| /* |
| * Copyright 2016-2017 JetBrains s.r.o. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| @file:JvmMultifileClass |
| @file:JvmName("ChannelsKt") |
| |
| package kotlinx.coroutines.experimental.channels |
| |
| import kotlinx.coroutines.experimental.* |
| import kotlinx.coroutines.experimental.internalAnnotations.* |
| import kotlin.coroutines.experimental.* |
| |
| internal const val DEFAULT_CLOSE_MESSAGE = "Channel was closed" |
| |
| |
| // -------- Conversions to ReceiveChannel -------- |
| |
| /** |
| * Returns a channel to read all element of the [Iterable]. |
| */ |
| public fun <E> Iterable<E>.asReceiveChannel(context: CoroutineContext = Unconfined): ReceiveChannel<E> = |
| produce(context) { |
| for (element in this@asReceiveChannel) |
| send(element) |
| } |
| |
| /** |
| * Returns a channel to read all element of the [Sequence]. |
| */ |
| public fun <E> Sequence<E>.asReceiveChannel(context: CoroutineContext = Unconfined): ReceiveChannel<E> = |
| produce(context) { |
| for (element in this@asReceiveChannel) |
| send(element) |
| } |
| |
| // -------- Operations on BroadcastChannel -------- |
| |
| /** |
| * Opens subscription to this [BroadcastChannel] and makes sure that the given [block] consumes all elements |
| * from it by always invoking [cancel][ReceiveChannel.cancel] after the execution of the block. |
| */ |
| public inline fun <E, R> BroadcastChannel<E>.consume(block: ReceiveChannel<E>.() -> R): R { |
| val channel = openSubscription() |
| try { |
| return channel.block() |
| } finally { |
| channel.cancel() |
| } |
| } |
| |
| /** |
| * Subscribes to this [BroadcastChannel] and performs the specified action for each received element. |
| */ |
| public suspend inline fun <E> BroadcastChannel<E>.consumeEach(action: (E) -> Unit) = |
| consume { |
| for (element in this) action(element) |
| } |
| |
| /** |
| * @suppress: **Deprecated**: binary compatibility with old code |
| */ |
| @Deprecated("binary compatibility with old code", level = DeprecationLevel.HIDDEN) |
| public suspend fun <E> BroadcastChannel<E>.consumeEach(action: suspend (E) -> Unit) = |
| consumeEach { action(it) } |
| |
| // -------- Operations on ReceiveChannel -------- |
| |
| /** |
| * Returns a [CompletionHandler] that invokes [cancel][ReceiveChannel.cancel] on the [ReceiveChannel] |
| * with the corresponding cause. See also [ReceiveChannel.consume]. |
| * |
| * **WARNING**: It is planned that in the future a second invocation of this method |
| * on an channel that is already being consumed is going to fail fast, that it |
| * immediately throws an [IllegalStateException]. |
| * See [this issue](https://github.com/Kotlin/kotlinx.coroutines/issues/167) |
| * for details. |
| */ |
| public fun ReceiveChannel<*>.consumes(): CompletionHandler = |
| { cause: Throwable? -> cancel(cause) } |
| |
| /** |
| * Returns a [CompletionHandler] that invokes [cancel][ReceiveChannel.cancel] on all the |
| * specified [ReceiveChannel] instances with the corresponding cause. |
| * See also [ReceiveChannel.consumes()] for a version on one channel. |
| */ |
| public fun consumesAll(vararg channels: ReceiveChannel<*>): CompletionHandler = |
| { cause: Throwable? -> |
| var exception: Throwable? = null |
| for (channel in channels) |
| try { |
| channel.cancel(cause) |
| } catch (e: Throwable) { |
| if (exception == null) { |
| exception = e |
| } else { |
| exception.addSuppressedThrowable(e) |
| } |
| } |
| exception?.let { throw it } |
| } |
| |
| /** |
| * Makes sure that the given [block] consumes all elements from the given channel |
| * by always invoking [cancel][ReceiveChannel.cancel] after the execution of the block. |
| * |
| * **WARNING**: It is planned that in the future a second invocation of this method |
| * on an channel that is already being consumed is going to fail fast, that is |
| * immediately throw an [IllegalStateException]. |
| * See [this issue](https://github.com/Kotlin/kotlinx.coroutines/issues/167) |
| * for details. |
| * |
| * The operation is _terminal_. |
| */ |
| public inline fun <E, R> ReceiveChannel<E>.consume(block: ReceiveChannel<E>.() -> R): R { |
| var cause: Throwable? = null |
| try { |
| return block() |
| } catch (e: Throwable) { |
| cause = e |
| throw e |
| } finally { |
| cancel(cause) |
| } |
| } |
| |
| /** |
| * Performs the given [action] for each received element. |
| * |
| * **WARNING**: It is planned that in the future a second invocation of this method |
| * on an channel that is already being consumed is going to fail fast, that is |
| * immediately throw an [IllegalStateException]. |
| * See [this issue](https://github.com/Kotlin/kotlinx.coroutines/issues/167) |
| * for details. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E> ReceiveChannel<E>.consumeEach(action: (E) -> Unit) = |
| consume { |
| for (e in this) action(e) |
| } |
| |
| /** |
| * @suppress: **Deprecated**: binary compatibility with old code |
| */ |
| @Deprecated("binary compatibility with old code", level = DeprecationLevel.HIDDEN) |
| public suspend fun <E> ReceiveChannel<E>.consumeEach(action: suspend (E) -> Unit) = |
| consumeEach { action(it) } |
| |
| /** |
| * Performs the given [action] for each received element. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E> ReceiveChannel<E>.consumeEachIndexed(action: (IndexedValue<E>) -> Unit) { |
| var index = 0 |
| consumeEach { |
| action(IndexedValue(index++, it)) |
| } |
| } |
| |
| /** |
| * Returns an element at the given [index] or throws an [IndexOutOfBoundsException] if the [index] is out of bounds of this channel. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend fun <E> ReceiveChannel<E>.elementAt(index: Int): E = |
| elementAtOrElse(index) { throw IndexOutOfBoundsException("ReceiveChannel doesn't contain element at index $index.") } |
| |
| /** |
| * Returns an element at the given [index] or the result of calling the [defaultValue] function if the [index] is out of bounds of this channel. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E> ReceiveChannel<E>.elementAtOrElse(index: Int, defaultValue: (Int) -> E): E = |
| consume { |
| if (index < 0) |
| return defaultValue(index) |
| var count = 0 |
| for (element in this) { |
| if (index == count++) |
| return element |
| } |
| return defaultValue(index) |
| } |
| |
| /** |
| * Returns an element at the given [index] or `null` if the [index] is out of bounds of this channel. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend fun <E> ReceiveChannel<E>.elementAtOrNull(index: Int): E? = |
| consume { |
| if (index < 0) |
| return null |
| var count = 0 |
| for (element in this) { |
| if (index == count++) |
| return element |
| } |
| return null |
| } |
| |
| /** |
| * Returns the first element matching the given [predicate], or `null` if no such element was found. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E> ReceiveChannel<E>.find(predicate: (E) -> Boolean): E? = |
| firstOrNull(predicate) |
| |
| /** |
| * Returns the last element matching the given [predicate], or `null` if no such element was found. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E> ReceiveChannel<E>.findLast(predicate: (E) -> Boolean): E? = |
| lastOrNull(predicate) |
| |
| /** |
| * Returns first element. |
| * @throws [NoSuchElementException] if the channel is empty. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend fun <E> ReceiveChannel<E>.first(): E = |
| consume { |
| val iterator = iterator() |
| if (!iterator.hasNext()) |
| throw NoSuchElementException("ReceiveChannel is empty.") |
| return iterator.next() |
| } |
| |
| /** |
| * Returns the first element matching the given [predicate]. |
| * @throws [NoSuchElementException] if no such element is found. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E> ReceiveChannel<E>.first(predicate: (E) -> Boolean): E { |
| consumeEach { |
| if (predicate(it)) return it |
| } |
| throw NoSuchElementException("ReceiveChannel contains no element matching the predicate.") |
| } |
| |
| /** |
| * Returns the first element, or `null` if the channel is empty. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend fun <E> ReceiveChannel<E>.firstOrNull(): E? = |
| consume { |
| val iterator = iterator() |
| if (!iterator.hasNext()) |
| return null |
| return iterator.next() |
| } |
| |
| /** |
| * Returns the first element matching the given [predicate], or `null` if element was not found. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public inline suspend fun <E> ReceiveChannel<E>.firstOrNull(predicate: (E) -> Boolean): E? { |
| consumeEach { |
| if (predicate(it)) return it |
| } |
| return null |
| } |
| |
| /** |
| * Returns first index of [element], or -1 if the channel does not contain element. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend fun <E> ReceiveChannel<E>.indexOf(element: E): Int { |
| var index = 0 |
| consumeEach { |
| if (element == it) |
| return index |
| index++ |
| } |
| return -1 |
| } |
| |
| /** |
| * Returns index of the first element matching the given [predicate], or -1 if the channel does not contain such element. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E> ReceiveChannel<E>.indexOfFirst(predicate: (E) -> Boolean): Int { |
| var index = 0 |
| consumeEach { |
| if (predicate(it)) |
| return index |
| index++ |
| } |
| return -1 |
| } |
| |
| /** |
| * Returns index of the last element matching the given [predicate], or -1 if the channel does not contain such element. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public inline suspend fun <E> ReceiveChannel<E>.indexOfLast(predicate: (E) -> Boolean): Int { |
| var lastIndex = -1 |
| var index = 0 |
| consumeEach { |
| if (predicate(it)) |
| lastIndex = index |
| index++ |
| } |
| return lastIndex |
| } |
| |
| /** |
| * Returns the last element. |
| * @throws [NoSuchElementException] if the channel is empty. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend fun <E> ReceiveChannel<E>.last(): E = |
| consume { |
| val iterator = iterator() |
| if (!iterator.hasNext()) |
| throw NoSuchElementException("ReceiveChannel is empty.") |
| var last = iterator.next() |
| while (iterator.hasNext()) |
| last = iterator.next() |
| return last |
| } |
| |
| /** |
| * Returns the last element matching the given [predicate]. |
| * @throws [NoSuchElementException] if no such element is found. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E> ReceiveChannel<E>.last(predicate: (E) -> Boolean): E { |
| var last: E? = null |
| var found = false |
| consumeEach { |
| if (predicate(it)) { |
| last = it |
| found = true |
| } |
| } |
| if (!found) throw NoSuchElementException("ReceiveChannel contains no element matching the predicate.") |
| @Suppress("UNCHECKED_CAST") |
| return last as E |
| } |
| |
| /** |
| * Returns last index of [element], or -1 if the channel does not contain element. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend fun <E> ReceiveChannel<E>.lastIndexOf(element: E): Int { |
| var lastIndex = -1 |
| var index = 0 |
| consumeEach { |
| if (element == it) |
| lastIndex = index |
| index++ |
| } |
| return lastIndex |
| } |
| |
| /** |
| * Returns the last element, or `null` if the channel is empty. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend fun <E> ReceiveChannel<E>.lastOrNull(): E? = |
| consume { |
| val iterator = iterator() |
| if (!iterator.hasNext()) |
| return null |
| var last = iterator.next() |
| while (iterator.hasNext()) |
| last = iterator.next() |
| return last |
| } |
| |
| /** |
| * Returns the last element matching the given [predicate], or `null` if no such element was found. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E> ReceiveChannel<E>.lastOrNull(predicate: (E) -> Boolean): E? { |
| var last: E? = null |
| consumeEach { |
| if (predicate(it)) { |
| last = it |
| } |
| } |
| return last |
| } |
| |
| /** |
| * Returns the single element, or throws an exception if the channel is empty or has more than one element. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend fun <E> ReceiveChannel<E>.single(): E = |
| consume { |
| val iterator = iterator() |
| if (!iterator.hasNext()) |
| throw NoSuchElementException("ReceiveChannel is empty.") |
| val single = iterator.next() |
| if (iterator.hasNext()) |
| throw IllegalArgumentException("ReceiveChannel has more than one element.") |
| return single |
| } |
| |
| /** |
| * Returns the single element matching the given [predicate], or throws exception if there is no or more than one matching element. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E> ReceiveChannel<E>.single(predicate: (E) -> Boolean): E { |
| var single: E? = null |
| var found = false |
| consumeEach { |
| if (predicate(it)) { |
| if (found) throw IllegalArgumentException("ReceiveChannel contains more than one matching element.") |
| single = it |
| found = true |
| } |
| } |
| if (!found) throw NoSuchElementException("ReceiveChannel contains no element matching the predicate.") |
| @Suppress("UNCHECKED_CAST") |
| return single as E |
| } |
| |
| /** |
| * Returns single element, or `null` if the channel is empty or has more than one element. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend fun <E> ReceiveChannel<E>.singleOrNull(): E? = |
| consume { |
| val iterator = iterator() |
| if (!iterator.hasNext()) |
| return null |
| val single = iterator.next() |
| if (iterator.hasNext()) |
| return null |
| return single |
| } |
| |
| /** |
| * Returns the single element matching the given [predicate], or `null` if element was not found or more than one element was found. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E> ReceiveChannel<E>.singleOrNull(predicate: (E) -> Boolean): E? { |
| var single: E? = null |
| var found = false |
| consumeEach { |
| if (predicate(it)) { |
| if (found) return null |
| single = it |
| found = true |
| } |
| } |
| if (!found) return null |
| return single |
| } |
| |
| /** |
| * Returns a channel containing all elements except first [n] elements. |
| * |
| * The operation is _intermediate_ and _stateless_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public fun <E> ReceiveChannel<E>.drop(n: Int, context: CoroutineContext = Unconfined): ReceiveChannel<E> = |
| produce(context, onCompletion = consumes()) { |
| require(n >= 0) { "Requested element count $n is less than zero." } |
| var remaining: Int = n |
| if (remaining > 0) |
| for (e in this@drop) { |
| remaining-- |
| if (remaining == 0) |
| break |
| } |
| for (e in this@drop) { |
| send(e) |
| } |
| } |
| |
| /** |
| * Returns a channel containing all elements except first elements that satisfy the given [predicate]. |
| * |
| * The operation is _intermediate_ and _stateless_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| // todo: mark predicate with crossinline modifier when it is supported: https://youtrack.jetbrains.com/issue/KT-19159 |
| public fun <E> ReceiveChannel<E>.dropWhile(context: CoroutineContext = Unconfined, predicate: suspend (E) -> Boolean): ReceiveChannel<E> = |
| produce(context, onCompletion = consumes()) { |
| for (e in this@dropWhile) { |
| if (!predicate(e)) { |
| send(e) |
| break |
| } |
| } |
| for (e in this@dropWhile) { |
| send(e) |
| } |
| } |
| |
| /** |
| * Returns a channel containing only elements matching the given [predicate]. |
| * |
| * The operation is _intermediate_ and _stateless_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| // todo: mark predicate with crossinline modifier when it is supported: https://youtrack.jetbrains.com/issue/KT-19159 |
| public fun <E> ReceiveChannel<E>.filter(context: CoroutineContext = Unconfined, predicate: suspend (E) -> Boolean): ReceiveChannel<E> = |
| produce(context, onCompletion = consumes()) { |
| for (e in this@filter) { |
| if (predicate(e)) send(e) |
| } |
| } |
| |
| /** |
| * Returns a channel containing only elements matching the given [predicate]. |
| * @param [predicate] function that takes the index of an element and the element itself |
| * and returns the result of predicate evaluation on the element. |
| * |
| * The operation is _intermediate_ and _stateless_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| // todo: mark predicate with crossinline modifier when it is supported: https://youtrack.jetbrains.com/issue/KT-19159 |
| public fun <E> ReceiveChannel<E>.filterIndexed(context: CoroutineContext = Unconfined, predicate: suspend (index: Int, E) -> Boolean): ReceiveChannel<E> = |
| produce(context, onCompletion = consumes()) { |
| var index = 0 |
| for (e in this@filterIndexed) { |
| if (predicate(index++, e)) send(e) |
| } |
| } |
| |
| /** |
| * Appends all elements matching the given [predicate] to the given [destination]. |
| * @param [predicate] function that takes the index of an element and the element itself |
| * and returns the result of predicate evaluation on the element. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E, C : MutableCollection<in E>> ReceiveChannel<E>.filterIndexedTo(destination: C, predicate: (index: Int, E) -> Boolean): C { |
| consumeEachIndexed { (index, element) -> |
| if (predicate(index, element)) destination.add(element) |
| } |
| return destination |
| } |
| |
| /** |
| * Appends all elements matching the given [predicate] to the given [destination]. |
| * @param [predicate] function that takes the index of an element and the element itself |
| * and returns the result of predicate evaluation on the element. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E, C : SendChannel<E>> ReceiveChannel<E>.filterIndexedTo(destination: C, predicate: (index: Int, E) -> Boolean): C { |
| consumeEachIndexed { (index, element) -> |
| if (predicate(index, element)) destination.send(element) |
| } |
| return destination |
| } |
| |
| /** |
| * Returns a channel containing all elements not matching the given [predicate]. |
| * |
| * The operation is _intermediate_ and _stateless_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| // todo: mark predicate with crossinline modifier when it is supported: https://youtrack.jetbrains.com/issue/KT-19159 |
| public fun <E> ReceiveChannel<E>.filterNot(context: CoroutineContext = Unconfined, predicate: suspend (E) -> Boolean): ReceiveChannel<E> = |
| filter(context) { !predicate(it) } |
| |
| /** |
| * @suppress **Deprecated**: For binary compatibility only |
| */ |
| @Deprecated("For binary compatibility only", level = DeprecationLevel.HIDDEN) |
| public fun <E> ReceiveChannel<E>.filterNot(predicate: suspend (E) -> Boolean): ReceiveChannel<E> = filterNot(predicate = predicate) |
| |
| /** |
| * Returns a channel containing all elements that are not `null`. |
| * |
| * The operation is _intermediate_ and _stateless_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| @Suppress("UNCHECKED_CAST") |
| public fun <E : Any> ReceiveChannel<E?>.filterNotNull(): ReceiveChannel<E> = |
| filter { it != null } as ReceiveChannel<E> |
| |
| /** |
| * Appends all elements that are not `null` to the given [destination]. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend fun <E : Any, C : MutableCollection<in E>> ReceiveChannel<E?>.filterNotNullTo(destination: C): C { |
| consumeEach { |
| if (it != null) destination.add(it) |
| } |
| return destination |
| } |
| |
| /** |
| * Appends all elements that are not `null` to the given [destination]. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend fun <E : Any, C : SendChannel<E>> ReceiveChannel<E?>.filterNotNullTo(destination: C): C { |
| consumeEach { |
| if (it != null) destination.send(it) |
| } |
| return destination |
| } |
| |
| /** |
| * Appends all elements not matching the given [predicate] to the given [destination]. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E, C : MutableCollection<in E>> ReceiveChannel<E>.filterNotTo(destination: C, predicate: (E) -> Boolean): C { |
| consumeEach { |
| if (!predicate(it)) destination.add(it) |
| } |
| return destination |
| } |
| |
| /** |
| * Appends all elements not matching the given [predicate] to the given [destination]. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E, C : SendChannel<E>> ReceiveChannel<E>.filterNotTo(destination: C, predicate: (E) -> Boolean): C { |
| consumeEach { |
| if (!predicate(it)) destination.send(it) |
| } |
| return destination |
| } |
| |
| /** |
| * Appends all elements matching the given [predicate] to the given [destination]. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E, C : MutableCollection<in E>> ReceiveChannel<E>.filterTo(destination: C, predicate: (E) -> Boolean): C { |
| consumeEach { |
| if (predicate(it)) destination.add(it) |
| } |
| return destination |
| } |
| |
| /** |
| * Appends all elements matching the given [predicate] to the given [destination]. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E, C : SendChannel<E>> ReceiveChannel<E>.filterTo(destination: C, predicate: (E) -> Boolean): C { |
| consumeEach { |
| if (predicate(it)) destination.send(it) |
| } |
| return destination |
| } |
| |
| /** |
| * Returns a channel containing first [n] elements. |
| * |
| * The operation is _intermediate_ and _stateless_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public fun <E> ReceiveChannel<E>.take(n: Int, context: CoroutineContext = Unconfined): ReceiveChannel<E> = |
| produce(context, onCompletion = consumes()) { |
| if (n == 0) return@produce |
| require(n >= 0) { "Requested element count $n is less than zero." } |
| var remaining: Int = n |
| for (e in this@take) { |
| send(e) |
| remaining-- |
| if (remaining == 0) |
| return@produce |
| } |
| } |
| |
| /** |
| * Returns a channel containing first elements satisfying the given [predicate]. |
| * |
| * The operation is _intermediate_ and _stateless_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| // todo: mark predicate with crossinline modifier when it is supported: https://youtrack.jetbrains.com/issue/KT-19159 |
| public fun <E> ReceiveChannel<E>.takeWhile(context: CoroutineContext = Unconfined, predicate: suspend (E) -> Boolean): ReceiveChannel<E> = |
| produce(context, onCompletion = consumes()) { |
| for (e in this@takeWhile) { |
| if (!predicate(e)) return@produce |
| send(e) |
| } |
| } |
| |
| /** |
| * Returns a [Map] containing key-value pairs provided by [transform] function |
| * applied to elements of the given channel. |
| * |
| * If any of two pairs would have the same key the last one gets added to the map. |
| * |
| * The returned map preserves the entry iteration order of the original channel. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E, K, V> ReceiveChannel<E>.associate(transform: (E) -> Pair<K, V>): Map<K, V> = |
| associateTo(LinkedHashMap(), transform) |
| |
| /** |
| * Returns a [Map] containing the elements from the given channel indexed by the key |
| * returned from [keySelector] function applied to each element. |
| * |
| * If any two elements would have the same key returned by [keySelector] the last one gets added to the map. |
| * |
| * The returned map preserves the entry iteration order of the original channel. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E, K> ReceiveChannel<E>.associateBy(keySelector: (E) -> K): Map<K, E> = |
| associateByTo(LinkedHashMap(), keySelector) |
| |
| /** |
| * Returns a [Map] containing the values provided by [valueTransform] and indexed by [keySelector] functions applied to elements of the given channel. |
| * |
| * If any two elements would have the same key returned by [keySelector] the last one gets added to the map. |
| * |
| * The returned map preserves the entry iteration order of the original channel. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E, K, V> ReceiveChannel<E>.associateBy(keySelector: (E) -> K, valueTransform: (E) -> V): Map<K, V> = |
| associateByTo(LinkedHashMap(), keySelector, valueTransform) |
| |
| /** |
| * Populates and returns the [destination] mutable map with key-value pairs, |
| * where key is provided by the [keySelector] function applied to each element of the given channel |
| * and value is the element itself. |
| * |
| * If any two elements would have the same key returned by [keySelector] the last one gets added to the map. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E, K, M : MutableMap<in K, in E>> ReceiveChannel<E>.associateByTo(destination: M, keySelector: (E) -> K): M { |
| consumeEach { |
| destination.put(keySelector(it), it) |
| } |
| return destination |
| } |
| |
| /** |
| * Populates and returns the [destination] mutable map with key-value pairs, |
| * where key is provided by the [keySelector] function and |
| * and value is provided by the [valueTransform] function applied to elements of the given channel. |
| * |
| * If any two elements would have the same key returned by [keySelector] the last one gets added to the map. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E, K, V, M : MutableMap<in K, in V>> ReceiveChannel<E>.associateByTo(destination: M, keySelector: (E) -> K, valueTransform: (E) -> V): M { |
| consumeEach { |
| destination.put(keySelector(it), valueTransform(it)) |
| } |
| return destination |
| } |
| |
| /** |
| * Populates and returns the [destination] mutable map with key-value pairs |
| * provided by [transform] function applied to each element of the given channel. |
| * |
| * If any of two pairs would have the same key the last one gets added to the map. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E, K, V, M : MutableMap<in K, in V>> ReceiveChannel<E>.associateTo(destination: M, transform: (E) -> Pair<K, V>): M { |
| consumeEach { |
| destination += transform(it) |
| } |
| return destination |
| } |
| |
| /** |
| * Send each element of the original channel |
| * and appends the results to the given [destination]. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend fun <E, C : SendChannel<E>> ReceiveChannel<E>.toChannel(destination: C): C { |
| consumeEach { |
| destination.send(it) |
| } |
| return destination |
| } |
| |
| /** |
| * Appends all elements to the given [destination] collection. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend fun <E, C : MutableCollection<in E>> ReceiveChannel<E>.toCollection(destination: C): C { |
| consumeEach { |
| destination.add(it) |
| } |
| return destination |
| } |
| |
| /** |
| * Returns a [List] containing all elements. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend fun <E> ReceiveChannel<E>.toList(): List<E> = |
| this.toMutableList() |
| |
| /** |
| * Returns a [Map] filled with all elements of this channel. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend fun <K, V> ReceiveChannel<Pair<K, V>>.toMap(): Map<K, V> = |
| toMap(LinkedHashMap()) |
| |
| /** |
| * Returns a [MutableMap] filled with all elements of this channel. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend fun <K, V, M : MutableMap<in K, in V>> ReceiveChannel<Pair<K, V>>.toMap(destination: M): M { |
| consumeEach { |
| destination += it |
| } |
| return destination |
| } |
| |
| /** |
| * Returns a [MutableList] filled with all elements of this channel. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend fun <E> ReceiveChannel<E>.toMutableList(): MutableList<E> = |
| toCollection(ArrayList()) |
| |
| /** |
| * Returns a [Set] of all elements. |
| * |
| * The returned set preserves the element iteration order of the original channel. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend fun <E> ReceiveChannel<E>.toSet(): Set<E> = |
| this.toMutableSet() |
| |
| /** |
| * Returns a single channel of all elements from results of [transform] function being invoked on each element of original channel. |
| * |
| * The operation is _intermediate_ and _stateless_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| // todo: mark predicate with crossinline modifier when it is supported: https://youtrack.jetbrains.com/issue/KT-19159 |
| public fun <E, R> ReceiveChannel<E>.flatMap(context: CoroutineContext = Unconfined, transform: suspend (E) -> ReceiveChannel<R>): ReceiveChannel<R> = |
| produce(context, onCompletion = consumes()) { |
| for (e in this@flatMap) { |
| transform(e).toChannel(this) |
| } |
| } |
| |
| /** |
| * Groups elements of the original channel by the key returned by the given [keySelector] function |
| * applied to each element and returns a map where each group key is associated with a list of corresponding elements. |
| * |
| * The returned map preserves the entry iteration order of the keys produced from the original channel. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E, K> ReceiveChannel<E>.groupBy(keySelector: (E) -> K): Map<K, List<E>> = |
| groupByTo(LinkedHashMap(), keySelector) |
| |
| /** |
| * Groups values returned by the [valueTransform] function applied to each element of the original channel |
| * by the key returned by the given [keySelector] function applied to the element |
| * and returns a map where each group key is associated with a list of corresponding values. |
| * |
| * The returned map preserves the entry iteration order of the keys produced from the original channel. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E, K, V> ReceiveChannel<E>.groupBy(keySelector: (E) -> K, valueTransform: (E) -> V): Map<K, List<V>> = |
| groupByTo(LinkedHashMap(), keySelector, valueTransform) |
| |
| /** |
| * Groups elements of the original channel by the key returned by the given [keySelector] function |
| * applied to each element and puts to the [destination] map each group key associated with a list of corresponding elements. |
| * |
| * @return The [destination] map. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E, K, M : MutableMap<in K, MutableList<E>>> ReceiveChannel<E>.groupByTo(destination: M, keySelector: (E) -> K): M { |
| consumeEach { |
| val key = keySelector(it) |
| val list = destination.getOrPut(key) { ArrayList() } |
| list.add(it) |
| } |
| return destination |
| } |
| |
| /** |
| * Groups values returned by the [valueTransform] function applied to each element of the original channel |
| * by the key returned by the given [keySelector] function applied to the element |
| * and puts to the [destination] map each group key associated with a list of corresponding values. |
| * |
| * @return The [destination] map. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E, K, V, M : MutableMap<in K, MutableList<V>>> ReceiveChannel<E>.groupByTo(destination: M, keySelector: (E) -> K, valueTransform: (E) -> V): M { |
| consumeEach { |
| val key = keySelector(it) |
| val list = destination.getOrPut(key) { ArrayList() } |
| list.add(valueTransform(it)) |
| } |
| return destination |
| } |
| |
| /** |
| * Returns a channel containing the results of applying the given [transform] function |
| * to each element in the original channel. |
| * |
| * The operation is _intermediate_ and _stateless_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| // todo: mark transform with crossinline modifier when it is supported: https://youtrack.jetbrains.com/issue/KT-19159 |
| public fun <E, R> ReceiveChannel<E>.map(context: CoroutineContext = Unconfined, transform: suspend (E) -> R): ReceiveChannel<R> = |
| produce(context, onCompletion = consumes()) { |
| consumeEach { |
| send(transform(it)) |
| } |
| } |
| |
| /** |
| * Returns a channel containing the results of applying the given [transform] function |
| * to each element and its index in the original channel. |
| * @param [transform] function that takes the index of an element and the element itself |
| * and returns the result of the transform applied to the element. |
| * |
| * The operation is _intermediate_ and _stateless_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| // todo: mark predicate with crossinline modifier when it is supported: https://youtrack.jetbrains.com/issue/KT-19159 |
| public fun <E, R> ReceiveChannel<E>.mapIndexed(context: CoroutineContext = Unconfined, transform: suspend (index: Int, E) -> R): ReceiveChannel<R> = |
| produce(context, onCompletion = consumes()) { |
| var index = 0 |
| for (e in this@mapIndexed) { |
| send(transform(index++, e)) |
| } |
| } |
| |
| /** |
| * Returns a channel containing only the non-null results of applying the given [transform] function |
| * to each element and its index in the original channel. |
| * @param [transform] function that takes the index of an element and the element itself |
| * and returns the result of the transform applied to the element. |
| * |
| * The operation is _intermediate_ and _stateless_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| // todo: mark predicate with crossinline modifier when it is supported: https://youtrack.jetbrains.com/issue/KT-19159 |
| public fun <E, R : Any> ReceiveChannel<E>.mapIndexedNotNull(context: CoroutineContext = Unconfined, transform: suspend (index: Int, E) -> R?): ReceiveChannel<R> = |
| mapIndexed(context, transform).filterNotNull() |
| |
| /** |
| * Applies the given [transform] function to each element and its index in the original channel |
| * and appends only the non-null results to the given [destination]. |
| * @param [transform] function that takes the index of an element and the element itself |
| * and returns the result of the transform applied to the element. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E, R : Any, C : MutableCollection<in R>> ReceiveChannel<E>.mapIndexedNotNullTo(destination: C, transform: (index: Int, E) -> R?): C { |
| consumeEachIndexed { (index, element) -> |
| transform(index, element)?.let { destination.add(it) } |
| } |
| return destination |
| } |
| |
| /** |
| * Applies the given [transform] function to each element and its index in the original channel |
| * and appends only the non-null results to the given [destination]. |
| * @param [transform] function that takes the index of an element and the element itself |
| * and returns the result of the transform applied to the element. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E, R : Any, C : SendChannel<R>> ReceiveChannel<E>.mapIndexedNotNullTo(destination: C, transform: (index: Int, E) -> R?): C { |
| consumeEachIndexed { (index, element) -> |
| transform(index, element)?.let { destination.send(it) } |
| } |
| return destination |
| } |
| |
| /** |
| * Applies the given [transform] function to each element and its index in the original channel |
| * and appends the results to the given [destination]. |
| * @param [transform] function that takes the index of an element and the element itself |
| * and returns the result of the transform applied to the element. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E, R, C : MutableCollection<in R>> ReceiveChannel<E>.mapIndexedTo(destination: C, transform: (index: Int, E) -> R): C { |
| var index = 0 |
| consumeEach { |
| destination.add(transform(index++, it)) |
| } |
| return destination |
| } |
| |
| /** |
| * Applies the given [transform] function to each element and its index in the original channel |
| * and appends the results to the given [destination]. |
| * @param [transform] function that takes the index of an element and the element itself |
| * and returns the result of the transform applied to the element. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E, R, C : SendChannel<R>> ReceiveChannel<E>.mapIndexedTo(destination: C, transform: (index: Int, E) -> R): C { |
| var index = 0 |
| consumeEach { |
| destination.send(transform(index++, it)) |
| } |
| return destination |
| } |
| |
| /** |
| * Returns a channel containing only the non-null results of applying the given [transform] function |
| * to each element in the original channel. |
| * |
| * The operation is _intermediate_ and _stateless_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| // todo: mark predicate with crossinline modifier when it is supported: https://youtrack.jetbrains.com/issue/KT-19159 |
| public fun <E, R : Any> ReceiveChannel<E>.mapNotNull(context: CoroutineContext = Unconfined, transform: suspend (E) -> R?): ReceiveChannel<R> = |
| map(context, transform).filterNotNull() |
| |
| /** |
| * Applies the given [transform] function to each element in the original channel |
| * and appends only the non-null results to the given [destination]. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E, R : Any, C : MutableCollection<in R>> ReceiveChannel<E>.mapNotNullTo(destination: C, transform: (E) -> R?): C { |
| consumeEach { |
| transform(it)?.let { destination.add(it) } |
| } |
| return destination |
| } |
| |
| /** |
| * Applies the given [transform] function to each element in the original channel |
| * and appends only the non-null results to the given [destination]. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E, R : Any, C : SendChannel<R>> ReceiveChannel<E>.mapNotNullTo(destination: C, transform: (E) -> R?): C { |
| consumeEach { |
| transform(it)?.let { destination.send(it) } |
| } |
| return destination |
| } |
| |
| /** |
| * Applies the given [transform] function to each element of the original channel |
| * and appends the results to the given [destination]. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E, R, C : MutableCollection<in R>> ReceiveChannel<E>.mapTo(destination: C, transform: (E) -> R): C { |
| consumeEach { |
| destination.add(transform(it)) |
| } |
| return destination |
| } |
| |
| /** |
| * Applies the given [transform] function to each element of the original channel |
| * and appends the results to the given [destination]. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E, R, C : SendChannel<R>> ReceiveChannel<E>.mapTo(destination: C, transform: (E) -> R): C { |
| consumeEach { |
| destination.send(transform(it)) |
| } |
| return destination |
| } |
| |
| /** |
| * Returns a channel of [IndexedValue] for each element of the original channel. |
| * |
| * The operation is _intermediate_ and _stateless_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public fun <E> ReceiveChannel<E>.withIndex(context: CoroutineContext = Unconfined): ReceiveChannel<IndexedValue<E>> = |
| produce(context, onCompletion = consumes()) { |
| var index = 0 |
| for (e in this@withIndex) { |
| send(IndexedValue(index++, e)) |
| } |
| } |
| |
| /** |
| * Returns a channel containing only distinct elements from the given channel. |
| * |
| * The elements in the resulting channel are in the same order as they were in the source channel. |
| * |
| * The operation is _intermediate_ and _stateful_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public fun <E> ReceiveChannel<E>.distinct(): ReceiveChannel<E> = |
| this.distinctBy { it } |
| |
| /** |
| * Returns a channel containing only elements from the given channel |
| * having distinct keys returned by the given [selector] function. |
| * |
| * The elements in the resulting channel are in the same order as they were in the source channel. |
| * |
| * The operation is _intermediate_ and _stateful_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| // todo: mark predicate with crossinline modifier when it is supported: https://youtrack.jetbrains.com/issue/KT-19159 |
| public fun <E, K> ReceiveChannel<E>.distinctBy(context: CoroutineContext = Unconfined, selector: suspend (E) -> K): ReceiveChannel<E> = |
| produce(context, onCompletion = consumes()) { |
| val keys = HashSet<K>() |
| for (e in this@distinctBy) { |
| val k = selector(e) |
| if (k !in keys) { |
| send(e) |
| keys += k |
| } |
| } |
| } |
| |
| /** |
| * Returns a mutable set containing all distinct elements from the given channel. |
| * |
| * The returned set preserves the element iteration order of the original channel. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend fun <E> ReceiveChannel<E>.toMutableSet(): MutableSet<E> = |
| toCollection(LinkedHashSet()) |
| |
| /** |
| * Returns `true` if all elements match the given [predicate]. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E> ReceiveChannel<E>.all(predicate: (E) -> Boolean): Boolean { |
| consumeEach { |
| if (!predicate(it)) return false |
| } |
| return true |
| } |
| |
| /** |
| * Returns `true` if channel has at least one element. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend fun <E> ReceiveChannel<E>.any(): Boolean = |
| consume { |
| return iterator().hasNext() |
| } |
| |
| /** |
| * Returns `true` if at least one element matches the given [predicate]. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E> ReceiveChannel<E>.any(predicate: (E) -> Boolean): Boolean { |
| consumeEach { |
| if (predicate(it)) return true |
| } |
| return false |
| } |
| |
| /** |
| * Returns the number of elements in this channel. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend fun <E> ReceiveChannel<E>.count(): Int { |
| var count = 0 |
| consumeEach { count++ } |
| return count |
| } |
| |
| /** |
| * Returns the number of elements matching the given [predicate]. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E> ReceiveChannel<E>.count(predicate: (E) -> Boolean): Int { |
| var count = 0 |
| consumeEach { |
| if (predicate(it)) count++ |
| } |
| return count |
| } |
| |
| /** |
| * Accumulates value starting with [initial] value and applying [operation] from left to right to current accumulator value and each element. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E, R> ReceiveChannel<E>.fold(initial: R, operation: (acc: R, E) -> R): R { |
| var accumulator = initial |
| consumeEach { |
| accumulator = operation(accumulator, it) |
| } |
| return accumulator |
| } |
| |
| /** |
| * Accumulates value starting with [initial] value and applying [operation] from left to right |
| * to current accumulator value and each element with its index in the original channel. |
| * @param [operation] function that takes the index of an element, current accumulator value |
| * and the element itself, and calculates the next accumulator value. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E, R> ReceiveChannel<E>.foldIndexed(initial: R, operation: (index: Int, acc: R, E) -> R): R { |
| var index = 0 |
| var accumulator = initial |
| consumeEach { |
| accumulator = operation(index++, accumulator, it) |
| } |
| return accumulator |
| } |
| |
| /** |
| * Returns the first element yielding the largest value of the given function or `null` if there are no elements. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E, R : Comparable<R>> ReceiveChannel<E>.maxBy(selector: (E) -> R): E? = |
| consume { |
| val iterator = iterator() |
| if (!iterator.hasNext()) return null |
| var maxElem = iterator.next() |
| var maxValue = selector(maxElem) |
| while (iterator.hasNext()) { |
| val e = iterator.next() |
| val v = selector(e) |
| if (maxValue < v) { |
| maxElem = e |
| maxValue = v |
| } |
| } |
| return maxElem |
| } |
| |
| /** |
| * Returns the first element having the largest value according to the provided [comparator] or `null` if there are no elements. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend fun <E> ReceiveChannel<E>.maxWith(comparator: Comparator<in E>): E? = |
| consume { |
| val iterator = iterator() |
| if (!iterator.hasNext()) return null |
| var max = iterator.next() |
| while (iterator.hasNext()) { |
| val e = iterator.next() |
| if (comparator.compare(max, e) < 0) max = e |
| } |
| return max |
| } |
| |
| /** |
| * Returns the first element yielding the smallest value of the given function or `null` if there are no elements. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E, R : Comparable<R>> ReceiveChannel<E>.minBy(selector: (E) -> R): E? = |
| consume { |
| val iterator = iterator() |
| if (!iterator.hasNext()) return null |
| var minElem = iterator.next() |
| var minValue = selector(minElem) |
| while (iterator.hasNext()) { |
| val e = iterator.next() |
| val v = selector(e) |
| if (minValue > v) { |
| minElem = e |
| minValue = v |
| } |
| } |
| return minElem |
| } |
| |
| /** |
| * Returns the first element having the smallest value according to the provided [comparator] or `null` if there are no elements. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend fun <E> ReceiveChannel<E>.minWith(comparator: Comparator<in E>): E? = |
| consume { |
| val iterator = iterator() |
| if (!iterator.hasNext()) return null |
| var min = iterator.next() |
| while (iterator.hasNext()) { |
| val e = iterator.next() |
| if (comparator.compare(min, e) > 0) min = e |
| } |
| return min |
| } |
| |
| /** |
| * Returns `true` if the channel has no elements. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend fun <E> ReceiveChannel<E>.none(): Boolean = |
| consume { |
| return !iterator().hasNext() |
| } |
| |
| /** |
| * Returns `true` if no elements match the given [predicate]. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E> ReceiveChannel<E>.none(predicate: (E) -> Boolean): Boolean { |
| consumeEach { |
| if (predicate(it)) return false |
| } |
| return true |
| } |
| |
| /** |
| * Accumulates value starting with the first element and applying [operation] from left to right to current accumulator value and each element. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <S, E : S> ReceiveChannel<E>.reduce(operation: (acc: S, E) -> S): S = |
| consume { |
| val iterator = this.iterator() |
| if (!iterator.hasNext()) throw UnsupportedOperationException("Empty channel can't be reduced.") |
| var accumulator: S = iterator.next() |
| while (iterator.hasNext()) { |
| accumulator = operation(accumulator, iterator.next()) |
| } |
| return accumulator |
| } |
| |
| /** |
| * Accumulates value starting with the first element and applying [operation] from left to right |
| * to current accumulator value and each element with its index in the original channel. |
| * @param [operation] function that takes the index of an element, current accumulator value |
| * and the element itself and calculates the next accumulator value. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| // todo: mark operation with crossinline modifier when it is supported: https://youtrack.jetbrains.com/issue/KT-19159 |
| public suspend inline fun <S, E : S> ReceiveChannel<E>.reduceIndexed(operation: (index: Int, acc: S, E) -> S): S = |
| consume { |
| val iterator = this.iterator() |
| if (!iterator.hasNext()) throw UnsupportedOperationException("Empty channel can't be reduced.") |
| var index = 1 |
| var accumulator: S = iterator.next() |
| while (iterator.hasNext()) { |
| accumulator = operation(index++, accumulator, iterator.next()) |
| } |
| return accumulator |
| } |
| |
| /** |
| * Returns the sum of all values produced by [selector] function applied to each element in the channel. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E> ReceiveChannel<E>.sumBy(selector: (E) -> Int): Int { |
| var sum = 0 |
| consumeEach { |
| sum += selector(it) |
| } |
| return sum |
| } |
| |
| /** |
| * Returns the sum of all values produced by [selector] function applied to each element in the channel. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E> ReceiveChannel<E>.sumByDouble(selector: (E) -> Double): Double { |
| var sum = 0.0 |
| consumeEach { |
| sum += selector(it) |
| } |
| return sum |
| } |
| |
| /** |
| * Returns an original collection containing all the non-`null` elements, throwing an [IllegalArgumentException] if there are any `null` elements. |
| * |
| * The operation is _intermediate_ and _stateless_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public fun <E : Any> ReceiveChannel<E?>.requireNoNulls(): ReceiveChannel<E> = |
| map { it ?: throw IllegalArgumentException("null element found in $this.") } |
| |
| /** |
| * Splits the original channel into pair of lists, |
| * where *first* list contains elements for which [predicate] yielded `true`, |
| * while *second* list contains elements for which [predicate] yielded `false`. |
| * |
| * The operation is _terminal_. |
| * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. |
| */ |
| public suspend inline fun <E> ReceiveChannel<E>.partition(predicate: (E) -> Boolean): Pair<List<E>, List<E>> { |
| val first = ArrayList<E>() |
| val second = ArrayList<E>() |
| consumeEach { |
| if (predicate(it)) { |
| first.add(it) |
| } else { |
| second.add(it) |
| } |
| } |
| return Pair(first, second) |
| } |
| |
| /** |
| * Returns a channel of pairs built from elements of both channels with same indexes. |
| * Resulting channel has length of shortest input channel. |
| * |
| * The operation is _intermediate_ and _stateless_. |
| * This function [consumes][ReceiveChannel.consume] all elements of both the original [ReceiveChannel] and the `other` one. |
| */ |
| public infix fun <E, R> ReceiveChannel<E>.zip(other: ReceiveChannel<R>): ReceiveChannel<Pair<E, R>> = |
| zip(other) { t1, t2 -> t1 to t2 } |
| |
| /** |
| * Returns a channel of values built from elements of both collections with same indexes using provided [transform]. Resulting channel has length of shortest input channels. |
| * |
| * The operation is _intermediate_ and _stateless_. |
| * This function [consumes][consume] all elements of both the original [ReceiveChannel] and the `other` one. |
| */ |
| // todo: mark transform with crossinline modifier when it is supported: https://youtrack.jetbrains.com/issue/KT-19159 |
| public fun <E, R, V> ReceiveChannel<E>.zip(other: ReceiveChannel<R>, context: CoroutineContext = Unconfined, transform: (a: E, b: R) -> V): ReceiveChannel<V> = |
| produce(context, onCompletion = consumesAll(this, other)) { |
| val otherIterator = other.iterator() |
| this@zip.consumeEach { element1 -> |
| if (!otherIterator.hasNext()) return@consumeEach |
| val element2 = otherIterator.next() |
| send(transform(element1, element2)) |
| } |
| } |
| |
| |