Declare the dependencies of the project. For more details see:

Gradle Dependencies and Dependency Configurations

repositories{}

Used to declare and configure the repositories associated with this project. The repositories declared here will only be used to pull dependencies from, not publish against. For details on how to specify publishing repositories, see Gradle Artifact Publishing. This method executes the given configuration closure against the RepositoryHandler for this project, which is passed to the closure as the closure's delegate. More details on on repositories and how to configured them are available in:

Gradle Repositories

Project's Containers and Handlers

https://docs.gradle.org/current/dsl/#N10272

• Repository Handler
• Configuration Container
• Publishing extension:
  • Publications Container
  • Publishing Repository Container

Multi-Project Builds

Gradle Multi-Project Builds

Reacting to Build Lifecycle Events

A build lifecycle can be reacted to with code similar to the following examples.

More research necessary.

allprojects {
      afterEvaluate { project ->
          if (project.hasTests) {
              println "Adding test task to $project"
              project.task('test') {
                   doLast {
                         println "running tests for $project"
                   }
              }
          }
     }
}

gradle.afterProject {project, projectState ->
      if (projectState.failure) {
          println "Evaluation of $project FAILED"
      } 
      else {
          println "Evaluation of $project succeeded"
      }
}

Text Execution Configuration

Test Execution Configuration