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The module for FunctionalJ Core.
// ============================================================================
// Copyright (c) 2017-2021 Nawapunth Manusitthipol (NawaMan - http://nawaman.net).
// ----------------------------------------------------------------------------
// MIT License
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
// ============================================================================
package functionalj.stream;
import static functionalj.stream.StreamPlusHelper.sequentialToObj;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReference;
import java.util.function.BiFunction;
import java.util.function.Function;
import java.util.stream.Collectors;
import functionalj.function.Func1;
import functionalj.function.FuncUnit1;
import functionalj.promise.DeferAction;
import functionalj.promise.UncompletedAction;
import functionalj.result.Result;
import functionalj.stream.markers.Sequential;
import functionalj.tuple.Tuple2;
import lombok.val;
public interface StreamPlusWithModify {
public StreamPlus streamPlus();
/**
* Accumulate the previous to the next element.
*
* For example:
* inputs = [i1, i2, i3, i4, i5, i6, i7, i8, i9, i10]
* and ~ is a accumulate function
*
* From this we get
* acc0 = head of inputs => i1
* rest0 = tail of inputs => [i2, i3, i4, i5, i6, i7, i8, i9, i10]
*
* The outputs are:
* output0 = acc0 with acc1 = acc0 ~ rest0 and rest1 = rest of rest0
* output1 = acc1 with acc2 = acc1 ~ rest1 and rest2 = rest of rest1
* output2 = acc2 with acc3 = acc2 ~ rest2 and rest3 = rest of rest2
* ...
*/
@Sequential(knownIssue = true, comment = "Need to enforce the sequential.")
public default StreamPlus accumulate(BiFunction accumulator) {
val streamPlus = streamPlus();
val iterator = streamPlus.iterator();
if (!iterator.hasNext())
return StreamPlus.empty();
val prev = new AtomicReference(iterator.next());
return StreamPlus
.concat(
StreamPlus.of(prev.get()),
iterator
.stream()
.map(each -> {
val next = accumulator.apply(prev.get(), each);
prev.set(next);
return next;
})
);
}
/**
* Use each of the element to recreate the stream by applying each element to the rest of the stream and repeat.
*
* For example:
* inputs = [i1, i2, i3, i4, i5, i6, i7, i8, i9, i10]
* and ~ is a restate function
*
* From this we get
* head0 = head of inputs = i1
* rest0 = tail of inputs = [i2, i3, i4, i5, i6, i7, i8, i9, i10]
*
* The outputs are:
* output0 = head0 with rest1 = head0 ~ rest0 and head1 = head of rest0
* output1 = head1 with rest2 = head1 ~ rest1 and head2 = head of rest2
* output2 = head2 with rest3 = head2 ~ rest2 and head3 = head of rest3
* ...
**/
@Sequential(knownIssue = true, comment = "Need to enforce the sequential.")
@SuppressWarnings({ "unchecked" })
public default StreamPlus restate(BiFunction, StreamPlus> restater) {
Func1>, Tuple2>> func = ((Tuple2> pair) -> {
val stream = pair._2();
if (stream == null)
return null;
val head = new Object[] { null };
val iterator = stream.iterator();
if (!iterator.hasNext())
return null;
head[0] = iterator.next();
val tail = restater.apply((DATA)head[0], iterator.stream());
if (tail == null)
return null;
return Tuple2.of((DATA)head[0], tail);
});
val seed = Tuple2.of((DATA)null, this.streamPlus());
return StreamPlus
.iterate (seed, func)
.takeUntil(t -> t == null)
.skip (1)
.map (t -> t._1());
}
/**
* Map each element to a uncompleted action, run them and collect which ever finish first.
* The result stream will not be the same order with the original one
* -- as stated, the order will be the order of completion.
* If the result StreamPlus is closed (which is done every times a terminal operation is done),
* the unfinished actions will be canceled.
*/
public default StreamPlus> spawn(Function> mapToAction) {
val streamPlus = streamPlus();
return sequentialToObj(streamPlus, stream -> {
val results = new ArrayList>();
val index = new AtomicInteger(0);
FuncUnit1> setOnComplete = action ->
action
.getPromise()
.onComplete(result -> {
val thisIndex = index.getAndIncrement();
val thisAction = results.get(thisIndex);
if (result.isValue())
thisAction.complete(result.value());
else thisAction.fail (result.exception());
});
List> actions
= stream
.mapToObj(mapToAction)
.peek (action -> results.add(DeferAction.createNew()))
.peek (action -> setOnComplete.accept(action))
.peek (action -> action.start())
.collect (Collectors.toList())
;
val resultStream
= StreamPlus
.from(results.stream().map(action -> action.getResult()));
resultStream
.onClose(()->actions.forEach(action -> action.abort("Stream closed!")));
return resultStream;
});
}
// TODO - Add insertBetween -> do mapTwo and return an element to be inserted in.
// insertBetween(BiFunction)
// insertBetween(Function, DATA>)
// insertBetween(IntBiFunction, DATA>)
}