abstract class AbstractPartialFunction[-T1, +R] extends (T1) ⇒ R with PartialFunction[T1, R]
AbstractPartialFunction reformulates all operations of its supertrait PartialFunction
in terms of isDefinedAt and applyOrElse.
This allows more efficient implementations in many cases:
- optimized
orElsemethod supports chainedorElsein linear time, and with no slow-down if theorElsepart is not needed. - optimized
liftmethod helps to avoid double evaluation of pattern matchers & guards of partial function literals.
This trait is used as a basis for implementation of all partial function literals.
- Self Type
- AbstractPartialFunction[T1, R]
- Source
- AbstractPartialFunction.scala
- Since
2.10
- Alphabetic
- By Inheritance
- AbstractPartialFunction
- PartialFunction
- Function1
- AnyRef
- Any
- by any2stringadd
- by StringFormat
- by Ensuring
- by ArrowAssoc
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- Public
- All
Instance Constructors
- new AbstractPartialFunction()
Abstract Value Members
-
abstract
def
isDefinedAt(x: T1): Boolean
Checks if a value is contained in the function's domain.
Checks if a value is contained in the function's domain.
- x
the value to test
- returns
true, iffxis in the domain of this function,falseotherwise.
- Definition Classes
- PartialFunction
Concrete Value Members
-
final
def
!=(arg0: Any): Boolean
Test two objects for inequality.
Test two objects for inequality.
- returns
trueif !(this == that), false otherwise.
- Definition Classes
- AnyRef → Any
-
final
def
##(): Int
Equivalent to
x.hashCodeexcept for boxed numeric types andnull.Equivalent to
x.hashCodeexcept for boxed numeric types andnull. 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. Fornullreturns a hashcode wherenull.hashCodethrows aNullPointerException.- returns
a hash value consistent with ==
- Definition Classes
- AnyRef → Any
-
def
+(other: String): String
- Implicit
- This member is added by an implicit conversion from AbstractPartialFunction[T1, R] to any2stringadd[AbstractPartialFunction[T1, R]] performed by method any2stringadd in scala.Predef.
- Definition Classes
- any2stringadd
-
def
->[B](y: B): (AbstractPartialFunction[T1, R], B)
- Implicit
- This member is added by an implicit conversion from AbstractPartialFunction[T1, R] to ArrowAssoc[AbstractPartialFunction[T1, R]] performed by method ArrowAssoc in scala.Predef.
- Definition Classes
- ArrowAssoc
- Annotations
- @inline()
-
final
def
==(arg0: Any): Boolean
The expression
x == thatis equivalent toif (x eq null) that eq null else x.equals(that).The expression
x == thatis equivalent toif (x eq null) that eq null else x.equals(that).- returns
trueif the receiver object is equivalent to the argument;falseotherwise.
- Definition Classes
- AnyRef → Any
-
def
andThen[C](k: (R) ⇒ C): PartialFunction[T1, C]
Composes this partial function with a transformation function that gets applied to results of this partial function.
Composes this partial function with a transformation function that gets applied to results of this partial function.
- C
the result type of the transformation function.
- k
the transformation function
- returns
a partial function with the same domain as this partial function, which maps arguments
xtok(this(x)).
- Definition Classes
- PartialFunction → Function1
-
def
apply(x: T1): R
Apply the body of this function to the argument.
Apply the body of this function to the argument.
- returns
the result of function application.
- Definition Classes
- AbstractPartialFunction → Function1
-
def
applyOrElse[A1 <: T1, B1 >: R](x: A1, default: (A1) ⇒ B1): B1
Applies this partial function to the given argument when it is contained in the function domain.
Applies this partial function to the given argument when it is contained in the function domain. Applies fallback function where this partial function is not defined.
Note that expression
pf.applyOrElse(x, default)is equivalent toif(pf isDefinedAt x) pf(x) else default(x)
except that
applyOrElsemethod can be implemented more efficiently. For all partial function literals the compiler generates anapplyOrElseimplementation which avoids double evaluation of pattern matchers and guards. This makesapplyOrElsethe basis for the efficient implementation for many operations and scenarios, such as:- combining partial functions into
orElse/andThenchains does not lead to excessiveapply/isDefinedAtevaluation liftandunliftdo not evaluate source functions twice on each invocationrunWithallows efficient imperative-style combining of partial functions with conditionally applied actions
For non-literal partial function classes with nontrivial
isDefinedAtmethod it is recommended to overrideapplyOrElsewith custom implementation that avoids doubleisDefinedAtevaluation. This may result in better performance and more predictable behavior w.r.t. side effects.- x
the function argument
- default
the fallback function
- returns
the result of this function or fallback function application.
- Definition Classes
- PartialFunction
- Since
2.10
- combining partial functions into
-
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 aClassCastExceptionat runtime, while the expressionList(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
ClassCastExceptionif the receiver object is not an instance of the erasure of typeT0.
-
def
clone(): AnyRef
Create a copy of the receiver object.
-
def
compose[A](g: (A) ⇒ T1): (A) ⇒ R
Composes two instances of Function1 in a new Function1, with this function applied last.
Composes two instances of Function1 in a new Function1, with this function applied last.
- A
the type to which function
gcan be applied- g
a function A => T1
- returns
a new function
fsuch thatf(x) == apply(g(x))
- Definition Classes
- Function1
- Annotations
- @unspecialized()
-
def
ensuring(cond: (AbstractPartialFunction[T1, R]) ⇒ Boolean, msg: ⇒ Any): AbstractPartialFunction[T1, R]
- Implicit
- This member is added by an implicit conversion from AbstractPartialFunction[T1, R] to Ensuring[AbstractPartialFunction[T1, R]] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
-
def
ensuring(cond: (AbstractPartialFunction[T1, R]) ⇒ Boolean): AbstractPartialFunction[T1, R]
- Implicit
- This member is added by an implicit conversion from AbstractPartialFunction[T1, R] to Ensuring[AbstractPartialFunction[T1, R]] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
-
def
ensuring(cond: Boolean, msg: ⇒ Any): AbstractPartialFunction[T1, R]
- Implicit
- This member is added by an implicit conversion from AbstractPartialFunction[T1, R] to Ensuring[AbstractPartialFunction[T1, R]] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
-
def
ensuring(cond: Boolean): AbstractPartialFunction[T1, R]
- Implicit
- This member is added by an implicit conversion from AbstractPartialFunction[T1, R] to Ensuring[AbstractPartialFunction[T1, R]] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
-
final
def
eq(arg0: AnyRef): Boolean
Tests whether the argument (
that) is a reference to the receiver object (this).Tests whether the argument (
that) is a reference to the receiver object (this).The
eqmethod implements an equivalence relation on non-null instances ofAnyRef, and has three additional properties:- It is consistent: for any non-null instances
xandyof typeAnyRef, multiple invocations ofx.eq(y)consistently returnstrueor consistently returnsfalse. - For any non-null instance
xof typeAnyRef,x.eq(null)andnull.eq(x)returnsfalse. null.eq(null)returnstrue.
When overriding the
equalsorhashCodemethods, 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
trueif the argument is a reference to the receiver object;falseotherwise.
- Definition Classes
- AnyRef
- It is consistent: for any non-null instances
-
def
equals(arg0: Any): Boolean
The equality method for reference types.
-
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
finalizemethod is invoked, as well as the interaction betweenfinalizeand non-local returns and exceptions, are all platform dependent.- Attributes
- protected[lang]
- Definition Classes
- AnyRef
- Annotations
- @throws( classOf[java.lang.Throwable] )
- Note
not specified by SLS as a member of AnyRef
-
def
formatted(fmtstr: String): String
Returns string formatted according to given
formatstring.Returns string formatted according to given
formatstring. Format strings are as forString.format(@see java.lang.String.format).- Implicit
- This member is added by an implicit conversion from AbstractPartialFunction[T1, R] to Predef.StringFormat[AbstractPartialFunction[T1, R]] performed by method StringFormat in scala.Predef.
- Definition Classes
- StringFormat
- Annotations
- @inline()
-
final
def
getClass(): Class[_]
Returns the runtime class representation of the object.
-
def
hashCode(): Int
The hashCode method for reference types.
-
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 returnfalse, while the expressionList(1).isInstanceOf[List[String]]will returntrue. 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
trueif the receiver object is an instance of erasure of typeT0;falseotherwise.
- Definition Classes
- Any
-
def
lift: (T1) ⇒ Option[R]
Turns this partial function into a plain function returning an
Optionresult.Turns this partial function into a plain function returning an
Optionresult.- returns
a function that takes an argument
xtoSome(this(x))ifthisis defined forx, and toNoneotherwise.
- Definition Classes
- PartialFunction
- See also
Function.unlift
-
final
def
ne(arg0: AnyRef): Boolean
Equivalent to
!(this eq that).Equivalent to
!(this eq that).- returns
trueif the argument is not a reference to the receiver object;falseotherwise.
- 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
- Annotations
- @native()
- 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
- Annotations
- @native()
- Note
not specified by SLS as a member of AnyRef
-
def
orElse[A1 <: T1, B1 >: R](that: PartialFunction[A1, B1]): PartialFunction[A1, B1]
Composes this partial function with a fallback partial function which gets applied where this partial function is not defined.
Composes this partial function with a fallback partial function which gets applied where this partial function is not defined.
- A1
the argument type of the fallback function
- B1
the result type of the fallback function
- that
the fallback function
- returns
a partial function which has as domain the union of the domains of this partial function and
that. The resulting partial function takesxtothis(x)wherethisis defined, and tothat(x)where it is not.
- Definition Classes
- PartialFunction
-
def
runWith[U](action: (R) ⇒ U): (T1) ⇒ Boolean
Composes this partial function with an action function which gets applied to results of this partial function.
Composes this partial function with an action function which gets applied to results of this partial function. The action function is invoked only for its side effects; its result is ignored.
Note that expression
pf.runWith(action)(x)is equivalent toif(pf isDefinedAt x) { action(pf(x)); true } else false
except that
runWithis implemented viaapplyOrElseand thus potentially more efficient. UsingrunWithavoids double evaluation of pattern matchers and guards for partial function literals.- action
the action function
- returns
a function which maps arguments
xtoisDefinedAt(x). The resulting function runsaction(this(x))wherethisis defined.
- Definition Classes
- PartialFunction
- Since
2.10
- See also
applyOrElse.
-
final
def
synchronized[T0](arg0: ⇒ T0): T0
- Definition Classes
- AnyRef
-
def
toString(): String
Creates a String representation of this object.
-
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
-
def
→[B](y: B): (AbstractPartialFunction[T1, R], B)
- Implicit
- This member is added by an implicit conversion from AbstractPartialFunction[T1, R] to ArrowAssoc[AbstractPartialFunction[T1, R]] performed by method ArrowAssoc in scala.Predef.
- Definition Classes
- ArrowAssoc
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