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/*
* Copyright (C) 2002-2023 Sebastiano Vigna
*
* 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.
*/
package it.unimi.dsi.fastutil.longs;
import java.util.Spliterator;
import java.util.function.Consumer;
/**
* A type-specific {@link Spliterator}; provides an additional methods to avoid (un)boxing, and the
* possibility to skip elements.
*
* @author C. Sean Young <[email protected]>
* @see Spliterator
* @since 8.5.0
*/
public interface LongSpliterator extends Spliterator.OfLong {
// tryAdvance(KEY_CONSUMER action) declaration inherited from super interface.
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
default boolean tryAdvance(final Consumer action) {
// The instanceof and cast is required for performance. Without it, calls routed through this
// overload using a primitive consumer would go through the slow lambda.
return tryAdvance(action instanceof java.util.function.LongConsumer ? (java.util.function.LongConsumer)action : (java.util.function.LongConsumer)action::accept);
}
// Because our primitive Consumer interface extends both the JDK's primitive
// and object Consumer interfaces, calling this method with it would be ambiguous.
// This overload exists to pass it to the proper primitive overload.
/**
* Attempts to perform the action on the next element, or do nothing but return {@code false} if
* there are no remaining elements.
*
*
* WARNING: Overriding this method is almost always a mistake, as this overload only exists
* to disambiguate. Instead, override the {@code tryAdvance()} overload that uses the JDK's
* primitive consumer type (e.g., {@link java.util.function.IntConsumer}).
*
*
* If Java supported final default methods, this would be one, but sadly it does not.
*
*
* If you checked and are overriding the version with {@code java.util.function.XConsumer}, and
* still see this warning, then your IDE is incorrectly conflating this method with the proper
* method to override, and you can safely ignore this message.
*
* @param action the action to be performed on the next element.
* @return whether there was a next element the action was performed on
* @see java.util.Spliterator#tryAdvance(java.util.function.Consumer)
*/
default boolean tryAdvance(final LongConsumer action) {
return tryAdvance((java.util.function.LongConsumer)action);
}
// forEachRemaining(KEY_CONSUMER action) default impl inherited from super interface.
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
default void forEachRemaining(final Consumer action) {
// The instanceof and cast is required for performance. Without it, calls routed through this
// overload using a primitive consumer would go through the slow lambda.
// This is not just theoretical; Oracle's Stream implementation (Pipeline) routes primitive
// consumer calls through this overload, and the difference in performance is an order
// of magnitude.
forEachRemaining(action instanceof java.util.function.LongConsumer ? (java.util.function.LongConsumer)action : (java.util.function.LongConsumer)action::accept);
}
// Because our primitive Consumer interface extends both the JDK's primitive
// and object Consumer interfaces, calling this method with it would be ambiguous.
// This overload exists to pass it to the proper primitive overload.
/**
* Performs the given action for each remaining element until all elements have been processed or
* the action throws an exception.
*
*
* WARNING: Overriding this method is almost always a mistake, as this overload only exists
* to disambiguate. Instead, override the {@code forEachRemaining()} overload that uses the JDK's
* primitive consumer type (e.g. {@link java.util.function.IntConsumer}).
*
*
* If Java supported final default methods, this would be one, but sadly it does not.
*
*
* If you checked and are overriding the version with {@code java.util.function.XConsumer}, and
* still see this warning, then your IDE is incorrectly conflating this method with the proper
* method to override, and you can safely ignore this message.
*
* @param action the action to be performed for each element.
* @see java.util.Spliterator#forEachRemaining(java.util.function.Consumer)
*/
default void forEachRemaining(final LongConsumer action) {
forEachRemaining((java.util.function.LongConsumer)action);
}
/**
* Skips the given number of elements.
*
*
* The effect of this call is exactly the same as that of calling {@link #tryAdvance} for {@code n}
* times (possibly stopping if {@link #tryAdvance} returns false). The action called will do
* nothing; elements will be discarded.
*
* @implSpec This default implementation is linear in n. It is expected concrete implementations
* that are capable of it will override it to run lower time, but be prepared for linear
* time.
*
* @param n the number of elements to skip.
* @return the number of elements actually skipped.
* @see Spliterator#tryAdvance
*/
default long skip(final long n) {
if (n < 0) throw new IllegalArgumentException("Argument must be nonnegative: " + n);
long i = n;
while (i-- != 0 && tryAdvance((long unused) -> {
})) {
} // No loop body; logic all happens in conditional
return n - i - 1;
}
/**
* {@inheritDoc}
*
* @apiNote Note that this specification strengthens the one given in
* {@link Spliterator#trySplit()}.
*/
@Override
LongSpliterator trySplit();
/**
* {@inheritDoc}
*
* @apiNote Note that this specification strengthens the one given in
* {@link Spliterator#getComparator()}.
*/
@Override
default LongComparator getComparator() {
throw new IllegalStateException();
}
}