E1
- Type of the first free variable, i.e. the element the closure is called on.E2
- Type of the second free variable, i.e. the element the closure is called on.R
- Type of the closure's return value.public interface IgniteReducer2<E1,E2,R> extends IgniteOutClosure<R>
for-all
or reduce
type of closure. Unlike for-each
type of closure
that returns optional value on each execution of the closure - the reducer returns a single
value for one or more collected values.
Closures are a first-class functions that are defined with (or closed over) their free variables that are bound to the closure scope at execution. Since Java 6 doesn't provide a language construct for first-class function the closures are implemented as abstract classes.
Modifier and Type | Method and Description |
---|---|
boolean |
collect(E1 e1,
E2 e2)
Collects given values.
|
apply
boolean collect(@Nullable E1 e1, @Nullable E2 e2)
IgniteOutClosure.apply()
method.
The null
s could be passed if the data being collected is indeed null
.
If execution failed this method will not be called.
e1
- First bound free variable, i.e. the element the closure is called on.e2
- Second bound free variable, i.e. the element the closure is called on.true
to continue collecting, false
to instruct caller to stop
collecting and call IgniteOutClosure.apply()
method.
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Ignite Fabric : ver. 1.9.0 Release Date : March 2 2017