# DependencyConstraintHandler

API Documentation: | `DependencyConstraintHandler`

A `DependencyConstraintHandler` is used to declare dependency constraints.

### Dependency constraint notations

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

You can also always add instances of `DependencyConstraint` directly:

`configurationName(<instance>)`

Dependency constraints can also be declared with a `Provider` that provides any of the other supported dependency constraint notations.

#### External dependencies

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

`configurationName("group:name:version")`

The other is a map notation:

`configurationName(group: group, name: name, version: version)`

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

    plugins {
        id("java-library") // so that we can use 'implementation', 'testImplementation' for dependency constraints
    }

    dependencies {
      constraints {
        //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 constraint, you use the following notation:

`configurationName(project(":some-project"))`

### Properties

No properties

### Methods

Method | Description
`add(configurationName, dependencyNotation)` | Adds a dependency constraint to the given configuration.
`add(configurationName, dependencyNotation, configureAction)` | Adds a dependency constraint to the given configuration, and configures the dependency constraint using the given closure.
`create(dependencyConstraintNotation)` | Creates a dependency constraint without adding it to a configuration.
`create(dependencyConstraintNotation, configureAction)` | Creates a dependency constraint without adding it to a configuration, and configures the dependency constraint using the given closure.
`enforcedPlatform(notation)` | Declares a constraint 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)` | Declares a constraint 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.

### Script blocks

No script blocks

### Method details

#### `DependencyConstraint` `add`(`String` configurationName, `Object` dependencyNotation)

Adds a dependency constraint to the given configuration.

#### `DependencyConstraint` `add`(`String` configurationName, `Object` dependencyNotation, ``Action`<? super `DependencyConstraint`>` configureAction)

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

#### `DependencyConstraint` `create`(`Object` dependencyConstraintNotation)

Creates a dependency constraint without adding it to a configuration.

#### `DependencyConstraint` `create`(`Object` dependencyConstraintNotation, ``Action`<? super `DependencyConstraint`>` configureAction)

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

#### `DependencyConstraint` `enforcedPlatform`(`Object` notation)

Declares a constraint 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.

#### `DependencyConstraint` `enforcedPlatform`(`Object` notation, ``Action`<? super `DependencyConstraint`>` configureAction)

Declares a constraint 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.