AClassTag[T] stores the erased class of a given typeT, accessible via theruntimeClass field. This is particularly useful for instantiatingArrays whose element types are unknown at compile time.
ClassTags are a weaker special case ofscala.reflect.api.TypeTags.TypeTags, in that they wrap only the runtime class of a given type, whereas aTypeTag contains all static type information. That is,ClassTags are constructed from knowing only the top-level class of a type, without necessarily knowing all of its argument types. This runtime information is enough for runtimeArray creation.
For example:
scala> def mkArray[T : ClassTag](elems: T*) = Array[T](elems: _*)mkArray: [T](elems: T*)(implicit evidence$1: scala.reflect.ClassTag[T])Array[T]scala> mkArray(42, 13)res0: Array[Int] = Array(42, 13)scala> mkArray("Japan","Brazil","Germany")res1: Array[String] = Array(Japan, Brazil, Germany)Seescala.reflect.api.TypeTags for more examples, or theReflection Guide: TypeTags for more details.
Attributes
- Companion
- object
- Source
- ClassTag.scala
- Graph
- Supertypes
- traitEqualstraitClassManifestDeprecatedApis[T]traitOptManifest[T]traitSerializableclassObjecttraitMatchableclassAnyShow all
- Known subtypes
- traitManifest[T]classAnyValManifest[T]
Members list
Value members
Abstract methods
A class representing the typeU to whichT would be erased.
A class representing the typeU to whichT would be erased. Note that there is no subtyping relationship betweenT andU.
Attributes
- Source
- ClassTag.scala
Concrete methods
Checks whether this instance can possibly equalthat.
Checks whether this instance can possibly equalthat.
A method that should be called from every well-designed equals method that is open to be overridden in a subclass. SeeProgramming in Scala, Chapter 28 for discussion and design.
Value parameters
- that
the value being probed for possible equality
Attributes
- Returns
true if this instance can possibly equal
that, otherwise false- Definition Classes
- Source
- ClassTag.scala
Checks whether this instance is equal tothat.
Checks whether this instance is equal tothat. This universal equality method is defined inAnyRef.
Attributes
- Definition Classes
- Source
- ClassTag.scala
Calculates a hash code value for the object.
Calculates a hash code value for the object.
The default hashing algorithm is platform dependent.
Note that it is allowed for two objects to have identical hash codes (o1.hashCode.equals(o2.hashCode)) yet not be equal (o1.equals(o2) returnsfalse). A degenerate implementation could always return0. However, it is required that if two objects are equal (o1.equals(o2) returnstrue) that they have identical hash codes (o1.hashCode.equals(o2.hashCode)). Therefore, when overriding this method, be sure to verify that the behavior is consistent with theequals method.
Attributes
- Returns
the hash code value for this object.
- Definition Classes
- Source
- ClassTag.scala
Produces a new array with element typeT and lengthlen
Returns a string representation of the object.
Returns a string representation of the object.
The default representation is platform dependent.
Attributes
- Returns
a string representation of the object.
- Definition Classes
- Source
- ClassTag.scala
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 asct(_: T), wherect is theClassTag[T] instance. Type tests necessary before calling other extractors are treated similarly.SomeExtractor(...) is turned intoct(SomeExtractor(...)) ifT inSomeExtractor.unapply(x: T) is uncheckable, but we have an instance ofClassTag[T].
Attributes
- Source
- ClassTag.scala
Produces aClassTag that knows how to instantiate anArray[Array[T]]
Inherited methods
Attributes
- Inherited from:
- ClassManifestDeprecatedApis
- Source
- ClassManifestDeprecatedApis.scala
Attributes
- Inherited from:
- ClassManifestDeprecatedApis
- Source
- ClassManifestDeprecatedApis.scala
Deprecated and Inherited methods
Tests whether the type represented by this manifest is a subtype of the type represented bythat manifest, subject to the limitations described in the header.
Tests whether the type represented by this manifest is a subtype of the type represented bythat manifest, subject to the limitations described in the header.
Attributes
- Deprecated
[Since version 2.10.0]use scala.reflect.runtime.universe.TypeTag for subtype checking instead- Inherited from:
- ClassManifestDeprecatedApis
- Source
- ClassManifestDeprecatedApis.scala
Tests whether the type represented by this manifest is a supertype of the type represented bythat manifest, subject to the limitations described in the header.
Tests whether the type represented by this manifest is a supertype of the type represented bythat manifest, subject to the limitations described in the header.
Attributes
- Deprecated
[Since version 2.10.0]use scala.reflect.runtime.universe.TypeTag for subtype checking instead- Inherited from:
- ClassManifestDeprecatedApis
- Source
- ClassManifestDeprecatedApis.scala
Attributes
- Deprecated
[Since version 2.10.0]use wrap instead- Inherited from:
- ClassManifestDeprecatedApis
- Source
- ClassManifestDeprecatedApis.scala
Attributes
- Deprecated
[Since version 2.10.0]use runtimeClass instead- Inherited from:
- ClassManifestDeprecatedApis
- Source
- ClassManifestDeprecatedApis.scala
Attributes
- Deprecated
[Since version 2.10.0]use wrap.newArray instead- Inherited from:
- ClassManifestDeprecatedApis
- Source
- ClassManifestDeprecatedApis.scala
Attributes
- Deprecated
[Since version 2.10.0]use wrap.wrap.newArray instead- Inherited from:
- ClassManifestDeprecatedApis
- Source
- ClassManifestDeprecatedApis.scala
Attributes
- Deprecated
[Since version 2.10.0]use wrap.wrap.wrap.newArray instead- Inherited from:
- ClassManifestDeprecatedApis
- Source
- ClassManifestDeprecatedApis.scala
Attributes
- Deprecated
[Since version 2.10.0]use wrap.wrap.wrap.wrap.newArray instead- Inherited from:
- ClassManifestDeprecatedApis
- Source
- ClassManifestDeprecatedApis.scala
Attributes
- Deprecated
[Since version 2.10.0]use ArrayBuilder.make(this) instead- Inherited from:
- ClassManifestDeprecatedApis
- Source
- ClassManifestDeprecatedApis.scala
Attributes
- Deprecated
[Since version 2.10.0]create WrappedArray directly instead- Inherited from:
- ClassManifestDeprecatedApis
- Source
- ClassManifestDeprecatedApis.scala
Attributes
- Deprecated
[Since version 2.10.0]use scala.reflect.runtime.universe.TypeTag to capture type structure instead- Inherited from:
- ClassManifestDeprecatedApis
- Source
- ClassManifestDeprecatedApis.scala