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[[part4_settings_file]]
= Part 4: Writing the Settings File

Learn the basics of authoring Gradle by developing the Settings File.

****
**In this section, you will:**

- Understand the Settings object
- Understand the Settings file
- Understand Gradle scripting
****

[[part4_begin]]
== Step 0. Before you Begin

1. You initialized your Java app in <<part1_gradle_init_project.adoc#part1_begin,part 1>>.
2. You understand the Gradle Build Lifecycle from <<part2_build_lifecycle.adoc#part2_begin,part 2>>.
3. You added a subproject and a separate Build in <<part3_multi_project_builds#part3_begin, part3>>.

[[ab_part4_step1]]
== Step 1. Gradle scripts

Build scripts and setting files are code.
They are written in Kotlin or Groovy.

You use the link:{kotlinDslPath}[Kotlin DSL], link:{groovyDslPath}[Groovy DSL] and link:{javadocPath}[Gradle APIs] to write the scripts.

The methods that can be used within a Gradle script primarily include:

- Gradle APIs - such as `getRootProject()` from the link:{javadocPath}/org/gradle/api/initialization/Settings.html[Settings API]
- Blocks defined in the DSL - such as the `plugins{}` block from link:{kotlinDslPath}/gradle/org.gradle.kotlin.dsl/-kotlin-settings-script/index.html[KotlinSettingsScript]
- Extensions defined by Plugins - such as `implementation()` and `api()` provided by the `java` plugin when applied

[[ab_part4_step2]]
== Step 2. The `Settings` object

The settings file is the entry point of every Gradle build.

During the initialization phase, Gradle finds the settings file in your project root directory.

When the settings file, `settings.gradle(.kts)`, is found, Gradle instantiates a link:{groovyDslPath}/org.gradle.api.initialization.Settings.html[Settings] object.

One of the purposes of the link:{groovyDslPath}/org.gradle.api.initialization.Settings.html[Settings] object is to allow you to declare all the projects to be included in the build.

You can use any of the methods and properties on the link:{groovyDslPath}/org.gradle.api.initialization.Settings.html[Settings] interface directly in your settings file.

For example:

[.multi-language-sample]
=====
[source, kotlin]
----
includeBuild("some-build")                         // Delegates to Settings.includeBuild()
reportsDir = findProject("/myInternalProject")     // Delegates to Settings.findProject()
----
=====
[.multi-language-sample]
=====
[source, groovy]
----
includeBuild('some-build')                         // Delegates to Settings.includeBuild()
reportsDir = findProject('/myInternalProject')     // Delegates to Settings.findProject()
----
=====

[[ab_part4_step3]]
== Step 3. The Settings file

Let's break down the settings file in our project root directory:

====
include::sample[dir="snippets/tutorials/authoring-builds/settingsFile-breakdown/kotlin",files="settings.gradle.kts[tags=settings-breakdown]"]
include::sample[dir="snippets/tutorials/authoring-builds/settingsFile-breakdown/groovy",files="settings.gradle[tags=settings-breakdown]"]
====
<1> `plugins({})` from the link:{groovyDslPath}/org.gradle.plugin.use.PluginDependenciesSpec.html[PluginDependenciesSpec API]
<2> `id()` method from the link:{groovyDslPath}/org.gradle.plugin.use.PluginDependenciesSpec.html[PluginDependenciesSpec API]
<3> `getRootProject()` method from the link:{groovyDslPath}/org.gradle.api.initialization.Settings.html[Settings API]
<4> `include()` method from the link:{groovyDslPath}/org.gradle.api.initialization.Settings.html[Settings API]
<5> `includeBuild()` method from the link:{groovyDslPath}/org.gradle.api.initialization.Settings.html[Settings API]

[.text-right]
**Next Step:** <<part5_build_scripts#part5_build_scripts,Writing a Build Script>> >>
