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* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
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*
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
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*
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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 {@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.
*
* @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 {@code int} values.
* @since 1.8
*/
public static interface OfInt extends PrimitiveIterator<Integer, IntConsumer> {
/**
* 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.
*
* @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}
* @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}
* @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 {@code long} values.
* @since 1.8
*/
public static interface OfLong extends PrimitiveIterator<Long, LongConsumer> {
/**
* 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.
*
* @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}
* @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}
* @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 {@code double} values.
* @since 1.8
*/
public static interface OfDouble extends PrimitiveIterator<Double, DoubleConsumer> {
/**
* 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.
*
* @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}
* @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}
* @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);
}
}
}
}