# Task

interface Task : Comparable<T> , ExtensionAware, Named

A `Task` represents a single atomic piece of work for a build, such as compiling classes or generating javadoc.

Each task belongs to a Project. You can use the various methods on to create and lookup task instances. For example, create creates an empty task with the given name. You can also use the `task` keyword in your build file:

    task myTask
    task myTask { configure closure }
    task myTask(type: SomeType)
    task myTask(type: SomeType) { configure closure }

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Each task has a name, which can be used to refer to the task within its owning project, and a fully qualified path, which is unique across all tasks in all projects. The path is the concatenation of the owning project's path and the task's name. Path elements are separated using the {@value org.gradle.api.Project#PATH_SEPARATOR} character.

## Task Actions

A `Task` is made up of a sequence of Action objects. When the task is executed, each of the actions is executed in turn, by calling execute. You can add actions to a task by calling doFirst or doLast.

Groovy closures can also be used to provide a task action. When the action is executed, the closure is called with the task as parameter. You can add action closures to a task by calling doFirst or doLast.

There are 2 special exceptions which a task action can throw to abort execution and continue without failing the build. A task action can abort execution of the action and continue to the next action of the task by throwing a org.gradle.api.tasks.StopActionException. A task action can abort execution of the task and continue to the next task by throwing a org.gradle.api.tasks.StopExecutionException. Using these exceptions allows you to have precondition actions which skip execution of the task, or part of the task, if not true.

## Task Dependencies and Task Ordering

A task may have dependencies on other tasks or might be scheduled to always run after another task. Gradle ensures that all task dependencies and ordering rules are honored when executing tasks, so that the task is executed after all of its dependencies and any "must run after" tasks have been executed.

Dependencies to a task are controlled using dependsOn or setDependsOn, and mustRunAfter, setMustRunAfter, shouldRunAfter and setShouldRunAfter are used to specify ordering between tasks. You can use objects of any of the following types to specify dependencies and ordering:

- A `String`, `CharSequence` or `groovy.lang.GString` task path or name. A relative path is interpreted relative to the task's Project. This allows you to refer to tasks in other projects. These task references will not cause task creation.
- A Task.
- A TaskDependency object.
- A org.gradle.api.tasks.TaskReference object.
- A Buildable object.
- A org.gradle.api.file.RegularFileProperty or org.gradle.api.file.DirectoryProperty.
- A Provider object. May contain any of the types listed here.
- A `Iterable`, `Collection`, `Map` or array. May contain any of the types listed here. The elements of the iterable/collection/map/array are recursively converted to tasks.
- A `Callable`. The `call()` method may return any of the types listed here. Its return value is recursively converted to tasks. A `null` return value is treated as an empty collection.
- A Groovy `Closure` or Kotlin function. The closure may take a `Task` as parameter. The closure or function may return any of the types listed here. Its return value is recursively converted to tasks. A `null` return value is treated as an empty collection.
- Anything else is treated as an error.

## Using a Task in a Build File

### Dynamic Properties

A `Task` has 4 'scopes' for properties. You can access these properties by name from the build file or by calling the property method. You can change the value of these properties by calling the setProperty method.

- The `Task` object itself. This includes any property getters and setters declared by the `Task` implementation class. The properties of this scope are readable or writable based on the presence of the corresponding getter and setter methods.
- The extensions added to the task by plugins. Each extension is available as a read-only property with the same name as the extension.
- The extra properties of the task. Each task object maintains a map of additional properties. These are arbitrary name -> value pairs which you can use to dynamically add properties to a task object. Once defined, the properties of this scope are readable and writable.

### Parallel Execution

By default, tasks are not executed in parallel unless a task is waiting on asynchronous work and another task (which is not dependent) is ready to execute. Parallel execution can be enabled by the `--parallel` flag when the build is initiated. In parallel mode, the tasks of different projects (i.e. in a multi project build) are able to be executed in parallel.

#### Inheritors

ObjectFilesToBinary
DefaultTask

## Properties

extra
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val ExtensionAware.extra: ExtraPropertiesExtension

The extra properties extension in this object's extension container.

TASK_ACTION
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val TASK_ACTION: String = "action"
TASK_CONSTRUCTOR_ARGS
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val TASK_CONSTRUCTOR_ARGS: String = "constructorArgs"
Constructor arguments for the Task
TASK_DEPENDS_ON
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val TASK_DEPENDS_ON: String = "dependsOn"
TASK_DESCRIPTION
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val TASK_DESCRIPTION: String = "description"
TASK_GROUP
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val TASK_GROUP: String = "group"
TASK_NAME
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val TASK_NAME: String = "name"
TASK_OVERWRITE
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val TASK_OVERWRITE: String = "overwrite"
TASK_TYPE
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val TASK_TYPE: String = "type"

## Functions

compareTo
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abstract fun compareTo(p: T): Int
configure
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abstract fun configure(configureClosure: Closure): Task
Applies the statements of the closure against this task object.
configure
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inline fun <T : Any> ExtensionAware.configure(noinline configuration: T.() -> Unit)

Executes the given configuration block against the extension of the specified type.

dependsOn
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abstract fun dependsOn(paths: Array<Any>): Task
Adds the given dependencies to this task.
doFirst
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abstract fun doFirst(@DelegatesTo(value = Task::class) action: Closure): Task
Adds the given closure to the beginning of this task's action list.
abstract fun doFirst(action: Action<in Task>): Task
abstract fun doFirst(actionName: String, action: Action<in Task>): Task
Adds the given Action to the beginning of this task's action list.
doLast
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abstract fun doLast(@DelegatesTo(value = Task::class) action: Closure): Task
Adds the given closure to the end of this task's action list.
abstract fun doLast(action: Action<in Task>): Task
abstract fun doLast(actionName: String, action: Action<in Task>): Task
Adds the given Action to the end of this task's action list.
doNotTrackState
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abstract fun doNotTrackState(reasonNotToTrackState: String)
Do not track the state of the task.
finalizedBy
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abstract fun finalizedBy(paths: Array<Any>): Task
Adds the given finalizer tasks for this task.
getActions
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@Internal
abstract fun getActions(): List<Action<in Task>>
Returns the sequence of Action objects which will be executed by this task, in the order of execution.
getAnt
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@Internal
abstract fun getAnt(): AntBuilder
Returns the `AntBuilder` for this task.
getDependsOn
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@Internal
abstract fun getDependsOn(): Set<Any>
Returns the dependencies of this task.
getDescription
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@Internal
@Nullable
abstract fun getDescription(): @Nullable String
Returns the description of this task.
getDestroyables
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@Internal
abstract fun getDestroyables(): TaskDestroyables
Returns the destroyables of this task.
getDidWork
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@Internal
abstract fun getDidWork(): Boolean
Checks if the task actually did any work.
getEnabled
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@Internal
abstract fun getEnabled(): Boolean
Returns if this task is enabled or not.
getExtensions
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abstract fun getExtensions(): ExtensionContainer
getFinalizedBy
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@Internal
abstract fun getFinalizedBy(): TaskDependency
Returns tasks that finalize this task.
getGroup
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@Internal
@Nullable
abstract fun getGroup(): @Nullable String
Returns the task group which this task belongs to.
getInputs
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@Internal
abstract fun getInputs(): TaskInputs
Returns the inputs of this task.
getLocalState
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@Internal
abstract fun getLocalState(): TaskLocalState
Returns the local state of this task.
getLogger
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@Internal
abstract fun getLogger(): Logger
Returns the logger for this task.
getLogging
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@Internal
abstract fun getLogging(): LoggingManager
Returns the org.gradle.api.logging.LoggingManager which can be used to receive logging and to control the standard output/error capture for this task.
getMustRunAfter
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@Internal
abstract fun getMustRunAfter(): TaskDependency
Returns tasks that this task must run after.
getName
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@Internal
abstract fun getName(): String
Returns the name of this task.
getOutputs
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@Internal
abstract fun getOutputs(): TaskOutputs
Returns the outputs of this task.
getPath
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@Internal
abstract fun getPath(): String
Returns the path of the task, which is a fully qualified name for the task.
getProject
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@Internal
abstract fun getProject(): Project
Returns the Project which this task belongs to.
getShouldRunAfter
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@Internal
abstract fun getShouldRunAfter(): TaskDependency
Returns tasks that this task should run after.
getState
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@Internal
abstract fun getState(): TaskState
Returns the execution state of this task.
getTaskDependencies
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@Internal
abstract fun getTaskDependencies(): TaskDependency
Returns a TaskDependency which contains all the tasks that this task depends on.
getTemporaryDir
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@Internal
abstract fun getTemporaryDir(): File
Returns a directory which this task can use to write temporary files to.
getTimeout
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@Internal
abstract fun getTimeout(): Property<Duration>
The timeout of this task.
hasProperty
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abstract fun hasProperty(propertyName: String): Boolean
Determines if this task has the given property.
mustRunAfter
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abstract fun mustRunAfter(paths: Array<Any>): Task
Specifies that this task must run after all of the supplied tasks.
notCompatibleWithConfigurationCache
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abstract fun notCompatibleWithConfigurationCache(reason: String)
Specifies that this task is not compatible with the configuration cache.
onlyIf
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abstract fun onlyIf(onlyIfClosure: Closure<out Any>)
Execute the task only if the given closure returns true.
abstract fun onlyIf(onlyIfSpec: Spec<in Task>)
@Incubating
abstract fun onlyIf(onlyIfReason: String, onlyIfSpec: Spec<in Task>)
Execute the task only if the given spec is satisfied.
property
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@Nullable
abstract fun property(propertyName: String): @Nullable Any
Returns the value of the given property of this task.
setActions
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abstract fun setActions(actions: List<Action<in Task>>)
Sets the sequence of Action objects which will be executed by this task.
setDependsOn
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abstract fun setDependsOn(dependsOnTasks: Iterable<out Any>)
Sets the dependencies of this task.
setDescription
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abstract fun setDescription(@Nullable description: @Nullable String)
Sets a description for this task.
setDidWork
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abstract fun setDidWork(didWork: Boolean)
Sets whether the task actually did any work.
setEnabled
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abstract fun setEnabled(enabled: Boolean)
Set the enabled state of a task.
setFinalizedBy
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abstract fun setFinalizedBy(finalizedBy: Iterable<out Any>)
Specifies the set of finalizer tasks for this task.
setGroup
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abstract fun setGroup(@Nullable group: @Nullable String)
Sets the task group which this task belongs to.
setMustRunAfter
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abstract fun setMustRunAfter(mustRunAfter: Iterable<out Any>)
Specifies the set of tasks that this task must run after.
setOnlyIf
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abstract fun setOnlyIf(onlyIfClosure: Closure<out Any>)
Execute the task only if the given closure returns true.
abstract fun setOnlyIf(onlyIfSpec: Spec<in Task>)
@Incubating
abstract fun setOnlyIf(onlyIfReason: String, onlyIfSpec: Spec<in Task>)
Execute the task only if the given spec is satisfied.
setProperty
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abstract fun setProperty(name: String, value: Any)
Sets a property of this task.
setShouldRunAfter
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abstract fun setShouldRunAfter(shouldRunAfter: Iterable<out Any>)
Specifies the set of tasks that this task should run after.
shouldRunAfter
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abstract fun shouldRunAfter(paths: Array<Any>): TaskDependency
Specifies that this task should run after all of the supplied tasks.
the
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inline fun <T : Any> ExtensionAware.the(): T

Returns the extension of the specified type.

fun <T : Any> ExtensionAware.the(extensionType: KClass<T>): T

Returns the extension of the specified extensionType.

usesService
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abstract fun usesService(service: Provider<out BuildService<out Any>>)
Registers a BuildService that is used by this task so its constraint on parallel execution can be honored.