Size

Supertrait for Size typeclasses.

Trait Size is a typeclass trait for objects that can be queried for size. Objects of type T for which an implicit Size[T] is available can be used with the should have size syntax. In other words, this trait enables you to use the size checking syntax with arbitrary objects. As an example, the following Bridge class:

scala> import org.scalatest._
import org.scalatest._

scala> import enablers.Size
import enablers.Size

scala> import Matchers._
import Matchers._

scala> case class Bridge(span: Int)
defined class Bridge

Out of the box you can't use the should have size syntax with Bridge, because ScalaTest doesn't know that a bridge's span means its size:

scala> val bridge = new Bridge(2000)
bridge: Bridge = Bridge(2000)

scala> bridge should have size 2000
<console>:34: error: could not find implicit value for
    parameter sz: org.scalatest.enablers.Size[Bridge]
      bridge should have size 2000
                         ^

You can teach this to ScalaTest, however, by defining an implicit Size[Bridge].

scala> implicit val sizeOfBridge: Size[Bridge] =
     |   new Size[Bridge] {
     |     def sizeOf(b: Bridge): Long = b.span
     |   }
sizeOfBridge: org.scalatest.enablers.Size[Bridge] = $anon$1@3fa27a4a

With the implicit Size[Bridge] in scope, you can now use ScalaTest's should have size syntax with Bridge instances:

scala> bridge should have size 2000
res4: org.scalatest.Assertion = Succeeded

scala> bridge should have size 2001
org.scalatest.exceptions.TestFailedException: Bridge(2000) had size 2000 instead of expected size 2001
  at org.scalatest.MatchersHelper$.newTestFailedException(MatchersHelper.scala:148)
  at org.scalatest.MatchersHelper$.indicateFailure(MatchersHelper.scala:366)
  at org.scalatest.Matchers$ResultOfHaveWordForExtent.size(Matchers.scala:2720)
  ... 43 elided

Source: Size.scala

Linear Supertypes

AnyRef, Any

Abstract Value Members

abstract def sizeOf(obj: T): Long

Returns the size of the passed object.
Returns the size of the passed object.
obj
the object whose size to return
returns
the size of the passed object

Concrete Value Members

final def !=(arg0: AnyRef): Boolean

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

Definition Classes
Any
final def ##(): Int

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

Definition Classes
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final def ==(arg0: Any): Boolean

Definition Classes
Any
final def asInstanceOf[T0]: T0

Definition Classes
Any
def clone(): AnyRef

Attributes
protected[java.lang]
Definition Classes
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Annotations
@throws( ... )
final def eq(arg0: AnyRef): Boolean

Definition Classes
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def equals(arg0: Any): Boolean

Definition Classes
AnyRef → Any
def finalize(): Unit

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
@throws( classOf[java.lang.Throwable] )
final def getClass(): Class[_]

Definition Classes
AnyRef → Any
def hashCode(): Int

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

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

Definition Classes
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final def notify(): Unit

Definition Classes
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final def notifyAll(): Unit

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

Definition Classes
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def toString(): String

Definition Classes
AnyRef → Any
final def wait(): Unit

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

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

Definition Classes
AnyRef
Annotations
@throws( ... )

trait Size[T] extends AnyRef

Abstract Value Members

abstract def sizeOf(obj: T): Long

Concrete Value Members

final def !=(arg0: AnyRef): Boolean

final def !=(arg0: Any): Boolean

final def ##(): Int

final def ==(arg0: AnyRef): Boolean

final def ==(arg0: Any): Boolean

final def asInstanceOf[T0]: T0

def clone(): AnyRef

final def eq(arg0: AnyRef): Boolean

def equals(arg0: Any): Boolean

def finalize(): Unit

final def getClass(): Class[_]

def hashCode(): Int

final def isInstanceOf[T0]: Boolean

final def ne(arg0: AnyRef): Boolean

final def notify(): Unit

final def notifyAll(): Unit

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

def toString(): String

final def wait(): Unit

final def wait(arg0: Long, arg1: Int): Unit

final def wait(arg0: Long): Unit

Inherited from AnyRef

Inherited from Any

Ungrouped