Packages

t

scala.reflect

Manifest

trait Manifest[T] extends ClassManifest[T] with Equals

A Manifest[T] is an opaque descriptor for type T. Its supported use is to give access to the erasure of the type as a Class instance, as is necessary for the creation of native Arrays if the class is not known at compile time.

The type-relation operators <:< and =:= should be considered approximations only, as there are numerous aspects of type conformance which are not yet adequately represented in manifests.

Example usages:

def arr[T] = new Array[T](0)                          // does not compile
def arr[T](implicit m: Manifest[T]) = new Array[T](0) // compiles
def arr[T: Manifest] = new Array[T](0)                // shorthand for the preceding

// Methods manifest, classManifest, and optManifest are in [[scala.Predef]].
def isApproxSubType[T: Manifest, U: Manifest] = manifest[T] <:< manifest[U]
isApproxSubType[List[String], List[AnyRef]] // true
isApproxSubType[List[String], List[Int]]    // false

def methods[T: ClassManifest] = classManifest[T].erasure.getMethods
def retType[T: ClassManifest](name: String) =
  methods[T] find (_.getName == name) map (_.getGenericReturnType)

retType[Map[_, _]]("values")  // Some(scala.collection.Iterable)
Annotations
@implicitNotFound( msg = "No Manifest available for ${T}." )
Source
Manifest.scala
Linear Supertypes
ClassTag[T], Equals, ClassManifestDeprecatedApis[T], OptManifest[T], Serializable, java.io.Serializable, AnyRef, Any
Known Subclasses
AnyValManifest
Ordering
  1. Alphabetic
  2. By Inheritance
Inherited
  1. Manifest
  2. ClassTag
  3. Equals
  4. ClassManifestDeprecatedApis
  5. OptManifest
  6. Serializable
  7. Serializable
  8. AnyRef
  9. Any
Implicitly
  1. by any2stringadd
  2. by StringFormat
  3. by Ensuring
  4. by ArrowAssoc
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Visibility
  1. Public
  2. All

Abstract Value Members

  1. abstract def runtimeClass: Class[_]

    A class representing the type U to which T would be erased.

    A class representing the type U to which T would be erased. Note that there is no subtyping relationship between T and U.

    Definition Classes
    ClassTag

Concrete Value Members

  1. def arrayManifest: Manifest[Array[T]]
    Definition Classes
    Manifest → ClassManifestDeprecatedApis
  2. def canEqual(that: Any): Boolean

    A method that should be called from every well-designed equals method that is open to be overridden in a subclass.

    A method that should be called from every well-designed equals method that is open to be overridden in a subclass. See Programming in Scala, Chapter 28 for discussion and design.

    that

    the value being probed for possible equality

    returns

    true if this instance can possibly equal that, otherwise false

    Definition Classes
    Manifest → ClassTag → Equals → ClassManifestDeprecatedApis
  3. def equals(that: Any): Boolean

    Note: testing for erasure here is important, as it is many times faster than <:< and rules out most comparisons.

    Note: testing for erasure here is important, as it is many times faster than <:< and rules out most comparisons.

    Definition Classes
    Manifest → ClassTag → Equals → AnyRef → Any
  4. def hashCode(): Int

    The hashCode method for reference types.

    The hashCode method for reference types. See hashCode in scala.Any.

    returns

    the hash code value for this object.

    Definition Classes
    Manifest → ClassTag → AnyRef → Any
  5. def newArray(len: Int): Array[T]

    Produces a new array with element type T and length len

    Produces a new array with element type T and length len

    Definition Classes
    ClassTag → ClassManifestDeprecatedApis
  6. def toString(): String

    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.

    returns

    a String representation of the object.

    Definition Classes
    ClassTag → AnyRef → Any
  7. def typeArguments: List[Manifest[_]]
    Definition Classes
    Manifest → ClassManifestDeprecatedApis
  8. def unapply(x: Any): Option[T]

    A ClassTag[T] can serve as an extractor that matches only objects of type T.

    A ClassTag[T] can serve as an extractor that matches only objects of type T.

    The compiler tries to turn unchecked type tests in pattern matches into checked ones by wrapping a (_: T) type pattern as ct(_: T), where ct is the ClassTag[T] instance. Type tests necessary before calling other extractors are treated similarly. SomeExtractor(...) is turned into ct(SomeExtractor(...)) if T in SomeExtractor.unapply(x: T) is uncheckable, but we have an instance of ClassTag[T].

    Definition Classes
    ClassTag
  9. def wrap: ClassTag[Array[T]]

    Produces a ClassTag that knows how to instantiate an Array[Array[T]]

    Produces a ClassTag that knows how to instantiate an Array[Array[T]]

    Definition Classes
    ClassTag

Deprecated Value Members

  1. def <:<(that: ClassManifest[_]): Boolean

    Tests whether the type represented by this manifest is a subtype of the type represented by that manifest, subject to the limitations described in the header.

    Tests whether the type represented by this manifest is a subtype of the type represented by that manifest, subject to the limitations described in the header.

    Definition Classes
    ClassManifestDeprecatedApis
    Annotations
    @deprecated
    Deprecated

    (Since version 2.10.0) use scala.reflect.runtime.universe.TypeTag for subtype checking instead

  2. def >:>(that: ClassManifest[_]): Boolean

    Tests whether the type represented by this manifest is a supertype of the type represented by that manifest, subject to the limitations described in the header.

    Tests whether the type represented by this manifest is a supertype of the type represented by that manifest, subject to the limitations described in the header.

    Definition Classes
    ClassManifestDeprecatedApis
    Annotations
    @deprecated
    Deprecated

    (Since version 2.10.0) use scala.reflect.runtime.universe.TypeTag for subtype checking instead

  3. def erasure: Class[_]
    Definition Classes
    ClassManifestDeprecatedApis
    Annotations
    @deprecated
    Deprecated

    (Since version 2.10.0) use runtimeClass instead

  4. def newArray2(len: Int): Array[Array[T]]
    Definition Classes
    ClassManifestDeprecatedApis
    Annotations
    @deprecated
    Deprecated

    (Since version 2.10.0) use wrap.newArray instead

  5. def newArray3(len: Int): Array[Array[Array[T]]]
    Definition Classes
    ClassManifestDeprecatedApis
    Annotations
    @deprecated
    Deprecated

    (Since version 2.10.0) use wrap.wrap.newArray instead

  6. def newArray4(len: Int): Array[Array[Array[Array[T]]]]
    Definition Classes
    ClassManifestDeprecatedApis
    Annotations
    @deprecated
    Deprecated

    (Since version 2.10.0) use wrap.wrap.wrap.newArray instead

  7. def newArray5(len: Int): Array[Array[Array[Array[Array[T]]]]]
    Definition Classes
    ClassManifestDeprecatedApis
    Annotations
    @deprecated
    Deprecated

    (Since version 2.10.0) use wrap.wrap.wrap.wrap.newArray instead

  8. def newArrayBuilder(): ArrayBuilder[T]
    Definition Classes
    ClassManifestDeprecatedApis
    Annotations
    @deprecated
    Deprecated

    (Since version 2.10.0) use ArrayBuilder.make(this) instead

  9. def newWrappedArray(len: Int): WrappedArray[T]
    Definition Classes
    ClassManifestDeprecatedApis
    Annotations
    @deprecated
    Deprecated

    (Since version 2.10.0) create WrappedArray directly instead