BaseStream
public
interface
BaseStream
implements
AutoCloseable
| java.util.stream.BaseStream<T, S extends java.util.stream.BaseStream<T, S>> |
Base interface for streams, which are sequences of elements supporting
sequential and parallel aggregate operations. The following example
illustrates an aggregate operation using the stream types Stream
and IntStream, computing the sum of the weights of the red widgets:
int sum = widgets.stream()
.filter(w -> w.getColor() == RED)
.mapToInt(w -> w.getWeight())
.sum();
Stream and the package documentation
for java.util.stream for additional
specification of streams, stream operations, stream pipelines, and
parallelism, which governs the behavior of all stream types.
Summary
Public methods | |
|---|---|
abstract
void
|
close()
Closes this stream, causing all close handlers for this stream pipeline to be called. |
abstract
boolean
|
isParallel()
Returns whether this stream, if a terminal operation were to be executed, would execute in parallel. |
abstract
Iterator<T>
|
iterator()
Returns an iterator for the elements of this stream. |
abstract
S
|
onClose(Runnable closeHandler)
Returns an equivalent stream with an additional close handler. |
abstract
S
|
parallel()
Returns an equivalent stream that is parallel. |
abstract
S
|
sequential()
Returns an equivalent stream that is sequential. |
abstract
Spliterator<T>
|
spliterator()
Returns a spliterator for the elements of this stream. |
abstract
S
|
unordered()
Returns an equivalent stream that is unordered. |
Inherited methods | |
|---|---|
Public methods
close
public abstract void close ()
Closes this stream, causing all close handlers for this stream pipeline to be called.
See also:
isParallel
public abstract boolean isParallel ()
Returns whether this stream, if a terminal operation were to be executed, would execute in parallel. Calling this method after invoking an terminal stream operation method may yield unpredictable results.
| Returns | |
|---|---|
boolean |
true if this stream would execute in parallel if executed |
iterator
public abstract Iterator<T> iterator ()
Returns an iterator for the elements of this stream.
This is a terminal operation.
API Note:
- This operation is provided as an "escape hatch" to enable arbitrary client-controlled pipeline traversals in the event that the existing operations are not sufficient to the task.
| Returns | |
|---|---|
Iterator<T> |
the element iterator for this stream |
onClose
public abstract S onClose (Runnable closeHandler)
Returns an equivalent stream with an additional close handler. Close
handlers are run when the close() method
is called on the stream, and are executed in the order they were
added. All close handlers are run, even if earlier close handlers throw
exceptions. If any close handler throws an exception, the first
exception thrown will be relayed to the caller of close(), with
any remaining exceptions added to that exception as suppressed exceptions
(unless one of the remaining exceptions is the same exception as the
first exception, since an exception cannot suppress itself.) May
return itself.
This is an intermediate operation.
| Parameters | |
|---|---|
closeHandler |
Runnable: A task to execute when the stream is closed |
| Returns | |
|---|---|
S |
a stream with a handler that is run if the stream is closed |
parallel
public abstract S parallel ()
Returns an equivalent stream that is parallel. May return itself, either because the stream was already parallel, or because the underlying stream state was modified to be parallel.
This is an intermediate operation.
| Returns | |
|---|---|
S |
a parallel stream |
sequential
public abstract S sequential ()
Returns an equivalent stream that is sequential. May return itself, either because the stream was already sequential, or because the underlying stream state was modified to be sequential.
This is an intermediate operation.
| Returns | |
|---|---|
S |
a sequential stream |
spliterator
public abstract Spliterator<T> spliterator ()
Returns a spliterator for the elements of this stream.
This is a terminal operation.
API Note:
- This operation is provided as an "escape hatch" to enable
arbitrary client-controlled pipeline traversals in the event that the
existing operations are not sufficient to the task.
The returned spliterator should report the set of characteristics derived from the stream pipeline (namely the characteristics derived from the stream source spliterator and the intermediate operations). Implementations may report a sub-set of those characteristics. For example, it may be too expensive to compute the entire set for some or all possible stream pipelines.
| Returns | |
|---|---|
Spliterator<T> |
the element spliterator for this stream |
unordered
public abstract S unordered ()
Returns an equivalent stream that is unordered. May return itself, either because the stream was already unordered, or because the underlying stream state was modified to be unordered.
This is an intermediate operation.
| Returns | |
|---|---|
S |
an unordered stream |