Trait scala.concurrent.ExecutionContext
Companion object ExecutionContext
trait ExecutionContext extends AnyRef
Abstract Value Members
abstract def execute(runnable: Runnable): Unit
Runs a block of code on this execution context.
- runnable
the task to execute
abstract def reportFailure(cause: Throwable): Unit
Reports that an asynchronous computation failed.
- cause
the cause of the failure
Concrete Value Members
final def !=(arg0: Any): Boolean
Test two objects for inequality.
- returns
true
if !(this == that), false otherwise.
- Definition Classes
- AnyRef → Any
final def ##(): Int
Equivalent to x.hashCode
except for boxed numeric types and null
. 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. For null
returns a hashcode where null.hashCode
throws a NullPointerException
.
- returns
a hash value consistent with ==
- Definition Classes
- AnyRef → Any
def +(other: String): String
- Implicit
- This member is added by an implicit conversion from ExecutionContext to any2stringadd[ExecutionContext] performed by method any2stringadd in scala.Predef.
- Definition Classes
- any2stringadd
def ->[B](y: B): (ExecutionContext, B)
- Implicit
- This member is added by an implicit conversion from ExecutionContext to ArrowAssoc[ExecutionContext] performed by method ArrowAssoc in scala.Predef.
- Definition Classes
- ArrowAssoc
- Annotations
- @inline()
final def ==(arg0: Any): Boolean
The expression x == that
is equivalent to if (x eq null) that eq null else x.equals(that)
.
- returns
true
if the receiver object is equivalent to the argument;false
otherwise.
- Definition Classes
- AnyRef → Any
final def asInstanceOf[T0]: 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 typeT0
.
def clone(): AnyRef
Create a copy of the receiver object.
The default implementation of the clone
method is platform dependent.
- returns
a copy of the receiver object.
def ensuring(cond: (ExecutionContext) ⇒ Boolean, msg: ⇒ Any): ExecutionContext
- Implicit
- This member is added by an implicit conversion from ExecutionContext to Ensuring[ExecutionContext] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
def ensuring(cond: (ExecutionContext) ⇒ Boolean): ExecutionContext
- Implicit
- This member is added by an implicit conversion from ExecutionContext to Ensuring[ExecutionContext] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
def ensuring(cond: Boolean, msg: ⇒ Any): ExecutionContext
- Implicit
- This member is added by an implicit conversion from ExecutionContext to Ensuring[ExecutionContext] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
def ensuring(cond: Boolean): ExecutionContext
- Implicit
- This member is added by an implicit conversion from ExecutionContext to Ensuring[ExecutionContext] 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
).
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. Default implementation delegates to eq
.
See also equals
in scala.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.
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( 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 format
string. Format strings are as for String.format
(@see java.lang.String.format).
- Implicit
- This member is added by an implicit conversion from ExecutionContext to StringFormat[ExecutionContext] performed by method StringFormat in scala.Predef.
- Definition Classes
- StringFormat
- Annotations
- @inline()
final def getClass(): Class[_]
Returns the runtime class representation of the object.
- returns
a class object corresponding to the runtime type of the receiver.
def hashCode(): Int
The hashCode method for reference types. See hashCode in scala.Any.
- returns
the hash code value for this object.
final def isInstanceOf[T0]: Boolean
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 typeT0
;false
otherwise.
- Definition Classes
- Any
final def ne(arg0: AnyRef): Boolean
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.
- 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.
- Definition Classes
- AnyRef
- Annotations
- @native()
- 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. 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
def →[B](y: B): (ExecutionContext, B)
- Implicit
- This member is added by an implicit conversion from ExecutionContext to ArrowAssoc[ExecutionContext] performed by method ArrowAssoc in scala.Predef.
- Definition Classes
- ArrowAssoc
© 2002-2019 EPFL, with contributions from Lightbend.
Licensed under the Apache License, Version 2.0.
https://www.scala-lang.org/api/2.12.9/scala/concurrent/ExecutionContext.html
An
ExecutionContext
can execute program logic asynchronously, typically but not necessarily on a thread pool.A general purpose
ExecutionContext
must be asynchronous in executing anyRunnable
that is passed into itsexecute
-method. A special purposeExecutionContext
may be synchronous but must only be passed to code that is explicitly safe to be run using a synchronously executingExecutionContext
.APIs such as
Future.onComplete
require you to provide a callback and an implicitExecutionContext
. The implicitExecutionContext
will be used to execute the callback.While it is possible to simply import
scala.concurrent.ExecutionContext.Implicits.global
to obtain an implicitExecutionContext
, application developers should carefully consider where they want to set execution policy; ideally, one place per application—or per logically related section of code— will make a decision about whichExecutionContext
to use. That is, you will mostly want to avoid hardcoding, especially via an import,scala.concurrent.ExecutionContext.Implicits.global
. The recommended approach is to add(implicit ec: ExecutionContext)
to methods, or class constructor parameters, which need anExecutionContext
.Then locally import a specific
ExecutionContext
in one place for the entire application or module, passing it implicitly to individual methods. Alternatively define a local implicit val with the requiredExecutionContext
.A custom
ExecutionContext
may be appropriate to execute code which blocks on IO or performs long-running computations.ExecutionContext.fromExecutorService
andExecutionContext.fromExecutor
are good ways to create a customExecutionContext
.The intent of
ExecutionContext
is to lexically scope code execution. That is, each method, class, file, package, or application determines how to run its own code. This avoids issues such as running application callbacks on a thread pool belonging to a networking library. The size of a networking library's thread pool can be safely configured, knowing that only that library's network operations will be affected. Application callback execution can be configured separately.