it.unimi.dsi.fastutil.doubles.DoubleSpliterator Maven / Gradle / Ivy
/*
* Copyright (C) 2002-2022 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.doubles;
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 DoubleSpliterator extends Spliterator.OfDouble {
// 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.DoubleConsumer ? (java.util.function.DoubleConsumer)action : (java.util.function.DoubleConsumer) 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 DoubleConsumer action) {
return tryAdvance((java.util.function.DoubleConsumer) 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.DoubleConsumer ? (java.util.function.DoubleConsumer)action : (java.util.function.DoubleConsumer) 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 DoubleConsumer action) {
forEachRemaining((java.util.function.DoubleConsumer) 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((double 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
DoubleSpliterator trySplit();
/**
* {@inheritDoc}
*
* @apiNote Note that this specification strengthens the one given in {@link Spliterator#getComparator()}.
*/
@Override
default DoubleComparator getComparator() {
throw new IllegalStateException();
}
}