Package org.gradle.api

Interface Task

All Superinterfaces:
Comparable<Task>, ExtensionAware
All Known Subinterfaces:
ObjectFilesToBinary
All Known Implementing Classes:
AbstractArchiveTask, AbstractCompile, AbstractCopyTask, AbstractDependencyReportTask, AbstractExecTask, AbstractLinkTask, AbstractNativeCompileTask, AbstractNativePCHCompileTask, AbstractNativeSourceCompileTask, AbstractPublishToMaven, AbstractReportTask, AbstractScalaCompile, org.gradle.api.internal.AbstractTask, AbstractTestTask, AntlrTask, AntTarget, ApiJar, Assemble, BrowserEvaluate, BuildEnvironmentReportTask, CCompile, Checkstyle, CodeNarc, CoffeeScriptCompile, CompareGradleBuilds, ComponentReport, org.gradle.api.internal.ConventionTask, Copy, CppCompile, CppPreCompiledHeaderCompile, CPreCompiledHeaderCompile, CreateStartScripts, CreateStartScripts, CreateStaticLibrary, DefaultTask, Delete, Depend, DependencyInsightReportTask, DependencyReportTask, DependentComponentsReport, Ear, Exec, FindBugs, GenerateBuildDashboard, GenerateCUnitLauncher, GenerateEclipseClasspath, GenerateEclipseJdt, GenerateEclipseProject, GenerateEclipseWtpComponent, GenerateEclipseWtpFacet, GenerateFiltersFileTask, GenerateIdeaModule, GenerateIdeaProject, GenerateIdeaWorkspace, GenerateIvyDescriptor, GenerateMavenPom, GenerateModuleMetadata, GeneratePluginDescriptors, GenerateProjectFileTask, GenerateSchemeFileTask, GenerateSolutionFileTask, GenerateWorkspaceSettingsFileTask, GenerateXcodeProjectFileTask, GenerateXcodeWorkspaceFileTask, GeneratorTask, GradleBuild, GroovyCompile, Groovydoc, HtmlDependencyReportTask, InitBuild, InstallExecutable, InstallXCTestBundle, JacocoBase, JacocoCoverageVerification, JacocoMerge, JacocoReport, JacocoReportBase, Jar, Jar, JavaCompile, Javadoc, JavaExec, JavaScriptMinify, JDepend, JsHint, LinkExecutable, LinkMachOBundle, LinkSharedLibrary, ModelReport, ObjectiveCCompile, ObjectiveCppCompile, ObjectiveCppPreCompiledHeaderCompile, ObjectiveCPreCompiledHeaderCompile, PlatformJavaCompile, PlatformScalaCompile, PlayCoffeeScriptCompile, PlayRun, PluginUnderTestMetadata, Pmd, PrefixHeaderFileGenerateTask, ProcessResources, ProjectReportTask, PropertiesGeneratorTask, PropertyListGeneratorTask, PropertyReportTask, PublishToIvyRepository, PublishToMavenLocal, PublishToMavenRepository, RhinoShellExec, RoutesCompile, RunTestExecutable, ScalaCompile, ScalaDoc, Sign, SourceTask, SwiftCompile, Sync, Tar, TaskReportTask, Test, TestReport, TwirlCompile, UnexportMainSymbol, Upload, ValidateTaskProperties, War, WindowsResourceCompile, Wrapper, WriteProperties, XcTest, XmlGeneratorTask, Zip
public interface Task extends Comparable<Task>, ExtensionAware

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 TaskContainer to create and lookup task instances. For example, TaskContainer.create(String) 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 }

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 ":" 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 Action.execute(T). You can add actions to a task by calling doFirst(Action) or doLast(Action).

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(groovy.lang.Closure) or doLast(groovy.lang.Closure).

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 StopActionException. A task action can abort execution of the task and continue to the next task by throwing a 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(Object...) or setDependsOn(Iterable), and mustRunAfter(Object...), setMustRunAfter(Iterable), shouldRunAfter(Object...) and setShouldRunAfter(Iterable) 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.
  • A Task.
  • A closure. The closure may take a Task as parameter. It 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 TaskDependency object.
  • A Buildable object.
  • A RegularFileProperty or DirectoryProperty.
  • 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.

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(String) method. You can change the value of these properties by calling the setProperty(String, Object) 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 convention properties added to the task by plugins. A plugin can add properties and methods to a task through the task's Convention object. The properties of this scope may be readable or writable, depending on the convention objects.
  • 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.

Dynamic Methods

A Plugin may add methods to a Task using its Convention object.

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.

  • Field Details

  • Method Details

    • getName

      @Internal String getName()

      Returns the name of this task. The name uniquely identifies the task within its Project.

      Returns:
      The name of the task. Never returns null.

    • getProject

      @Internal Project getProject()

      Returns the Project which this task belongs to.

      Returns:
      The project this task belongs to. Never returns null.

    • getActions

      @Internal List<Action<? super Task>> getActions()

      Returns the sequence of Action objects which will be executed by this task, in the order of execution.

      Returns:
      The task actions in the order they are executed. Returns an empty list if this task has no actions.

    • setActions

      void setActions(List<Action<? super Task>> actions)

      Sets the sequence of Action objects which will be executed by this task.

      Parameters:
      actions - The actions.

    • getTaskDependencies

      @Internal TaskDependency getTaskDependencies()

      Returns a TaskDependency which contains all the tasks that this task depends on.

      Returns:
      The dependencies of this task. Never returns null.

    • getDependsOn

      @Internal Set<Object> getDependsOn()

      Returns the dependencies of this task.

      Returns:
      The dependencies of this task. Returns an empty set if this task has no dependencies.

    • setDependsOn

      void setDependsOn(Iterable<?> dependsOnTasks)

      Sets the dependencies of this task. See here for a description of the types of objects which can be used as task dependencies.

      Parameters:
      dependsOnTasks - The set of task paths.

    • dependsOn

      Task dependsOn(Object... paths)

      Adds the given dependencies to this task. See here for a description of the types of objects which can be used as task dependencies.

      Parameters:
      paths - The dependencies to add to this task. The path can be defined by:
      • 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.
      • A Task.
      • A closure. The closure may take a Task as parameter. It 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 TaskDependency object.
      • A TaskReference object.
      • A Buildable object.
      • A RegularFileProperty or DirectoryProperty.
      • 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.
      • Anything else is treated as a failure.
      Returns:
      the task object this method is applied to

    • onlyIf

      void onlyIf(Closure onlyIfClosure)

      Execute the task only if the given closure returns true. The closure will be evaluated at task execution time, not during configuration. The closure will be passed a single parameter, this task. If the closure returns false, the task will be skipped.

      You may add multiple such predicates. The task is skipped if any of the predicates return false.

      Typical usage:myTask.onlyIf{ dependsOnTaskDidWork() }

      Parameters:
      onlyIfClosure - code to execute to determine if task should be run

    • onlyIf

      void onlyIf(Spec<? super Task> onlyIfSpec)

      Execute the task only if the given spec is satisfied. The spec will be evaluated at task execution time, not during configuration. If the Spec is not satisfied, the task will be skipped.

      You may add multiple such predicates. The task is skipped if any of the predicates return false.

      Typical usage (from Java):

      myTask.onlyIf(new Spec<Task>() {
    boolean isSatisfiedBy(Task task) {
       return task.dependsOnTaskDidWork();
    }
 });
      Parameters:
      onlyIfSpec - specifies if a task should be run

    • setOnlyIf

      void setOnlyIf(Closure onlyIfClosure)

      Execute the task only if the given closure returns true. The closure will be evaluated at task execution time, not during configuration. The closure will be passed a single parameter, this task. If the closure returns false, the task will be skipped.

      The given predicate replaces all such predicates for this task.

      Parameters:
      onlyIfClosure - code to execute to determine if task should be run

    • setOnlyIf

      void setOnlyIf(Spec<? super Task> onlyIfSpec)

      Execute the task only if the given spec is satisfied. The spec will be evaluated at task execution time, not during configuration. If the Spec is not satisfied, the task will be skipped.

      The given predicate replaces all such predicates for this task.

      Parameters:
      onlyIfSpec - specifies if a task should be run

    • getState

      @Internal TaskState getState()
      Returns the execution state of this task. This provides information about the execution of this task, such as whether it has executed, been skipped, has failed, etc.
      Returns:
      The execution state of this task. Never returns null.

    • setDidWork

      void setDidWork(boolean didWork)
      Sets whether the task actually did any work. Most built-in tasks will set this automatically, but it may be useful to manually indicate this for custom user tasks.

      This is useful when combined with onlyIf { dependsOnTaskDidWork() }.

      Parameters:
      didWork - indicates if the task did any work

    • getDidWork

      @Internal boolean getDidWork()

      Checks if the task actually did any work. Even if a Task executes, it may determine that it has nothing to do. For example, a compilation task may determine that source files have not changed since the last time a the task was run.

      Returns:
      true if this task did any work

    • getPath

      @Internal String getPath()

      Returns the path of the task, which is a fully qualified name for the task. The path of a task is the path of its Project plus the name of the task, separated by :.

      Returns:
      the path of the task, which is equal to the path of the project plus the name of the task.

    • doFirst

      Task doFirst(Action<? super Task> action)

      Adds the given Action to the beginning of this task's action list.

      Parameters:
      action - The action to add
      Returns:
      the task object this method is applied to

    • doFirst

      Task doFirst(Closure action)

      Adds the given closure to the beginning of this task's action list. The closure is passed this task as a parameter when executed.

      Parameters:
      action - The action closure to execute.
      Returns:
      This task.

    • doFirst

      @Incubating Task doFirst(String actionName, Action<? super Task> action)

      Adds the given Action to the beginning of this task's action list.

      Parameters:
      actionName - An arbitrary string that is used for logging.
      action - The action to add
      Returns:
      the task object this method is applied to
      Since:
      4.2

    • doLast

      Task doLast(Action<? super Task> action)

      Adds the given Action to the end of this task's action list.

      Parameters:
      action - The action to add.
      Returns:
      the task object this method is applied to

    • doLast

      @Incubating Task doLast(String actionName, Action<? super Task> action)

      Adds the given Action to the end of this task's action list.

      Parameters:
      actionName - An arbitrary string that is used for logging.
      action - The action to add.
      Returns:
      the task object this method is applied to
      Since:
      4.2

    • doLast

      Task doLast(Closure action)

      Adds the given closure to the end of this task's action list. The closure is passed this task as a parameter when executed.

      Parameters:
      action - The action closure to execute.
      Returns:
      This task.

    • leftShift

      @Deprecated Task leftShift(Closure action)
      Deprecated.
      Use doLast(Closure action)

      Adds the given closure to the end of this task's action list. The closure is passed this task as a parameter when executed. You can call this method from your build script using the << left shift operator.

      Parameters:
      action - The action closure to execute.
      Returns:
      This task.

    • deleteAllActions

      Task deleteAllActions()

      Removes all the actions of this task.

      Returns:
      the task object this method is applied to

    • getEnabled

      @Internal boolean getEnabled()

      Returns if this task is enabled or not.

      See Also:

    • setEnabled

      void setEnabled(boolean enabled)

      Set the enabled state of a task. If a task is disabled none of the its actions are executed. Note that disabling a task does not prevent the execution of the tasks which this task depends on.

      Parameters:
      enabled - The enabled state of this task (true or false)

    • configure

      Task configure(Closure configureClosure)

      Applies the statements of the closure against this task object. The delegate object for the closure is set to this task.

      Parameters:
      configureClosure - The closure to be applied (can be null).
      Returns:
      This task

    • getAnt

      @Internal AntBuilder getAnt()

      Returns the AntBuilder for this task. You can use this in your build file to execute ant tasks.

      Returns:
      The AntBuilder

    • getLogger

      @Internal Logger getLogger()

      Returns the logger for this task. You can use this in your build file to write log messages.

      Returns:
      The logger. Never returns null.

    • getLogging

      @Internal LoggingManager getLogging()
      Returns the LoggingManager which can be used to receive logging and to control the standard output/error capture for this task. By default, System.out is redirected to the Gradle logging system at the QUIET log level, and System.err is redirected at the ERROR log level.
      Returns:
      the LoggingManager. Never returns null.

    • property

      @Nullable Object property(String propertyName) throws MissingPropertyException

      Returns the value of the given property of this task. This method locates a property as follows:

      1. If this task object has a property with the given name, return the value of the property.
      2. If this task has an extension with the given name, return the extension.
      3. If this task's convention object has a property with the given name, return the value of the property.
      4. If this task has an extra property with the given name, return the value of the property.
      5. If not found, throw MissingPropertyException
      Parameters:
      propertyName - The name of the property.
      Returns:
      The value of the property, possibly null.
      Throws:
      MissingPropertyException - When the given property is unknown.

    • hasProperty

      boolean hasProperty(String propertyName)

      Determines if this task has the given property. See here for details of the properties which are available for a task.

      Parameters:
      propertyName - The name of the property to locate.
      Returns:
      True if this project has the given property, false otherwise.

    • setProperty

      void setProperty(String name, Object value) throws MissingPropertyException

      Sets a property of this task. This method searches for a property with the given name in the following locations, and sets the property on the first location where it finds the property.

      1. The task object itself. For example, the enabled project property.
      2. The task's convention object.
      3. The task's extra properties.
      If the property is not found, a MissingPropertyException is thrown.
      Parameters:
      name - The name of the property
      value - The value of the property
      Throws:
      MissingPropertyException

    • getConvention

      @Internal Convention getConvention()

      Returns the Convention object for this task. A Plugin can use the convention object to contribute properties and methods to this task.

      Returns:
      The convention object. Never returns null.

    • getDescription

      @Internal @Nullable String getDescription()
      Returns the description of this task.
      Returns:
      the description. May return null.

    • setDescription

      void setDescription(@Nullable String description)
      Sets a description for this task. This should describe what the task does to the user of the build. The description will be displayed when gradle tasks is called.
      Parameters:
      description - The description of the task. Might be null.

    • getGroup

      @Internal @Nullable String getGroup()
      Returns the task group which this task belongs to. The task group is used in reports and user interfaces to group related tasks together when presenting a list of tasks to the user.
      Returns:
      The task group for this task. Might be null.

    • setGroup

      void setGroup(@Nullable String group)
      Sets the task group which this task belongs to. The task group is used in reports and user interfaces to group related tasks together when presenting a list of tasks to the user.
      Parameters:
      group - The task group for this task. Can be null.

    • dependsOnTaskDidWork

      @Deprecated boolean dependsOnTaskDidWork()
      Deprecated.
      Build logic should not depend on this information about a task. Instead, declare task inputs and outputs to allow Gradle to optimize task execution.

      Checks if any of the tasks that this task depends on didWork.

      Returns:
      true if any task this task depends on did work.

    • getInputs

      @Internal TaskInputs getInputs()

      Returns the inputs of this task.

      Returns:
      The inputs. Never returns null.

    • getOutputs

      @Internal TaskOutputs getOutputs()

      Returns the outputs of this task.

      Returns:
      The outputs. Never returns null.

    • getDestroyables

      @Incubating @Internal TaskDestroyables getDestroyables()

      Returns the destroyables of this task.

      Returns:
      The destroyables. Never returns null.
      Since:
      4.0

    • getLocalState

      @Incubating TaskLocalState getLocalState()
      Returns the local state of this task.
      Since:
      4.3

    • getTemporaryDir

      @Internal File getTemporaryDir()

      Returns a directory which this task can use to write temporary files to. Each task instance is provided with a separate temporary directory. There are no guarantees that the contents of this directory will be kept beyond the execution of the task.

      Returns:
      The directory. Never returns null. The directory will already exist.

    • mustRunAfter

      @Incubating Task mustRunAfter(Object... paths)

      Specifies that this task must run after all of the supplied tasks.

       task taskY {
     mustRunAfter "taskX"
 }

      For each supplied task, this action adds a task 'ordering', and does not specify a 'dependency' between the tasks. As such, it is still possible to execute 'taskY' without first executing the 'taskX' in the example.

      See here for a description of the types of objects which can be used to specify an ordering relationship.

      Parameters:
      paths - The tasks this task must run after.
      Returns:
      the task object this method is applied to

    • setMustRunAfter

      @Incubating void setMustRunAfter(Iterable<?> mustRunAfter)

      Specifies the set of tasks that this task must run after.

       task taskY {
     mustRunAfter = ["taskX1", "taskX2"]
 }

      For each supplied task, this action adds a task 'ordering', and does not specify a 'dependency' between the tasks. As such, it is still possible to execute 'taskY' without first executing the 'taskX' in the example.

      See here for a description of the types of objects which can be used to specify an ordering relationship.

      Parameters:
      mustRunAfter - The set of task paths this task must run after.

    • getMustRunAfter

      @Incubating @Internal TaskDependency getMustRunAfter()

      Returns tasks that this task must run after.

      Returns:
      The tasks that this task must run after. Returns an empty set if this task has no tasks it must run after.

    • finalizedBy

      @Incubating Task finalizedBy(Object... paths)

      Adds the given finalizer tasks for this task.

       task taskY {
     finalizedBy "taskX"
 }

      See here for a description of the types of objects which can be used to specify a finalizer task.

      Parameters:
      paths - The tasks that finalize this task.
      Returns:
      the task object this method is applied to

    • setFinalizedBy

      @Incubating void setFinalizedBy(Iterable<?> finalizedBy)

      Specifies the set of finalizer tasks for this task.

       task taskY {
     finalizedBy = ["taskX1", "taskX2"]
 }

      See here for a description of the types of objects which can be used to specify a finalizer task.

      Parameters:
      finalizedBy - The tasks that finalize this task.

    • getFinalizedBy

      @Incubating @Internal TaskDependency getFinalizedBy()

      Returns tasks that finalize this task.

      Returns:
      The tasks that finalize this task. Returns an empty set if there are no finalising tasks for this task.

    • shouldRunAfter

      @Incubating TaskDependency shouldRunAfter(Object... paths)

      Specifies that this task should run after all of the supplied tasks.

       task taskY {
     shouldRunAfter "taskX"
 }

      For each supplied task, this action adds a task 'ordering', and does not specify a 'dependency' between the tasks. As such, it is still possible to execute 'taskY' without first executing the 'taskX' in the example.

      See here for a description of the types of objects which can be used to specify an ordering relationship.

      Parameters:
      paths - The tasks this task should run after.
      Returns:
      the task object this method is applied to

    • setShouldRunAfter

      @Incubating void setShouldRunAfter(Iterable<?> shouldRunAfter)

      Specifies the set of tasks that this task should run after.

       task taskY {
     shouldRunAfter = ["taskX1", "taskX2"]
 }

      For each supplied task, this action adds a task 'ordering', and does not specify a 'dependency' between the tasks. As such, it is still possible to execute 'taskY' without first executing the 'taskX' in the example.

      See here for a description of the types of objects which can be used to specify an ordering relationship.

      Parameters:
      shouldRunAfter - The set of task paths this task should run after.

    • getShouldRunAfter

      @Incubating @Internal TaskDependency getShouldRunAfter()

      Returns tasks that this task should run after.

      Returns:
      The tasks that this task should run after. Returns an empty set if this task has no tasks it must run after.