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
Known Subclasses
Type Hierarchy Learn more about scaladoc diagrams
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 StringAdd
  2. by StringFormat
  3. by Ensuring
  4. by ArrowAssoc
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. final def !=(arg0: AnyRef): Boolean

    Definition Classes
    AnyRef
  2. final def !=(arg0: Any): Boolean

    Definition Classes
    Any
  3. final def ##(): Int

    Definition Classes
    AnyRef → Any
  4. def +(other: String): String

    Implicit information
    This member is added by an implicit conversion from Manifest[T] to StringAdd[Manifest[T]] performed by method StringAdd in scala.Predef.
    Definition Classes
    StringAdd
  5. def ->[B](y: B): (Manifest[T], B)

    Implicit information
    This member is added by an implicit conversion from Manifest[T] to ArrowAssoc[Manifest[T]] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @inline()
  6. final def ==(arg0: AnyRef): Boolean

    Definition Classes
    AnyRef
  7. final def ==(arg0: Any): Boolean

    Definition Classes
    Any
  8. def argString: String

    Attributes
    protected
    Definition Classes
    ClassManifestDeprecatedApis
  9. def arrayClass[T](tp: Class[_]): Class[Array[T]]

    Attributes
    protected
    Definition Classes
    ClassManifestDeprecatedApis
  10. def arrayManifest: Manifest[Array[T]]

    Definition Classes
    ManifestClassManifestDeprecatedApis
  11. final def asInstanceOf[T0]: T0

    Definition Classes
    Any
  12. 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
    ManifestClassTagEqualsClassManifestDeprecatedApis
  13. def clone(): AnyRef

    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  14. def ensuring(cond: (Manifest[T]) ⇒ Boolean, msg: ⇒ Any): Manifest[T]

    Implicit information
    This member is added by an implicit conversion from Manifest[T] to Ensuring[Manifest[T]] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  15. def ensuring(cond: (Manifest[T]) ⇒ Boolean): Manifest[T]

    Implicit information
    This member is added by an implicit conversion from Manifest[T] to Ensuring[Manifest[T]] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  16. def ensuring(cond: Boolean, msg: ⇒ Any): Manifest[T]

    Implicit information
    This member is added by an implicit conversion from Manifest[T] to Ensuring[Manifest[T]] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  17. def ensuring(cond: Boolean): Manifest[T]

    Implicit information
    This member is added by an implicit conversion from Manifest[T] to Ensuring[Manifest[T]] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  18. final def eq(arg0: AnyRef): Boolean

    Definition Classes
    AnyRef
  19. 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
    ManifestClassTagEquals → AnyRef → Any
  20. def finalize(): Unit

    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( classOf[java.lang.Throwable] )
  21. def formatted(fmtstr: String): String

    Returns string formatted according to given format string.

    Returns string formatted according to given format string. Format strings are as for String.format (@see java.lang.String.format).

    Implicit information
    This member is added by an implicit conversion from Manifest[T] to StringFormat[Manifest[T]] performed by method StringFormat in scala.Predef.
    Definition Classes
    StringFormat
    Annotations
    @inline()
  22. final def getClass(): Class[_]

    Definition Classes
    AnyRef → Any
  23. def hashCode(): Int

    Definition Classes
    ManifestClassTag → AnyRef → Any
  24. final def isInstanceOf[T0]: Boolean

    Definition Classes
    Any
  25. final def ne(arg0: AnyRef): Boolean

    Definition Classes
    AnyRef
  26. 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
    ClassTagClassManifestDeprecatedApis
  27. final def notify(): Unit

    Definition Classes
    AnyRef
  28. final def notifyAll(): Unit

    Definition Classes
    AnyRef
  29. final def synchronized[T0](arg0: ⇒ T0): T0

    Definition Classes
    AnyRef
  30. def toString(): String

    Definition Classes
    ClassTag → AnyRef → Any
  31. def typeArguments: List[Manifest[_]]

    Definition Classes
    ManifestClassManifestDeprecatedApis
  32. def unapply(x: Unit): Option[T]

    Definition Classes
    ClassTag
  33. def unapply(x: Boolean): Option[T]

    Definition Classes
    ClassTag
  34. def unapply(x: Double): Option[T]

    Definition Classes
    ClassTag
  35. def unapply(x: Float): Option[T]

    Definition Classes
    ClassTag
  36. def unapply(x: Long): Option[T]

    Definition Classes
    ClassTag
  37. def unapply(x: Int): Option[T]

    Definition Classes
    ClassTag
  38. def unapply(x: Char): Option[T]

    Definition Classes
    ClassTag
  39. def unapply(x: Short): Option[T]

    Definition Classes
    ClassTag
  40. def unapply(x: Byte): Option[T]

    Definition Classes
    ClassTag
  41. 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
  42. final def wait(): Unit

    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  43. final def wait(arg0: Long, arg1: Int): Unit

    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  44. final def wait(arg0: Long): Unit

    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  45. 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
  46. def [B](y: B): (Manifest[T], B)

    Implicit information
    This member is added by an implicit conversion from Manifest[T] to ArrowAssoc[Manifest[T]] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc

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

Inherited from ClassTag[T]

Inherited from Equals

Inherited from ClassManifestDeprecatedApis[T]

Inherited from OptManifest[T]

Inherited from Serializable

Inherited from java.io.Serializable

Inherited from AnyRef

Inherited from Any

Inherited by implicit conversion StringAdd from Manifest[T] to StringAdd[Manifest[T]]

Inherited by implicit conversion StringFormat from Manifest[T] to StringFormat[Manifest[T]]

Inherited by implicit conversion Ensuring from Manifest[T] to Ensuring[Manifest[T]]

Inherited by implicit conversion ArrowAssoc from Manifest[T] to ArrowAssoc[Manifest[T]]

Ungrouped