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package java.util;

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


A base type for primitive specializations of Iterator. Specialized subtypes are provided for int, long, and double values. 
The specialized subtype default implementations of Iterator.next and Iterator.forEachRemaining(Consumer) box primitive values to instances of their corresponding wrapper class. Such boxing may offset any advantages gained when using the primitive specializations. To avoid boxing, the corresponding primitive-based methods should be used. For example, OfInt.nextInt() and OfInt.forEachRemaining(IntConsumer) should be used in preference to OfInt.next() and OfInt.forEachRemaining(Consumer<? super Integer>). 
Iteration of primitive values using boxing-based methods next() and forEachRemaining(), does not affect the order in which the values, transformed to boxed values, are encountered. 
Type parameters:
  • <T> – the type of elements returned by this PrimitiveIterator. The type must be a wrapper type for a primitive type, such as Integer for the primitive int type.
  • <T_CONS> – the type of primitive consumer. The type must be a primitive specialization of Consumer for T, such as IntConsumer for Integer.
Implementation Note: If the boolean system property org.openjdk.java.util.stream.tripwire is set to true then diagnostic warnings are reported if boxing of primitive values occur when operating on primitive subtype specializations.
Since:1.8
/**
 * A base type for primitive specializations of {@code Iterator}.  Specialized
 * subtypes are provided for {@link OfInt int}, {@link OfLong long}, and
 * {@link OfDouble double} values.
 *
 * <p>The specialized subtype default implementations of {@link Iterator#next}
 * and {@link Iterator#forEachRemaining(java.util.function.Consumer)} box
 * primitive values to instances of their corresponding wrapper class.  Such
 * boxing may offset any advantages gained when using the primitive
 * specializations.  To avoid boxing, the corresponding primitive-based methods
 * should be used.  For example, {@link PrimitiveIterator.OfInt#nextInt()} and
 * {@link PrimitiveIterator.OfInt#forEachRemaining(java.util.function.IntConsumer)}
 * should be used in preference to {@link PrimitiveIterator.OfInt#next()} and
 * {@link PrimitiveIterator.OfInt#forEachRemaining(java.util.function.Consumer)}.
 *
 * <p>Iteration of primitive values using boxing-based methods
 * {@link Iterator#next next()} and
 * {@link Iterator#forEachRemaining(java.util.function.Consumer) forEachRemaining()},
 * does not affect the order in which the values, transformed to boxed values,
 * are encountered.
 *
 * @implNote
 * If the boolean system property {@code org.openjdk.java.util.stream.tripwire}
 * is set to {@code true} then diagnostic warnings are reported if boxing of
 * primitive values occur when operating on primitive subtype specializations.
 *
 * @param <T> the type of elements returned by this PrimitiveIterator.  The
 *        type must be a wrapper type for a primitive type, such as
 *        {@code Integer} for the primitive {@code int} type.
 * @param <T_CONS> the type of primitive consumer.  The type must be a
 *        primitive specialization of {@link java.util.function.Consumer} for
 *        {@code T}, such as {@link java.util.function.IntConsumer} for
 *        {@code Integer}.
 *
 * @since 1.8
 */
public interface PrimitiveIterator<T, T_CONS> extends Iterator<T> {

    
Performs the given action for each remaining element, in the order
elements occur when iterating, until all elements have been processed
or the action throws an exception.  Errors or runtime exceptions
thrown by the action are relayed to the caller.

Params:
  • action – The action to be performed for each element
Throws:
/**
     * Performs the given action for each remaining element, in the order
     * elements occur when iterating, until all elements have been processed
     * or the action throws an exception.  Errors or runtime exceptions
     * thrown by the action are relayed to the caller.
     *
     * @param action The action to be performed for each element
     * @throws NullPointerException if the specified action is null
     */
    @SuppressWarnings("overloads")
    void forEachRemaining(T_CONS action);

    
An Iterator specialized for int values. 
Since:1.8
/**
     * An Iterator specialized for {@code int} values.
     * @since 1.8
     */
    public static interface OfInt extends PrimitiveIterator<Integer, IntConsumer> {

        
Returns the next int element in the iteration. 
Throws:
Returns:the next int element in the iteration
/**
         * Returns the next {@code int} element in the iteration.
         *
         * @return the next {@code int} element in the iteration
         * @throws NoSuchElementException if the iteration has no more elements
         */
        int nextInt();

        
Performs the given action for each remaining element until all elements
have been processed or the action throws an exception.  Actions are
performed in the order of iteration, if that order is specified.
Exceptions thrown by the action are relayed to the caller.

Params:
  • action – The action to be performed for each element
Throws:
Implementation Requirements:

The default implementation behaves as if:


    while (hasNext())
        action.accept(nextInt());

/**
         * Performs the given action for each remaining element until all elements
         * have been processed or the action throws an exception.  Actions are
         * performed in the order of iteration, if that order is specified.
         * Exceptions thrown by the action are relayed to the caller.
         *
         * @implSpec
         * <p>The default implementation behaves as if:
         * <pre>{@code
         *     while (hasNext())
         *         action.accept(nextInt());
         * }</pre>
         *
         * @param action The action to be performed for each element
         * @throws NullPointerException if the specified action is null
         */
        default void forEachRemaining(IntConsumer action) {
            Objects.requireNonNull(action);
            while (hasNext())
                action.accept(nextInt());
        }

        
{@inheritDoc}

Implementation Requirements: The default implementation boxes the result of calling nextInt(), and returns that boxed result.
/**
         * {@inheritDoc}
         * @implSpec
         * The default implementation boxes the result of calling
         * {@link #nextInt()}, and returns that boxed result.
         */
        @Override
        default Integer next() {
            if (Tripwire.ENABLED)
                Tripwire.trip(getClass(), "{0} calling PrimitiveIterator.OfInt.nextInt()");
            return nextInt();
        }

        
{@inheritDoc}

Implementation Requirements: If the action is an instance of IntConsumer then it is cast to IntConsumer and passed to forEachRemaining; otherwise the action is adapted to an instance of IntConsumer, by boxing the argument of IntConsumer, and then passed to forEachRemaining.
/**
         * {@inheritDoc}
         * @implSpec
         * If the action is an instance of {@code IntConsumer} then it is cast
         * to {@code IntConsumer} and passed to {@link #forEachRemaining};
         * otherwise the action is adapted to an instance of
         * {@code IntConsumer}, by boxing the argument of {@code IntConsumer},
         * and then passed to {@link #forEachRemaining}.
         */
        @Override
        default void forEachRemaining(Consumer<? super Integer> action) {
            if (action instanceof IntConsumer) {
                forEachRemaining((IntConsumer) action);
            }
            else {
                // The method reference action::accept is never null
                Objects.requireNonNull(action);
                if (Tripwire.ENABLED)
                    Tripwire.trip(getClass(), "{0} calling PrimitiveIterator.OfInt.forEachRemainingInt(action::accept)");
                forEachRemaining((IntConsumer) action::accept);
            }
        }

    }

    
An Iterator specialized for long values. 
Since:1.8
/**
     * An Iterator specialized for {@code long} values.
     * @since 1.8
     */
    public static interface OfLong extends PrimitiveIterator<Long, LongConsumer> {

        
Returns the next long element in the iteration. 
Throws:
Returns:the next long element in the iteration
/**
         * Returns the next {@code long} element in the iteration.
         *
         * @return the next {@code long} element in the iteration
         * @throws NoSuchElementException if the iteration has no more elements
         */
        long nextLong();

        
Performs the given action for each remaining element until all elements
have been processed or the action throws an exception.  Actions are
performed in the order of iteration, if that order is specified.
Exceptions thrown by the action are relayed to the caller.

Params:
  • action – The action to be performed for each element
Throws:
Implementation Requirements:

The default implementation behaves as if:


    while (hasNext())
        action.accept(nextLong());

/**
         * Performs the given action for each remaining element until all elements
         * have been processed or the action throws an exception.  Actions are
         * performed in the order of iteration, if that order is specified.
         * Exceptions thrown by the action are relayed to the caller.
         *
         * @implSpec
         * <p>The default implementation behaves as if:
         * <pre>{@code
         *     while (hasNext())
         *         action.accept(nextLong());
         * }</pre>
         *
         * @param action The action to be performed for each element
         * @throws NullPointerException if the specified action is null
         */
        default void forEachRemaining(LongConsumer action) {
            Objects.requireNonNull(action);
            while (hasNext())
                action.accept(nextLong());
        }

        
{@inheritDoc}

Implementation Requirements: The default implementation boxes the result of calling nextLong(), and returns that boxed result.
/**
         * {@inheritDoc}
         * @implSpec
         * The default implementation boxes the result of calling
         * {@link #nextLong()}, and returns that boxed result.
         */
        @Override
        default Long next() {
            if (Tripwire.ENABLED)
                Tripwire.trip(getClass(), "{0} calling PrimitiveIterator.OfLong.nextLong()");
            return nextLong();
        }

        
{@inheritDoc}

Implementation Requirements: If the action is an instance of LongConsumer then it is cast to LongConsumer and passed to forEachRemaining; otherwise the action is adapted to an instance of LongConsumer, by boxing the argument of LongConsumer, and then passed to forEachRemaining.
/**
         * {@inheritDoc}
         * @implSpec
         * If the action is an instance of {@code LongConsumer} then it is cast
         * to {@code LongConsumer} and passed to {@link #forEachRemaining};
         * otherwise the action is adapted to an instance of
         * {@code LongConsumer}, by boxing the argument of {@code LongConsumer},
         * and then passed to {@link #forEachRemaining}.
         */
        @Override
        default void forEachRemaining(Consumer<? super Long> action) {
            if (action instanceof LongConsumer) {
                forEachRemaining((LongConsumer) action);
            }
            else {
                // The method reference action::accept is never null
                Objects.requireNonNull(action);
                if (Tripwire.ENABLED)
                    Tripwire.trip(getClass(), "{0} calling PrimitiveIterator.OfLong.forEachRemainingLong(action::accept)");
                forEachRemaining((LongConsumer) action::accept);
            }
        }
    }

    
An Iterator specialized for double values. 
Since:1.8
/**
     * An Iterator specialized for {@code double} values.
     * @since 1.8
     */
    public static interface OfDouble extends PrimitiveIterator<Double, DoubleConsumer> {

        
Returns the next double element in the iteration. 
Throws:
Returns:the next double element in the iteration
/**
         * Returns the next {@code double} element in the iteration.
         *
         * @return the next {@code double} element in the iteration
         * @throws NoSuchElementException if the iteration has no more elements
         */
        double nextDouble();

        
Performs the given action for each remaining element until all elements
have been processed or the action throws an exception.  Actions are
performed in the order of iteration, if that order is specified.
Exceptions thrown by the action are relayed to the caller.

Params:
  • action – The action to be performed for each element
Throws:
Implementation Requirements:

The default implementation behaves as if:


    while (hasNext())
        action.accept(nextDouble());

/**
         * Performs the given action for each remaining element until all elements
         * have been processed or the action throws an exception.  Actions are
         * performed in the order of iteration, if that order is specified.
         * Exceptions thrown by the action are relayed to the caller.
         *
         * @implSpec
         * <p>The default implementation behaves as if:
         * <pre>{@code
         *     while (hasNext())
         *         action.accept(nextDouble());
         * }</pre>
         *
         * @param action The action to be performed for each element
         * @throws NullPointerException if the specified action is null
         */
        default void forEachRemaining(DoubleConsumer action) {
            Objects.requireNonNull(action);
            while (hasNext())
                action.accept(nextDouble());
        }

        
{@inheritDoc}

Implementation Requirements: The default implementation boxes the result of calling nextDouble(), and returns that boxed result.
/**
         * {@inheritDoc}
         * @implSpec
         * The default implementation boxes the result of calling
         * {@link #nextDouble()}, and returns that boxed result.
         */
        @Override
        default Double next() {
            if (Tripwire.ENABLED)
                Tripwire.trip(getClass(), "{0} calling PrimitiveIterator.OfDouble.nextLong()");
            return nextDouble();
        }

        
{@inheritDoc}

Implementation Requirements: If the action is an instance of DoubleConsumer then it is cast to DoubleConsumer and passed to forEachRemaining; otherwise the action is adapted to an instance of DoubleConsumer, by boxing the argument of DoubleConsumer, and then passed to forEachRemaining.
/**
         * {@inheritDoc}
         * @implSpec
         * If the action is an instance of {@code DoubleConsumer} then it is
         * cast to {@code DoubleConsumer} and passed to
         * {@link #forEachRemaining}; otherwise the action is adapted to
         * an instance of {@code DoubleConsumer}, by boxing the argument of
         * {@code DoubleConsumer}, and then passed to
         * {@link #forEachRemaining}.
         */
        @Override
        default void forEachRemaining(Consumer<? super Double> action) {
            if (action instanceof DoubleConsumer) {
                forEachRemaining((DoubleConsumer) action);
            }
            else {
                // The method reference action::accept is never null
                Objects.requireNonNull(action);
                if (Tripwire.ENABLED)
                    Tripwire.trip(getClass(), "{0} calling PrimitiveIterator.OfDouble.forEachRemainingDouble(action::accept)");
                forEachRemaining((DoubleConsumer) action::accept);
            }
        }
    }
}