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 any2stringadd
  2. by any2stringfmt
  3. by any2ArrowAssoc
  4. by any2Ensuring
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

    Test two objects for inequality.

    Test two objects for inequality.

    returns

    true if !(this == that), false otherwise.

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

    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.

    returns

    a hash value consistent with ==

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

    Implicit information
    This member is added by an implicit conversion from Manifest[T] to StringAdd performed by method any2stringadd 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 any2ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @inline()
  6. final def ==(arg0: AnyRef): Boolean

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

    Test two objects for equality.

    Test two objects for equality. The expression x == that is equivalent to if (x eq null) that eq null else x.equals(that).

    returns

    true if the receiver object is equivalent to the argument; false otherwise.

    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

    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.

    returns

    the receiver object.

    Definition Classes
    Any
    Exceptions thrown
    ClassCastException

    if the receiver object is not an instance of the erasure of type T0.

  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

    Create a copy of the receiver object.

    Create a copy of the receiver object.

    The default implementation of the clone method is platform dependent.

    returns

    a copy of the receiver object.

    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @throws()
    Note

    not specified by SLS as a member of AnyRef

  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 any2Ensuring 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 any2Ensuring 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 any2Ensuring 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 any2Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  18. final def eq(arg0: AnyRef): Boolean

    Tests whether the argument (arg0) is a reference to the receiver object (this).

    Tests whether the argument (arg0) 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:

    • It is consistent: for any non-null instances x and y of type AnyRef, multiple invocations of x.eq(y) consistently returns true or consistently returns false.
    • For any non-null instance 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).

    returns

    true if the argument is a reference to the receiver object; false otherwise.

    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.

    that

    the object to compare against this object for equality.

    returns

    true if the receiver object is equivalent to the argument; false otherwise.

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

    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.

    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @throws()
    Note

    not specified by SLS as a member of AnyRef

  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 performed by method any2stringfmt in scala.Predef.
    Definition Classes
    StringFormat
    Annotations
    @inline()
  22. final def getClass(): Class[_]

    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.

    returns

    a representation that corresponds to the dynamic class of the receiver object.

    Definition Classes
    AnyRef → Any
    Note

    not specified by SLS as a member of AnyRef

  23. 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
    ManifestClassTag → AnyRef → Any
  24. final def isInstanceOf[T0]: Boolean

    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.

    returns

    true if the receiver object is an instance of erasure of type T0; false otherwise.

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

    Equivalent to !(this eq that).

    Equivalent to !(this eq that).

    returns

    true if the argument is not a reference to the receiver object; false otherwise.

    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

    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.

    Definition Classes
    AnyRef
    Note

    not specified by SLS as a member of AnyRef

  28. final def notifyAll(): Unit

    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.

    Definition Classes
    AnyRef
    Note

    not specified by SLS as a member of AnyRef

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

    Definition Classes
    AnyRef
  30. 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
  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 any2ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc

Shadowed Implict Value Members

  1. val self: Any

    Implicit information
    This member is added by an implicit conversion from Manifest[T] to StringAdd performed by method any2stringadd in scala.Predef.
    Shadowing
    This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
    To access this member you can use a type ascription:
    (manifest: StringAdd).self
    Definition Classes
    StringAdd
  2. val self: Any

    Implicit information
    This member is added by an implicit conversion from Manifest[T] to StringFormat performed by method any2stringfmt in scala.Predef.
    Shadowing
    This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
    To access this member you can use a type ascription:
    (manifest: StringFormat).self
    Definition Classes
    StringFormat

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

  10. def x: Manifest[T]

    Implicit information
    This member is added by an implicit conversion from Manifest[T] to ArrowAssoc[Manifest[T]] performed by method any2ArrowAssoc in scala.Predef.
    Shadowing
    This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
    To access this member you can use a type ascription:
    (manifest: ArrowAssoc[Manifest[T]]).x
    Definition Classes
    ArrowAssoc
    Annotations
    @deprecated
    Deprecated

    (Since version 2.10.0) Use leftOfArrow instead

  11. def x: Manifest[T]

    Implicit information
    This member is added by an implicit conversion from Manifest[T] to Ensuring[Manifest[T]] performed by method any2Ensuring in scala.Predef.
    Shadowing
    This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
    To access this member you can use a type ascription:
    (manifest: Ensuring[Manifest[T]]).x
    Definition Classes
    Ensuring
    Annotations
    @deprecated
    Deprecated

    (Since version 2.10.0) Use resultOfEnsuring 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 any2stringadd from Manifest[T] to StringAdd

Inherited by implicit conversion any2stringfmt from Manifest[T] to StringFormat

Inherited by implicit conversion any2ArrowAssoc from Manifest[T] to ArrowAssoc[Manifest[T]]

Inherited by implicit conversion any2Ensuring from Manifest[T] to Ensuring[Manifest[T]]

Ungrouped