Length

Supertrait for Length typeclasses.

Trait Length is a typeclass trait for objects that can be queried for length. Objects of type T for which an implicit Length[T] is available can be used with the should have length syntax. In other words, this trait enables you to use the length checking syntax with arbitrary objects. As an example, consider java.net.DatagramPacket, which has a getLength method. By default, this can't be used with ScalaTest's have length syntax.

scala> import java.net.DatagramPacket
import java.net.DatagramPacket

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

scala> val dp = new DatagramPacket(Array(0x0, 0x1, 0x2, 0x3), 4)
dp: java.net.DatagramPacket = java.net.DatagramPacket@54906181

scala> dp.getLength
res0: Int = 4

scala> dp should have length 4
:13: error: could not find implicit value for parameter ev: org.scalatest.matchers.ShouldMatchers.Extent[java.net.DatagramPacket]
         dp should have length 4
            ^

scala> implicit val lengthOfDatagramPacket =
    |   new Length[DatagramPacket] {
    |     def lengthOf(dp: DatagramPacket): Long = dp.getLength
    |   }
lengthOfDatagramPacket: java.lang.Object with org.scalatest.matchers.ShouldMatchers.Length[java.net.DatagramPacket] = $anon$1@550c6b37

scala> dp should have length 4

scala> dp should have length 3
org.scalatest.exceptions.TestFailedException:  java.net.DatagramPacket@54906181 had length 4, not length 3

Source: Length.scala

Linear Supertypes

AnyRef, Any

Abstract Value Members

abstract def lengthOf(obj: T): Long

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

Concrete Value Members

final def !=(arg0: AnyRef): Boolean

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

Definition Classes
Any
final def ##(): Int

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

Definition Classes
AnyRef
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
AnyRef
Annotations
@throws()
final def eq(arg0: AnyRef): Boolean

Definition Classes
AnyRef
def equals(arg0: Any): Boolean

Definition Classes
AnyRef → Any
def finalize(): Unit

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
@throws()
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
AnyRef
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
AnyRef
def toString(): String

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

Definition Classes
AnyRef
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 Length[T] extends AnyRef

Abstract Value Members

abstract def lengthOf(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

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