Annotations
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package api
Information about an annotation.
The API of Annotation instances.
The API of Annotation instances.
The main source of information about annotations is the scala.reflect.api.Annotations page.
An extractor class to create and pattern match with syntax Annotation(tpe, scalaArgs, javaArgs).
An extractor class to create and pattern match with syntax Annotation(tpe, scalaArgs, javaArgs).
Here, tpe is the annotation type, scalaArgs the payload of Scala annotations, and javaArgs the payload of Java annotations.
An array argument to a Java annotation as in @Target(value={TYPE,FIELD,METHOD,PARAMETER})
An array argument to a Java annotation as in @Target(value={TYPE,FIELD,METHOD,PARAMETER})
(Since version 2.11.0) Use Annotation.tree to inspect annotation arguments
API of ArrayArgument instances.
API of ArrayArgument instances.
The main source of information about annotations is the scala.reflect.api.Annotations page.
(Since version 2.11.0) Use Annotation.tree to inspect annotation arguments
An extractor class to create and pattern match with syntax ArrayArgument(args)
where args is the argument array.
An extractor class to create and pattern match with syntax ArrayArgument(args)
where args is the argument array.
(Since version 2.11.0) Use Annotation.tree to inspect annotation arguments
A Java annotation argument
A Java annotation argument
(Since version 2.11.0) Use Annotation.tree to inspect annotation arguments
Has no special methods.
Has no special methods. Is here to provides erased identity for CompoundType.
(Since version 2.11.0) Use Annotation.tree to inspect annotation arguments
A literal argument to a Java annotation as "Use X instead" in @Deprecated("Use X instead")
A literal argument to a Java annotation as "Use X instead" in @Deprecated("Use X instead")
(Since version 2.11.0) Use Annotation.tree to inspect annotation arguments
The API of LiteralArgument instances.
The API of LiteralArgument instances.
The main source of information about annotations is the scala.reflect.api.Annotations page.
(Since version 2.11.0) Use Annotation.tree to inspect annotation arguments
An extractor class to create and pattern match with syntax LiteralArgument(value)
where value is the constant argument.
An extractor class to create and pattern match with syntax LiteralArgument(value)
where value is the constant argument.
(Since version 2.11.0) Use Annotation.tree to inspect annotation arguments
A nested annotation argument to a Java annotation as @Nested in @Outer(@Nested).
A nested annotation argument to a Java annotation as @Nested in @Outer(@Nested).
(Since version 2.11.0) Use Annotation.tree to inspect annotation arguments
API of NestedArgument instances.
API of NestedArgument instances.
The main source of information about annotations is the scala.reflect.api.Annotations page.
(Since version 2.11.0) Use Annotation.tree to inspect annotation arguments
An extractor class to create and pattern match with syntax NestedArgument(annotation)
where annotation is the nested annotation.
An extractor class to create and pattern match with syntax NestedArgument(annotation)
where annotation is the nested annotation.
(Since version 2.11.0) Use Annotation.tree to inspect annotation arguments
The constructor/extractor for Annotation instances.
The constructor/extractor for ArrayArgument instances.
The constructor/extractor for ArrayArgument instances.
(Since version 2.11.0) Use Annotation.tree to inspect annotation arguments
The constructor/extractor for LiteralArgument instances.
The constructor/extractor for LiteralArgument instances.
(Since version 2.11.0) Use Annotation.tree to inspect annotation arguments
The constructor/extractor for NestedArgument instances.
The constructor/extractor for NestedArgument instances.
(Since version 2.11.0) Use Annotation.tree to inspect annotation arguments
Test two objects for inequality.
Test two objects for inequality.
true if !(this == that), false otherwise.
Equivalent to x.hashCode except for boxed numeric types and null.
Equivalent to x.hashCode except for boxed numeric types and null.
For numerics, it returns a hash value which is consistent
with value equality: if two value type instances compare
as true, then ## will produce the same hash value for each
of them.
For null returns a hashcode where null.hashCode throws a
NullPointerException.
a hash value consistent with ==
The expression x == that is equivalent to if (x eq null) that eq null else x.equals(that).
The expression x == that is equivalent to if (x eq null) that eq null else x.equals(that).
true if the receiver object is equivalent to the argument; false otherwise.
Cast the receiver object to be of type T0.
Cast the receiver object to be of type T0.
Note that the success of a cast at runtime is modulo Scala's erasure semantics.
Therefore the expression 1.asInstanceOf[String] will throw a ClassCastException at
runtime, while the expression List(1).asInstanceOf[List[String]] will not.
In the latter example, because the type argument is erased as part of compilation it is
not possible to check whether the contents of the list are of the requested type.
the receiver object.
ClassCastException if the receiver object is not an instance of the erasure of type T0.
Create a copy of the receiver object.
Create a copy of the receiver object.
The default implementation of the clone method is platform dependent.
a copy of the receiver object.
not specified by SLS as a member of AnyRef
Tests whether the argument (that) is a reference to the receiver object (this).
Tests whether the argument (that) is a reference to the receiver object (this).
The eq method implements an equivalence relation on
non-null instances of AnyRef, and has three additional properties:
x and y of type AnyRef, multiple invocations of
x.eq(y) consistently returns true or consistently returns false.x of type AnyRef, x.eq(null) and null.eq(x) returns false.null.eq(null) returns true. When overriding the equals or hashCode methods, it is important to ensure that their behavior is
consistent with reference equality. Therefore, if two objects are references to each other (o1 eq o2), they
should be equal to each other (o1 == o2) and they should hash to the same value (o1.hashCode == o2.hashCode).
true if the argument is a reference to the receiver object; false otherwise.
The equality method for reference types.
Called by the garbage collector on the receiver object when there are no more references to the object.
Called by the garbage collector on the receiver object when there are no more references to the object.
The details of when and if the finalize method is invoked, as
well as the interaction between finalize and non-local returns
and exceptions, are all platform dependent.
not specified by SLS as a member of AnyRef
A representation that corresponds to the dynamic class of the receiver object.
A representation that corresponds to the dynamic class of the receiver object.
The nature of the representation is platform dependent.
a representation that corresponds to the dynamic class of the receiver object.
not specified by SLS as a member of AnyRef
The hashCode method for reference types.
Test whether the dynamic type of the receiver object is T0.
Test whether the dynamic type of the receiver object is T0.
Note that the result of the test is modulo Scala's erasure semantics.
Therefore the expression 1.isInstanceOf[String] will return false, while the
expression List(1).isInstanceOf[List[String]] will return true.
In the latter example, because the type argument is erased as part of compilation it is
not possible to check whether the contents of the list are of the specified type.
true if the receiver object is an instance of erasure of type T0; false otherwise.
Equivalent to !(this eq that).
Equivalent to !(this eq that).
true if the argument is not a reference to the receiver object; false otherwise.
Wakes up a single thread that is waiting on the receiver object's monitor.
Wakes up a single thread that is waiting on the receiver object's monitor.
not specified by SLS as a member of AnyRef
Wakes up all threads that are waiting on the receiver object's monitor.
Wakes up all threads that are waiting on the receiver object's monitor.
not specified by SLS as a member of AnyRef
Creates a String representation of this object.
Creates a String representation of this object. The default representation is platform dependent. On the java platform it is the concatenation of the class name, "@", and the object's hashcode in hexadecimal.
a String representation of the object.
The methods available for each reflection entity, without the implementation. Since the reflection entities are later overridden by runtime reflection and macros, their API counterparts guarantee a minimum set of methods that are implemented.
Extractors provide the machinery necessary to allow pattern matching and construction of reflection entities that is similar to case classes, although the entities are only abstract types that are later overridden.
EXPERIMENTAL
This trait provides annotation support for the reflection API.
In Scala, annotations belong to one of the two categories:
When a Scala annotation that inherits from scala.annotation.StaticAnnotation or scala.annotation.ClassfileAnnotation is compiled, it is stored as special attributes in the corresponding classfile, and not as a Java annotation. Note that subclassing just scala.annotation.Annotation is not enough to have the corresponding metadata persisted for runtime reflection.
Both Java and Scala annotations are represented as typed trees carrying constructor invocations corresponding to the annotation. For instance, the annotation in
@ann(1, 2) class Cis represented asq"@new ann(1, 2)".Unlike Java reflection, Scala reflection does not support evaluation of constructor invocations stored in annotations into underlying objects. For instance it's impossible to go from
@ann(1, 2) class Ctoann(1, 2), so one has to analyze trees representing annotation arguments to manually extract corresponding values. Towards that end, arguments of an annotation can be obtained viaannotation.tree.children.tail.For more information about
Annotations, see the Reflection Guide: Annotations, Names, Scopes, and More