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JHotDraw8 Utility classes for Collections
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/*
 * @(#)Spliterator.java
 * Copyright © 2023 The authors and contributors of JHotDraw. MIT License.
 */
package org.jhotdraw8.collection.enumerator;


import java.util.Iterator;
import java.util.Spliterator;
import java.util.function.Consumer;
import java.util.function.DoubleConsumer;
import java.util.function.IntConsumer;
import java.util.function.LongConsumer;

/**
 * Interface for classes that implement both the {@link BareEnumerator} and
 * the {@link Spliterator} interface.
 *
 * @param  the element type
 * @author Werner Randelshofer
 */
public interface Enumerator extends BareEnumerator, Spliterator {
    @Override
    default boolean tryAdvance(Consumer action) {
        if (moveNext()) {
            action.accept(current());
            return true;
        }
        return false;
    }

    /**
     * An object for enumerating primitive long-valued elements of a collection.
     * 
     * The protocol for accessing elements via a {@code Enumerator} imposes smaller per-element overhead than
     * {@link Iterator}, and avoids the inherent race involved in having separate methods for
     * {@code hasNext()} and {@code next()}.
     *
     * @author Werner Randelshofer
     */
    interface OfLong extends Enumerator, Spliterator.OfLong {

        /**
         * {@inheritDoc}
         */
        @Override
        default Long current() {
            return currentAsLong();
        }

        /**
         * Returns the current value.
         *
         * @return current
         * @see Enumerator#current()
         */
        long currentAsLong();

        /**
         * {@inheritDoc}
         */
        @Override
        default boolean tryAdvance(LongConsumer action) {
            if (moveNext()) {
                action.accept(currentAsLong());
                return true;
            }
            return false;
        }

        /**
         * {@inheritDoc}
         */
        @Override
        default boolean tryAdvance(Consumer action) {
            return Enumerator.super.tryAdvance(action);
        }

    }

    /**
     * An object for enumerating primitive double-valued elements of a collection.
     */
    interface OfDouble extends Enumerator, Spliterator.OfDouble {

        /**
         * {@inheritDoc}
         */
        @Override
        default Double current() {
            return currentAsDouble();
        }

        /**
         * Returns the current value.
         *
         * @return current
         * @see Enumerator#current()
         */
        double currentAsDouble();

        /**
         * {@inheritDoc}
         */
        @Override
        default boolean tryAdvance(DoubleConsumer action) {
            if (moveNext()) {
                action.accept(currentAsDouble());
                return true;
            }
            return false;
        }

        /**
         * {@inheritDoc}
         */
        @Override
        default boolean tryAdvance(Consumer action) {
            return Enumerator.super.tryAdvance(action);
        }

    }

    /**
     * An object for enumerating primitive int-valued elements of a collection.
     */
    interface OfInt extends Enumerator, Spliterator.OfInt {

        /**
         * {@inheritDoc}
         */
        @Override
        default Integer current() {
            return currentAsInt();
        }

        /**
         * Returns the current value.
         *
         * @return current
         * @see Enumerator#current()
         */
        int currentAsInt();

        /**
         * {@inheritDoc}
         */
        @Override
        default boolean tryAdvance(IntConsumer action) {
            if (moveNext()) {
                action.accept(currentAsInt());
                return true;
            }
            return false;
        }

        /**
         * {@inheritDoc}
         */
        @Override
        default boolean tryAdvance(Consumer action) {
            return Enumerator.super.tryAdvance(action);
        }

    }
}