DependencyHandler

Table of Contents

Advanced dependency configuration
Dependency notations
Properties
Methods
Script blocks
Property details
Method details
API Documentation:DependencyHandler

A DependencyHandler is used to declare dependencies. Dependencies are grouped into configurations (see Configuration).

To declare a specific dependency for a configuration you can use the following syntax:

dependencies {
    configurationName dependencyNotation
}

Example shows a basic way of declaring dependencies. 

apply plugin: 'java'
//so that we can use 'implementation', 'testImplementation' for dependencies

dependencies {
  //for dependencies found in artifact repositories you can use
  //the group:name:version notation
  implementation 'commons-lang:commons-lang:2.6'
  testImplementation 'org.mockito:mockito:1.9.0-rc1'

  //map-style notation:
  implementation group: 'com.google.code.guice', name: 'guice', version: '1.0'

  //declaring arbitrary files as dependencies
  implementation files('hibernate.jar', 'libs/spring.jar')

  //putting all jars from 'libs' onto compile classpath
  implementation fileTree('libs')
}

Advanced dependency configuration

To do some advanced configuration on a dependency when it is declared, you can additionally pass a configuration closure:

dependencies {
    configurationName(dependencyNotation){
        configStatement1
        configStatement2
    }
}

Examples of advanced dependency declaration including:

  • Forcing certain dependency version in case of the conflict.
  • Excluding certain dependencies by name, group or both. More details about per-dependency exclusions can be found in docs for ModuleDependency.exclude(java.util.Map).
  • Avoiding transitive dependencies for certain dependency.
apply plugin: 'java' //so that I can declare 'implementation' dependencies

dependencies {
  implementation('org.hibernate:hibernate:3.1') {
    //in case of versions conflict '3.1' version of hibernate wins:
    force = true

    //excluding a particular transitive dependency:
    exclude module: 'cglib' //by artifact name
    exclude group: 'org.jmock' //by group
    exclude group: 'org.unwanted', module: 'iAmBuggy' //by both name and group

    //disabling all transitive dependencies of this dependency
    transitive = false
  }
}

More examples of advanced configuration, useful when dependency module has multiple artifacts: 

apply plugin: 'java' //so that I can declare 'implementation' dependencies

dependencies {
  //configuring dependency to specific configuration of the module
  implementation configuration: 'someConf', group: 'org.someOrg', name: 'someModule', version: '1.0'

  //configuring dependency on 'someLib' module
  implementation(group: 'org.myorg', name: 'someLib', version:'1.0') {
    //explicitly adding the dependency artifact:
    artifact {
      //useful when some artifact properties unconventional
      name = 'someArtifact' //artifact name different than module name
      extension = 'someExt'
      type = 'someType'
      classifier = 'someClassifier'
    }
  }
}

Dependency notations

There are several supported dependency notations. These are described below. For each dependency declared this way, a Dependency object is created. You can use this object to query or further configure the dependency.

You can also always add instances of Dependency directly:

configurationName <instance>

External dependencies

There are two notations supported for declaring a dependency on an external module. One is a string notation formatted this way:

configurationName "group:name:version:classifier@extension"

The other is a map notation:

configurationName group: group, name: name, version: version, classifier: classifier, ext: extension

In both notations, all properties, except name, are optional.

External dependencies are represented by a ExternalModuleDependency.

apply plugin: 'java'
//so that we can use 'implementation', 'testImplementation' for dependencies

dependencies {
  //for dependencies found in artifact repositories you can use
  //the string notation, e.g. group:name:version
  implementation 'commons-lang:commons-lang:2.6'
  testImplementation 'org.mockito:mockito:1.9.0-rc1'

  //map notation:
  implementation group: 'com.google.code.guice', name: 'guice', version: '1.0'
}

Project dependencies

To add a project dependency, you use the following notation:

configurationName project(':someProject')

The notation project(':projectA') is similar to the syntax you use when configuring a projectA in a multi-module gradle project.

By default, when you declare dependency to projectA, you actually declare dependency to the 'default' configuration of the projectA. If you need to depend on a specific configuration of projectA, use map notation for projects:

configurationName project(path: ':projectA', configuration: 'someOtherConfiguration')

Project dependencies are represented using a ProjectDependency.

File dependencies

You can also add a dependency using a FileCollection:

configurationName files('a file') 

apply plugin: 'java'
//so that we can use 'implementation', 'testImplementation' for dependencies

dependencies {
  //declaring arbitrary files as dependencies
  implementation files('hibernate.jar', 'libs/spring.jar')

  //putting all jars from 'libs' onto compile classpath
  implementation fileTree('libs')
}

File dependencies are represented using a SelfResolvingDependency.

Dependencies to other configurations

You can add a dependency using a Configuration.

When the configuration is from the same project as the target configuration, the target configuration is changed to extend from the provided configuration.

When the configuration is from a different project, a project dependency is added.

Gradle distribution specific dependencies

It is possible to depend on certain Gradle APIs or libraries that Gradle ships with. It is particularly useful for Gradle plugin development. Example:

//Our Gradle plugin is written in groovy
apply plugin: 'groovy'
//now we can use the 'implementation' configuration for declaring dependencies

dependencies {
  //we will use the Groovy version that ships with Gradle:
  implementation localGroovy()

  //our plugin requires Gradle API interfaces and classes to compile:
  implementation gradleApi()

  //we will use the Gradle test-kit to test build logic:
  testImplementation gradleTestKit()
}

Client module dependencies

To add a client module to a configuration you can use the notation:

configurationName module(moduleNotation) {
    module dependencies
}

The module notation is the same as the dependency notations described above, except that the classifier property is not available. Client modules are represented using a ClientModule.

Properties

PropertyDescription
components

The component metadata handler for this project. The returned handler can be used for adding rules that modify the metadata of depended-on software components.

constraints
Incubating

The dependency constraint handler for this project.

modules

The component module metadata handler for this project. The returned handler can be used for adding rules that modify the metadata of depended-on software components.

Methods

MethodDescription
add(configurationName, dependencyNotation)

Adds a dependency to the given configuration.

add(configurationName, dependencyNotation, configureClosure)

Adds a dependency to the given configuration, and configures the dependency using the given closure.

components(configureAction)

Configures component metadata for this project.

constraints(configureAction)
Incubating

Configures dependency constraint for this project.

create(dependencyNotation)

Creates a dependency without adding it to a configuration.

create(dependencyNotation, configureClosure)

Creates a dependency without adding it to a configuration, and configures the dependency using the given closure.

createArtifactResolutionQuery()

Creates an artifact resolution query.

enforcedPlatform(notation)
Incubating

Declares a dependency on an enforced platform. If the target coordinates represent multiple potential components, the platform component will be selected, instead of the library. An enforced platform is a platform for which the direct dependencies are forced, meaning that they would override any other version found in the graph.

enforcedPlatform(notation, configureAction)
Incubating

Declares a dependency on an enforced platform. If the target coordinates represent multiple potential components, the platform component will be selected, instead of the library. An enforced platform is a platform for which the direct dependencies are forced, meaning that they would override any other version found in the graph.

gradleApi()

Creates a dependency on the API of the current version of Gradle.

gradleTestKit()

Creates a dependency on the Gradle test-kit API.

localGroovy()

Creates a dependency on the Groovy that is distributed with the current version of Gradle.

module(notation)

Creates a dependency on a client module.

module(notation, configureClosure)

Creates a dependency on a client module. The dependency is configured using the given closure before it is returned.

modules(configureAction)

Configures module metadata for this project.

platform(notation)
Incubating

Declares a dependency on a platform. If the target coordinates represent multiple potential components, the platform component will be selected, instead of the library.

platform(notation, configureAction)
Incubating

Declares a dependency on a platform. If the target coordinates represent multiple potential components, the platform component will be selected, instead of the library.

project(notation)

Creates a dependency on a project.

Script blocks

No script blocks

Property details

ComponentMetadataHandler components (read-only)

The component metadata handler for this project. The returned handler can be used for adding rules that modify the metadata of depended-on software components.

DependencyConstraintHandler constraints (read-only)

Note: This property is incubating and may change in a future version of Gradle.

The dependency constraint handler for this project.

ComponentModuleMetadataHandler modules (read-only)

The component module metadata handler for this project. The returned handler can be used for adding rules that modify the metadata of depended-on software components.

Method details

Dependency add(String configurationName, Object dependencyNotation)

Adds a dependency to the given configuration.

Dependency add(String configurationName, Object dependencyNotation, Closure configureClosure)

Adds a dependency to the given configuration, and configures the dependency using the given closure.

void components(Action<? super ComponentMetadataHandler> configureAction)

Configures component metadata for this project.

This method executes the given action against the ComponentMetadataHandler for this project.

void constraints(Action<? super DependencyConstraintHandler> configureAction)

Note: This method is incubating and may change in a future version of Gradle.

Configures dependency constraint for this project.

This method executes the given action against the DependencyConstraintHandler for this project.

Dependency create(Object dependencyNotation)

Creates a dependency without adding it to a configuration.

Dependency create(Object dependencyNotation, Closure configureClosure)

Creates a dependency without adding it to a configuration, and configures the dependency using the given closure.

ArtifactResolutionQuery createArtifactResolutionQuery()

Creates an artifact resolution query.

Dependency enforcedPlatform(Object notation)

Note: This method is incubating and may change in a future version of Gradle.

Declares a dependency on an enforced platform. If the target coordinates represent multiple potential components, the platform component will be selected, instead of the library. An enforced platform is a platform for which the direct dependencies are forced, meaning that they would override any other version found in the graph.

Dependency enforcedPlatform(Object notation, Action<? super Dependency> configureAction)

Note: This method is incubating and may change in a future version of Gradle.

Declares a dependency on an enforced platform. If the target coordinates represent multiple potential components, the platform component will be selected, instead of the library. An enforced platform is a platform for which the direct dependencies are forced, meaning that they would override any other version found in the graph.

Dependency gradleApi()

Creates a dependency on the API of the current version of Gradle.

Dependency gradleTestKit()

Creates a dependency on the Gradle test-kit API.

Dependency localGroovy()

Creates a dependency on the Groovy that is distributed with the current version of Gradle.

Dependency module(Object notation)

Creates a dependency on a client module.

Dependency module(Object notation, Closure configureClosure)

Creates a dependency on a client module. The dependency is configured using the given closure before it is returned.

void modules(Action<? super ComponentModuleMetadataHandler> configureAction)

Configures module metadata for this project.

This method executes the given action against the ComponentModuleMetadataHandler for this project.

Dependency platform(Object notation)

Note: This method is incubating and may change in a future version of Gradle.

Declares a dependency on a platform. If the target coordinates represent multiple potential components, the platform component will be selected, instead of the library.

Dependency platform(Object notation, Action<? super Dependency> configureAction)

Note: This method is incubating and may change in a future version of Gradle.

Declares a dependency on a platform. If the target coordinates represent multiple potential components, the platform component will be selected, instead of the library.

Dependency project(Map<String, ?> notation)

Creates a dependency on a project.