org.gradle.api
Interface Task

All Superinterfaces:
java.lang.Comparable<Task>
All Known Implementing Classes:
AbstractJettyRunTask, AbstractJettyRunWarTask, AbstractReportTask, org.gradle.api.internal.AbstractTask, AntTarget, Checkstyle, Clean, CodeNarc, Compile, org.gradle.api.internal.ConventionTask, Copy, org.gradle.api.DefaultTask, DependencyReportTask, EclipseClasspath, EclipseClean, EclipseProject, EclipseWtp, EclipseWtpModule, GroovyCompile, Groovydoc, Javadoc, JettyRun, JettyRunWar, JettyStop, PropertyReportTask, ScalaCompile, ScalaDefine, ScalaDoc, SourceTask, TaskReportTask, Test, Upload, Wrapper

public interface Task
extends java.lang.Comparable<Task>

A Task represents a single step of 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.add(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 myType << { task action }
 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 TaskAction 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) or using the left-shift << operator.

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.

Dependencies

A task may have dependencies on other tasks. Gradle ensures that tasks are executed in dependency order, so that the dependencies of a task are executed before the task is executed. You can add dependencies to a task using dependsOn(Object...) or setDependsOn(Iterable). You can add objects of any of the following types as a dependency:

Using a Task in a Build File

Dynamic Properties

A Task has 3 'scopes' for properties. You can access these properties by name from the build file or by calling the property(String) method.

Dynamic Methods

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


Field Summary
static java.lang.String AUTOSKIP_PROPERTY_PREFIX
           
static java.lang.String TASK_ACTION
           
static java.lang.String TASK_DEPENDS_ON
           
static java.lang.String TASK_DESCRIPTION
           
static java.lang.String TASK_NAME
           
static java.lang.String TASK_OVERWRITE
           
static java.lang.String TASK_TYPE
           
 
Method Summary
 Task captureStandardOutput(LogLevel level)
          Enables redirection of standard output during task execution to the logging system.
 Task configure(groovy.lang.Closure configureClosure)
          Applies the statements of the closure against this task object.
 Task deleteAllActions()
          Removes all the actions of this task.
 Task dependsOn(java.lang.Object... paths)
          Adds the given dependencies to this task.
 boolean dependsOnTaskDidWork()
          Checks if any of the tasks that this task depends on didWork.
 Task disableStandardOutputCapture()
          Disables redirection of standard output during task execution.
 Task doFirst(Action<? super Task> action)
          Adds the given TaskAction to the beginning of this task's action list.
 Task doFirst(groovy.lang.Closure action)
          Adds the given closure to the beginning of this task's action list.
 Task doLast(Action<? super Task> action)
          Adds the given TaskAction to the end of this task's action list.
 Task doLast(groovy.lang.Closure action)
          Adds the given closure to the end of this task's action list.
 java.util.List<Action<? super Task>> getActions()
          Returns the sequence of TaskAction objects which will be executed by this task, in the order of execution.
 AntBuilder getAnt()
          Returns the AntBuilder for this task.
 Convention getConvention()
          Returns the Convention object for this task.
 java.util.Set<java.lang.Object> getDependsOn()
          Returns the dependencies of this task.
 java.lang.String getDescription()
          Returns the description of a task.
 boolean getDidWork()
          Checks if the task actually did any work.
 boolean getEnabled()
          Returns if this task is enabled or not.
 boolean getExecuted()
          Returns true if this task has been executed.
 Logger getLogger()
          Returns the logger for this task.
 java.lang.String getName()
          Returns the name of this task.
 org.gradle.execution.OutputHandler getOutput()
          Returns a OutputHandler object providing information whether a task's output was created successfully and when it was last modified.
 java.lang.String getPath()
          Returns the path of the task, which is a fully qualified name for the task.
 Project getProject()
          Returns the Project which this task belongs to.
 TaskDependency getTaskDependencies()
          Returns a TaskDependency which contains all the tasks that this task depends on.
 boolean hasProperty(java.lang.String propertyName)
          Determines if this task has the given property.
 Task leftShift(groovy.lang.Closure action)
          Adds the given closure to the end of this task's action list.
 void onlyIf(groovy.lang.Closure onlyIfClosure)
          Execute the task only if the closure returns true.
 void onlyIf(Spec<? super Task> onlyIfSpec)
          Execute the task only if the spec is satisfied.
 java.lang.Object property(java.lang.String propertyName)
          Returns the value of the given property of this task.
 void setActions(java.util.List<Action<? super Task>> actions)
          Sets the sequence of TaskAction objects which will be executed by this task.
 void setDependsOn(java.lang.Iterable<?> dependsOnTasks)
          Sets the dependencies of this task.
 void setDescription(java.lang.String description)
          Adds a text to describe what the task does to the user of the build.
 void setEnabled(boolean enabled)
          Set the enabled state of a task.
 void setProperty(java.lang.String name, java.lang.Object value)
          Sets a property of this task.
 
Methods inherited from interface java.lang.Comparable
compareTo
 

Field Detail

TASK_NAME

static final java.lang.String TASK_NAME
See Also:
Constant Field Values

TASK_DESCRIPTION

static final java.lang.String TASK_DESCRIPTION
See Also:
Constant Field Values

TASK_TYPE

static final java.lang.String TASK_TYPE
See Also:
Constant Field Values

TASK_DEPENDS_ON

static final java.lang.String TASK_DEPENDS_ON
See Also:
Constant Field Values

TASK_OVERWRITE

static final java.lang.String TASK_OVERWRITE
See Also:
Constant Field Values

TASK_ACTION

static final java.lang.String TASK_ACTION
See Also:
Constant Field Values

AUTOSKIP_PROPERTY_PREFIX

static final java.lang.String AUTOSKIP_PROPERTY_PREFIX
See Also:
Constant Field Values
Method Detail

getName

java.lang.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

Project getProject()

Returns the Project which this task belongs to.

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

getActions

java.util.List<Action<? super Task>> getActions()

Returns the sequence of TaskAction 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(java.util.List<Action<? super Task>> actions)

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

Parameters:
actions - The actions.

getTaskDependencies

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

java.util.Set<java.lang.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(java.lang.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(java.lang.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.
Returns:
the task object this method is applied to

onlyIf

void onlyIf(groovy.lang.Closure onlyIfClosure)

Execute the task only if the closure returns true. The closure will be evaluated at the task execution time, not during configuration. The closure will be passed a single parameter, this task. The closure will be coerced to a Spec of type Task.

If the closure returns false, the task will not execute, but will log a message of 'SKIPPED as onlyIf is false'.

Typical usage:

myTask.onlyIf{ dependsOnTaskDidWork() }

Parameters:
onlyIfClosure - code to execute to determine if task should be run
See Also:
getDidWork()

onlyIf

void onlyIf(Spec<? super Task> onlyIfSpec)

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

If the Spec is not satisfied, the task will not execute, but will log a message of 'SKIPPED as onlyIf is false'.

Typical usage (from Java):

myTask.onlyIf(new Spec() {
    boolean isSatisfiedBy(Task task) {
       return task.dependsOnTaskDidWork();
    }
 });
 

Parameters:
onlyIfSpec - specifies if a task should be run
See Also:
getDidWork()

getDidWork

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, the Compile 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

getExecuted

boolean getExecuted()

Returns true if this task has been executed.

Returns:
true if this task has been executed already, false otherwise.

getPath

java.lang.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 TaskAction 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(groovy.lang.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.

doLast

Task doLast(Action<? super Task> action)

Adds the given TaskAction 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

Task doLast(groovy.lang.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

Task leftShift(groovy.lang.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

boolean getEnabled()

Returns if this task is enabled or not.

See Also:
setEnabled(boolean)

getOutput

org.gradle.execution.OutputHandler getOutput()
Returns a OutputHandler object providing information whether a task's output was created successfully and when it was last modified.


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(groovy.lang.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

AntBuilder getAnt()

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

Returns:
The AntBuilder

getLogger

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.

disableStandardOutputCapture

Task disableStandardOutputCapture()
Disables redirection of standard output during task execution. By default redirection is enabled.

Returns:
this
See Also:
captureStandardOutput(org.gradle.api.logging.LogLevel)

captureStandardOutput

Task captureStandardOutput(LogLevel level)
Enables redirection of standard output during task execution to the logging system. By default redirection is enabled and the task output is redirected to the QUIET level. System.err is always redirected to the ERROR level. An exception is thrown, if this method is called during the execution of the task For more fine-grained control on redirecting standard output see StandardOutputLogging.

Parameters:
level - The level standard out should be logged to.
Returns:
this
See Also:
disableStandardOutputCapture()

property

java.lang.Object property(java.lang.String propertyName)
                          throws groovy.lang.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 additional property with the given name, return the value of the property.
  3. If this task's convention object has a property with the given name, return the value of the property.
  4. If not found, throw MissingPropertyException

Parameters:
propertyName - The name of the property.
Returns:
The value of the property, possibly null.
Throws:
groovy.lang.MissingPropertyException - When the given property is unknown.

hasProperty

boolean hasProperty(java.lang.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(java.lang.String name,
                 java.lang.Object value)

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 additional properties.

If the property is not found in any of these locations, it is added to the project's additional properties.

Parameters:
name - The name of the property
value - The value of the property

getConvention

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

java.lang.String getDescription()
Returns the description of a task.

See Also:
setDescription(String)

setDescription

void setDescription(java.lang.String description)
Adds a text to describe what the task does to the user of the build. The description will be displayed when gradle -t is called.

Parameters:
description - The description of the task. Might be null.

dependsOnTaskDidWork

boolean dependsOnTaskDidWork()

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

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