org.gradle.api.plugins

Interface ExtraPropertiesExtension

public interface ExtraPropertiesExtension

Additional, ad-hoc, properties for Gradle domain objects.

Extra properties extensions allow new properties to be added to existing domain objects. They act like maps, allowing the storage of arbitrary key/value pairs. All ExtensionAware Gradle domain objects intrinsically have an extension named “"ext"” of this type.

An important feature of extra properties extensions is that all of its properties are exposed for reading and writing via the ExtensionAware object that owns the extension.

 project.ext.set("myProp", "myValue")
 assert project.myProp == "myValue"

 project.myProp = "anotherValue"
 assert project.myProp == "anotherValue"
 assert project.ext.get("myProp") == "anotherValue"
 

Extra properties extension objects support Groovy property syntax. That is, a property can be read via extension.«name» and set via extension.«name» = "value". Wherever possible, the Groovy property syntax should be preferred over the get(String) and set(String, Object) methods.

 project.ext {
   myprop = "a"
 }
 assert project.myprop == "a"
 assert project.ext.myprop == "a"

 project.myprop = "b"
 assert project.myprop == "b"
 assert project.ext.myprop == "b"
 

You can also use the Groovy accessor syntax to get and set properties on an extra properties extension.

 project.ext["otherProp"] = "a"
 assert project.otherProp == "a"
 assert project.ext["otherProp"] == "a"
 

The exception that is thrown when an attempt is made to get the value of a property that does not exist is different depending on whether the Groovy syntax is used or not. If Groovy property syntax is used, the Groovy MissingPropertyException will be thrown. When the get(String) method is used, an ExtraPropertiesExtension.UnknownPropertyException will be thrown.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	ExtraPropertiesExtension.UnknownPropertyException The exception that will be thrown when an attempt is made to read a property that is not set.

Field Summary

Fields

Modifier and Type	Field and Description
static String	EXTENSION_NAME The name of this extension in all ExtensionContainers, "ext".

Method Summary

Methods

Modifier and Type	Method and Description
Object	get(String name) Returns the value for the registered property with the given name.
Map<String,Object>	getProperties() Returns all of the registered properties and their current values as a map.
boolean	has(String name) Returns whether or not the extension has a property registered via the given name.
void	set(String name, Object value) Updates the value for, or creates, the registered property with the given name to the given value.

Field Detail

EXTENSION_NAME

static final String EXTENSION_NAME

The name of this extension in all ExtensionContainers, "ext".

See Also:

Constant Field Values

Method Detail

has

boolean has(String name)

Returns whether or not the extension has a property registered via the given name.

 assert project.ext.has("foo") == false
 assert project.hasProperty("foo") == false

 project.ext.foo = "bar"

 assert project.ext.has("foo")
 assert project.hasProperty("foo")
 

Parameters:

name - The name of the property to check for

Returns:

true if a property has been registered with this name, otherwise false.

get

Object get(String name)
           throws ExtraPropertiesExtension.UnknownPropertyException

Returns the value for the registered property with the given name. When using an extra properties extension from Groovy, you can also get properties via Groovy's property syntax. All of the following lines of code are equivalent.

 project.ext { foo = "bar" }

 assert project.ext.get("foo") == "bar"
 assert project.ext.foo == "bar"
 assert project.ext["foo"] == "bar"

 assert project.foo == "bar"
 assert project["foo"] == "bar"
 

When using the first form, an ExtraPropertiesExtension.UnknownPropertyException exception will be thrown if the extension does not have a property called “foo”. When using the second forms (i.e. Groovy notation), Groovy's MissingPropertyException will be thrown instead.

Parameters:

name - The name of the property to get the value of

Returns:

The value for the property with the given name.

Throws:

ExtraPropertiesExtension.UnknownPropertyException - if there is no property registered with the given name

set

void set(String name,
       Object value)

Updates the value for, or creates, the registered property with the given name to the given value. When using an extra properties extension from Groovy, you can also set properties via Groovy's property syntax. All of the following lines of code are equivalent.

 project.ext.set("foo", "bar")
 project.ext.foo = "bar"
 project.ext["foo"] = "bar"

 // Once the property has been created via the extension, it can be changed by the owner.
 project.foo = "bar"
 project["foo"] = "bar"
 

Parameters:

name - The name of the property to update the value of or create

value - The value to set for the property

getProperties

Map<String,Object> getProperties()

Returns all of the registered properties and their current values as a map. The returned map is detached from the extension. That is, any changes made to the map do not change the extension from which it originated.

 project.version = "1.0"

 assert project.hasProperty("version")
 assert project.ext.properties.containsKey("version") == false

 project.ext.foo = "bar"

 assert project.ext.properties.containsKey("foo")
 assert project.ext.properties.foo == project.ext.foo

 assert project.ext.properties.every { key, value -> project.properties[key] == value }
 

Returns:

All of the registered properties and their current values as a map.