Ordered

trait Ordered[A] extends Comparable[A]

A trait for data that have a single, natural ordering. See Ordering before using this trait for more information about whether to use Ordering instead.

Classes that implement this trait can be sorted with scala.utils.Sorting and can be compared with standard comparison operators (e.g. > and <).

Ordered should be used for data with a single, natural ordering (like integers) while Ordering allows for multiple ordering implementations. An Ordering instance will be implicitly created if necessary.

Ordering is an alternative to this trait that allows multiple orderings to be defined for the same type.

PartiallyOrdered is an alternative to this trait for partially ordered data.

For example, to create a simple class that implements Ordered and then sort it with scala.utils.Sorting:

 class OrderedClass(n:Int) extends Ordered[OrderedClass] {
 	def compare(that: OrderedClass) =  this.n - that.n
 }

 val x = List(new MyClass(1), new MyClass(5), new MyClass(3))
 val result = scala.utils.Sorting.quickSort(x)

It is important that the equals method for an instance of Ordered[A] be consistent with the compare method. However, due to limitations inherent in the type erasure semantics, there is no reasonable way to provide a default implementation of equality for instances of Ordered[A]. Therefore, if you need to be able to use equality on an instance of Ordered[A] you must provide it yourself either when inheriting or instantiating.

It is important that the hashCode method for an instance of Ordered[A] be consistent with the compare method. However, it is not possible to provide a sensible default implementation. Therefore, if you need to be able compute the hash of an instance of Ordered[A] you must provide it yourself either when inheriting or instantiating.

Source: Ordered.scala
Version: 1.1, 2006-07-24
See also: Ordering, PartiallyOrdered

Linear Supertypes

Comparable[A], AnyRef, Any

Known Subclasses

FractionalProxy, IntegralProxy, OrderedProxy, RichBoolean, RichByte, RichChar, RichDouble, RichFloat, RichInt, RichLong, RichShort, ScalaNumberProxy, ScalaWholeNumberProxy, StringBuilder, StringLike, StringOps, Val, Value, Value, WrappedString

Ordering

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By inheritance

Inherited

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Ordered
Comparable
AnyRef
Any

Visibility

Public
All

Abstract Value Members

abstract def compare(that: A): Int

Result of comparing this with operand that.
Result of comparing this with operand that.
Implement this method to determine how instances of A will be sorted.
Returns x where:
- x < 0 when this < that
- x == 0 when this == that
- x > 0 when this > that

Concrete Value Members

final def !=(arg0: AnyRef): Boolean

Definition Classes
AnyRef
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
final def ##(): Int

Equivalent to x.hashCode except for boxed numeric types.
Equivalent to x.hashCode except for boxed numeric types. 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.
returns
a hash value consistent with ==

Definition Classes
AnyRef → Any
def <(that: A): Boolean

Returns true if this is less than that
def <=(that: A): Boolean

Returns true if this is less than or equal to that.
final def ==(arg0: AnyRef): Boolean

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

Test two objects for equality.
Test two objects for equality.
returns
true if the receiver object is equivalent to the argument; false otherwise.

Definition Classes
Any
def >(that: A): Boolean

Returns true if this is greater than that.
def >=(that: A): Boolean

Returns true if this is greater than or equal to that.
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.
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[lang]
Definition Classes
AnyRef
Annotations
@throws()
Note
not specified by SLS as a member of AnyRef
def compareTo(that: A): Int

Result of comparing this with operand that.
Result of comparing this with operand that.

Definition Classes
Ordered → Comparable
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
def equals(arg0: Any): Boolean

The equality method for reference types.
The equality method for reference types. See equals in Any.
returns
true if the receiver object is equivalent to the argument; false otherwise.

Definition Classes
AnyRef → Any
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[lang]
Definition Classes
AnyRef
Annotations
@throws()
Note
not specified by SLS as a member of AnyRef
final def getClass(): java.lang.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
def hashCode(): Int

The hashCode method for reference types.
The hashCode method for reference types. See hashCode in Any.
returns
the hash code value for this object.

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

Definition Classes
AnyRef
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
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()

Inherited from Comparable[A]

Inherited from AnyRef

Inherited from Any