Package io.activej.csp

Class ChannelSuppliers

java.lang.Object

io.activej.csp.ChannelSuppliers

public final class ChannelSuppliers
extends Object

Provides additional functionality for managing ChannelSuppliers. Includes helper classes: ChannelSupplierOfException, ChannelSupplierOfIterator, ChannelSupplierOfValue, ChannelSupplierEmpty.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final class	ChannelSuppliers.ChannelSupplierConcat<T>
static class	ChannelSuppliers.ChannelSupplierEmpty<T>	Represents a ChannelSupplier which always returns a promise of null.
static final class	ChannelSuppliers.ChannelSupplierOfException<T>	Represents a ChannelSupplier which always returns a promise of exception.
static final class	ChannelSuppliers.ChannelSupplierOfIterator<T>	Represents a ChannelSupplier which wraps the provided iterator and returns promises of iterator's values until hasNext() is true, when there are no more values left, a promise of null is returned.
static final class	ChannelSuppliers.ChannelSupplierOfValue<T>	Represents a ChannelSupplier of one value.

Constructor Summary

Constructors

Constructor	Description
ChannelSuppliers()

Method Summary

Modifier and Type	Method	Description
static InputStream	channelSupplierAsInputStream(io.activej.eventloop.Eventloop eventloop, ChannelSupplier<io.activej.bytebuf.ByteBuf> channelSupplier)	Creates an InputStream out of a ChannelSupplier<io.activej.bytebuf.ByteBuf>.
static <T, A, R> io.activej.promise.Promise<R>	collect(ChannelSupplier<T> supplier, A initialValue, io.activej.common.function.BiConsumerEx<A,T> accumulator, io.activej.common.function.FunctionEx<A,R> finisher)	Collects data provided by the supplier asynchronously and returns a promise of accumulated result.
static <T> ChannelSupplier<T>	concat(ChannelSupplier<? extends T>... suppliers)
static <T> ChannelSupplier<T>	concat(ChannelSupplier<? extends T> supplier1, ChannelSupplier<? extends T> supplier2)
static <T> ChannelSupplier<T>	concat(Iterator<? extends ChannelSupplier<? extends T>> iterator)	Creates a new ChannelSupplier which on get() call returns the result wrapped in promise of the first ChannelSuppliers' promise that was successfully completed with a non-null result.
static <T> ChannelSupplier<T>	concat(List<ChannelSupplier<? extends T>> suppliers)
static ChannelSupplier<io.activej.bytebuf.ByteBuf>	inputStreamAsChannelSupplier(Executor executor, int bufSize, InputStream inputStream)	Creates an asynchronous ChannelSupplier<io.activej.bytebuf.ByteBuf> out of some InputStream.
static ChannelSupplier<io.activej.bytebuf.ByteBuf>	inputStreamAsChannelSupplier(Executor executor, io.activej.common.MemSize bufSize, InputStream is)
static ChannelSupplier<io.activej.bytebuf.ByteBuf>	inputStreamAsChannelSupplier(Executor executor, InputStream is)	Creates an asynchronous ChannelSupplier out of some InputStream.
static <T> ChannelSupplier<T>	prefetch(int count, ChannelSupplier<T> actual)
static <T> ChannelSupplier<T>	prefetch(ChannelSupplier<T> actual)
static <T, V> ChannelSupplier<V>	remap(ChannelSupplier<T> supplier, Function<? super T,? extends Iterator<? extends V>> fn)	Transforms this ChannelSupplier data of type with provided fn, which returns an Iterator of a type.
static <T> io.activej.promise.Promise<Void>	streamTo(io.activej.common.collection.Try<ChannelSupplier<T>> supplier, io.activej.common.collection.Try<ChannelConsumer<T>> consumer)
static <T> io.activej.promise.Promise<Void>	streamTo(ChannelSupplier<T> supplier, ChannelConsumer<T> consumer)	Streams data from the supplier to the consumer until get() of supplier returns a promise of null.
static <T> io.activej.promise.Promise<Void>	streamTo(io.activej.promise.Promise<ChannelSupplier<T>> supplier, io.activej.promise.Promise<ChannelConsumer<T>> consumer)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

ChannelSuppliers

public ChannelSuppliers()

Method Details

concat

public static <T> ChannelSupplier<T> concat(ChannelSupplier<? extends T> supplier1,
 ChannelSupplier<? extends T> supplier2)

See Also:

• concat(Iterator)

concat

@SafeVarargs
public static <T> ChannelSupplier<T> concat(ChannelSupplier<? extends T>... suppliers)

See Also:

• concat(Iterator)

concat

public static <T> ChannelSupplier<T> concat(List<ChannelSupplier<? extends T>> suppliers)

See Also:

• concat(Iterator)

concat

public static <T> ChannelSupplier<T> concat(Iterator<? extends ChannelSupplier<? extends T>> iterator)

Creates a new ChannelSupplier which on get() call returns the result wrapped in promise of the first ChannelSuppliers' promise that was successfully completed with a non-null result. If all the ChannelSuppliers of the iterator have a null promise result, a promise of null will be returned.

If one of the ChannelSuppliers' promises completes with an exception, all subsequent elements of the iterator will be closed and a promise of exception will be returned.

Type Parameters:

T - type of data wrapped in the ChannelSuppliers

Parameters:

iterator - an iterator of ChannelSuppliers

Returns:

a ChannelSupplier of <T>

collect

public static <T,
A,
R> io.activej.promise.Promise<R> collect(ChannelSupplier<T> supplier,
 A initialValue,
 io.activej.common.function.BiConsumerEx<A,T> accumulator,
 io.activej.common.function.FunctionEx<A,R> finisher)

Collects data provided by the supplier asynchronously and returns a promise of accumulated result. This process will be getting values from the supplier, until a promise of null is returned, which represents end of stream.

If get returns a promise of exception or there was an exception while accumulator accepted values, a promise of exception will be returned and the process will stop.

Type Parameters:

T - a data type provided by the supplier

A - an intermediate accumulation data type

R - a data type of final result of finisher

Parameters:

supplier - a ChannelSupplier which provides data to be collected

initialValue - a value which will accumulate the results of accumulator

accumulator - a BiConsumer which may perform some operations over provided by supplier data and accumulates the result to the initialValue

finisher - a Function which performs the final transformation of the accumulated value

Returns:

a promise of accumulated result, transformed by the finisher

streamTo

public static <T> io.activej.promise.Promise<Void> streamTo(io.activej.promise.Promise<ChannelSupplier<T>> supplier,
 io.activej.promise.Promise<ChannelConsumer<T>> consumer)

streamTo

public static <T> io.activej.promise.Promise<Void> streamTo(io.activej.common.collection.Try<ChannelSupplier<T>> supplier,
 io.activej.common.collection.Try<ChannelConsumer<T>> consumer)

streamTo

public static <T> io.activej.promise.Promise<Void> streamTo(ChannelSupplier<T> supplier,
 ChannelConsumer<T> consumer)

Streams data from the supplier to the consumer until get() of supplier returns a promise of null.

If get returns a promise of exception or there was an exception while consumer accepted values, a promise of exception will be returned and the process will stop.

Type Parameters:

T - a data type of values passed from the supplier to consumer

Parameters:

supplier - a supplier which provides some data

consumer - a consumer which accepts the provided by supplier data

Returns:

a promise of null as a marker of completion of stream, or promise of exception, if there was an exception while streaming

prefetch

public static <T> ChannelSupplier<T> prefetch(int count,
 ChannelSupplier<T> actual)

prefetch

public static <T> ChannelSupplier<T> prefetch(ChannelSupplier<T> actual)

remap

public static <T,
V> ChannelSupplier<V> remap(ChannelSupplier<T> supplier,
 Function<? super T,? extends Iterator<? extends V>> fn)

Transforms this ChannelSupplier data of type with provided fn, which returns an Iterator of a type. Then provides this value to ChannelSupplier of .

inputStreamAsChannelSupplier

public static ChannelSupplier<io.activej.bytebuf.ByteBuf> inputStreamAsChannelSupplier(Executor executor,
 io.activej.common.MemSize bufSize,
 InputStream is)

See Also:

• inputStreamAsChannelSupplier(Executor, int, InputStream)

inputStreamAsChannelSupplier

public static ChannelSupplier<io.activej.bytebuf.ByteBuf> inputStreamAsChannelSupplier(Executor executor,
 InputStream is)

Creates an asynchronous ChannelSupplier out of some InputStream.

Uses a default buffer size of 8 kilobytes

See Also:

• inputStreamAsChannelSupplier(Executor, int, InputStream)

inputStreamAsChannelSupplier

public static ChannelSupplier<io.activej.bytebuf.ByteBuf> inputStreamAsChannelSupplier(Executor executor,
 int bufSize,
 InputStream inputStream)

Creates an asynchronous ChannelSupplier<io.activej.bytebuf.ByteBuf> out of some InputStream.

I/O operations are executed using a specified Executor, so that the channel supplier operations does not block the eventloop thread.

A size of a ByteBuf returned by ChannelSupplier.get() will not exceed specified limit

Passed InputStream will be closed once a resulting ChannelSupplier<io.activej.bytebuf.ByteBuf> is closed or in case an error occurs during channel supplier operations.

This method should be called from within eventloop thread

Parameters:

executor - an executor that will execute blocking I/O

bufSize - a limit on a size of a byte buf supplied by returned ChannelSupplier<io.activej.bytebuf.ByteBuf>

inputStream - an InputStream that is transformed into a ChannelSupplier<io.activej.bytebuf.ByteBuf>

Returns:

a ChannelSupplier<io.activej.bytebuf.ByteBuf> out ouf an InputStream

channelSupplierAsInputStream

public static InputStream channelSupplierAsInputStream(io.activej.eventloop.Eventloop eventloop,
 ChannelSupplier<io.activej.bytebuf.ByteBuf> channelSupplier)

Creates an InputStream out of a ChannelSupplier<io.activej.bytebuf.ByteBuf>.

Asynchronous operations are executed in a context of a specified Eventloop

Passed ChannelSupplier<io.activej.bytebuf.ByteBuf> will be closed once a resulting InputStream is closed or in case an error occurs while reading data.

InputStream's methods are blocking, so they should not be called from an eventloop thread

Parameters:

eventloop - an eventloop that will execute asynchronous operations

channelSupplier - a ChannelSupplier<io.activej.bytebuf.ByteBuf> that is transformed to an InputStream

Returns:

an InputStream out ouf a ChannelSupplier<io.activej.bytebuf.ByteBuf>