Gradle scripts are configuration scripts that when executes configures an object of a particular type e.g. a build script executes and configures an object of type Project. This object is called delegate object of the script.
A build script is made up of zero or more statements (method calls, assignments, variables) and script blocks (e.g. allprojects{}, dependencies{}, artifacts{})
Script Block is a method call that takes a closure as an argument.
Closure is a standalone block of code which can take arguments, return values and assigned to a variable. The real value of closures is an ability to pass closure to different methods.
Gradle has two basic concepts: projects and tasks. A project can represent a library, web application or a thing to be deployed to staging/production. It is not necessarily always representing something that is built.
Task represents some atomic piece of work which a build performs e.g. compiling classes, create a JAR, generate javadoc or publish some archive to a repository.
apply plugin: is used for plugins using an id
apply from: is used for plugins from a path to a local file system or a URL to a remote location. It calls the script directly as if it was part of the build file
api - used for dependencies that are exposed to external modules (transitive dependency). As the dependency is exposed to external modules, change would be a more significant re-compiling effort as everyone needs to be informed about the change
implementation - used for dependencies that are internal to the component (not transitive dependency)
testImplementation - used for dependencies that are required to compile and run the test source of the project
compileOnly - used for dependencies required at compile time but never required at runtime e.g. source-only annotations. They won't be included on the runtime classpath and are non-transitive i.e. they are not exposed externally
settings.gradle - for settings that are build related & not necessarily project related, has access to Gradle delegate object
gradle.properties - used for project wide gradle settings, allows simple key-value storage in the form of strings, automatically included in the scope of the Project object
ext - used to define extra properties for Project object, shorthand for project.ext
./gradlew app:dependencies
- Gradle Tutorial https://www.vogella.com/tutorials/GradleTutorial/article.html
- https://tomgregory.com/gradle-implementation-vs-compile-dependencies/ (good explanation of compileOnly vs implementation vs runtimeOnly)