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Primitives: Expanding upon java.util.PrimitiveIterator and java.util.function.* for {byte, char, float, short}
package io.deephaven.engine.primitive.iterator;
import io.deephaven.engine.primitive.function.CharConsumer;
import io.deephaven.engine.primitive.function.CharToIntFunction;
import io.deephaven.util.SafeCloseableArray;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import java.util.NoSuchElementException;
import java.util.Objects;
import java.util.function.Consumer;
import java.util.stream.IntStream;
/**
* {@link CloseablePrimitiveIterator Closeable primitive iterator} over elements of type {@code char}.
*/
public interface CloseablePrimitiveIteratorOfChar extends CloseablePrimitiveIterator {
/**
* Returns the next {@code char} element in the iteration.
*
* @return The next {@code char} element in the iteration
* @throws NoSuchElementException if the iteration has no more elements
*/
char nextChar();
@Override
default void forEachRemaining(@NotNull final CharConsumer action) {
Objects.requireNonNull(action);
while (hasNext()) {
action.accept(nextChar());
}
}
@Override
default Character next() {
return nextChar();
}
@Override
default void forEachRemaining(@NotNull final Consumer action) {
if (action instanceof CharConsumer) {
forEachRemaining((CharConsumer) action);
} else {
Objects.requireNonNull(action);
forEachRemaining((CharConsumer) action::accept);
}
}
/**
* Adapt this CloseablePrimitiveIteratorOfChar to a {@link CloseablePrimitiveIteratorOfInt}, applying
* {@code adapter} to each element. Closing the result will close this CloseablePrimitiveIteratorOfChar.
*
* @param adapter The adapter to apply
* @return The adapted primitive iterator
*/
default CloseablePrimitiveIteratorOfInt adaptToOfInt(@NotNull final CharToIntFunction adapter) {
return new CloseablePrimitiveIteratorOfInt() {
@Override
public boolean hasNext() {
return CloseablePrimitiveIteratorOfChar.this.hasNext();
}
@Override
public int nextInt() {
return adapter.applyAsInt(CloseablePrimitiveIteratorOfChar.this.next());
}
@Override
public void close() {
CloseablePrimitiveIteratorOfChar.this.close();
}
};
}
/**
* Create a {@link IntStream} over the remaining elements of this CloseablePrimitiveIteratorOfChar by applying
* {@code adapter} to each element. Closing the result will close this CloseablePrimitiveIteratorOfChar.
*
* @return A {@link IntStream} over the remaining contents of this iterator
*/
default IntStream streamAsInt(@NotNull final CharToIntFunction adapter) {
// noinspection resource
return adaptToOfInt(adapter).intStream();
}
/**
* Create a {@link IntStream} over the remaining elements of this CloseablePrimitiveIteratorOfChar by applying an
* implementation-defined default adapter to each element. The default implementation applies a simple {@code int}
* cast. Closing the result will close this CloseablePrimitiveIteratorOfChar.
*
* @return A {@link IntStream} over the remaining contents of this iterator
*/
default IntStream streamAsInt() {
return streamAsInt(value -> (int) value);
}
/**
* A re-usable, immutable CloseablePrimitiveIteratorOfChar with no elements.
*/
CloseablePrimitiveIteratorOfChar EMPTY = new CloseablePrimitiveIteratorOfChar() {
@Override
public char nextChar() {
throw new NoSuchElementException();
}
@Override
public boolean hasNext() {
return false;
}
};
/**
* Get a CloseablePrimitiveIteratorOfChar with no elements. The result does not need to be {@link #close() closed}.
*
* @return A CloseablePrimitiveIteratorOfChar with no elements
*/
static CloseablePrimitiveIteratorOfChar empty() {
return EMPTY;
}
/**
* Create a CloseablePrimitiveIteratorOfChar over an array of {@code char}. The result does not need to be
* {@link #close() closed}.
*
* @param values The elements to iterate
* @return A CloseablePrimitiveIteratorOfChar of {@code values}
*/
static CloseablePrimitiveIteratorOfChar of(@NotNull final char... values) {
Objects.requireNonNull(values);
return new CloseablePrimitiveIteratorOfChar() {
private int valueIndex;
@Override
public char nextChar() {
if (valueIndex < values.length) {
return values[valueIndex++];
}
throw new NoSuchElementException();
}
@Override
public boolean hasNext() {
return valueIndex < values.length;
}
};
}
/**
* Create a CloseablePrimitiveIteratorOfChar that repeats {@code value}, {@code repeatCount} times. The result does
* not need to be {@link #close() closed}.
*
* @param value The value to repeat
* @param repeatCount The number of repetitions
* @return A CloseablePrimitiveIteratorOfChar that repeats {@code value}, {@code repeatCount} times
*/
static CloseablePrimitiveIteratorOfChar repeat(final char value, final long repeatCount) {
return new CloseablePrimitiveIteratorOfChar() {
private long repeatIndex;
@Override
public char nextChar() {
if (repeatIndex < repeatCount) {
++repeatIndex;
return value;
}
throw new NoSuchElementException();
}
@Override
public boolean hasNext() {
return repeatIndex < repeatCount;
}
};
}
/**
* Create a CloseablePrimitiveIteratorOfChar that concatenates an array of non-{@code null} {@code subIterators}.
* The result only needs to be {@link #close() closed} if any of the {@code subIterators} require it.
*
* @param subIterators The iterators to concatenate, none of which should be {@code null}. If directly passing an
* array, ensure that this iterator has full ownership.
* @return A CloseablePrimitiveIteratorOfChar concatenating all elements from {@code subIterators}
*/
static CloseablePrimitiveIteratorOfChar concat(@NotNull final CloseablePrimitiveIteratorOfChar... subIterators) {
Objects.requireNonNull(subIterators);
if (subIterators.length == 0) {
return empty();
}
if (subIterators.length == 1) {
return subIterators[0];
}
return new CloseablePrimitiveIteratorOfChar() {
private boolean hasNextChecked;
private int subIteratorIndex;
@Override
public char nextChar() {
if (hasNext()) {
hasNextChecked = false;
return subIterators[subIteratorIndex].nextChar();
}
throw new NoSuchElementException();
}
@Override
public boolean hasNext() {
if (hasNextChecked) {
return true;
}
for (; subIteratorIndex < subIterators.length; ++subIteratorIndex) {
if (subIterators[subIteratorIndex].hasNext()) {
return hasNextChecked = true;
}
}
return false;
}
@Override
public void close() {
SafeCloseableArray.close(subIterators);
}
};
}
/**
* Return a CloseablePrimitiveIteratorOfChar that concatenates the contents of any non-{@code null}
* CloseablePrimitiveIteratorOfChar found amongst {@code first}, {@code second}, and {@code third}.
*
* @param first The first iterator to consider concatenating
* @param second The second iterator to consider concatenating
* @param third The third iterator to consider concatenating
* @return A CloseablePrimitiveIteratorOfChar that concatenates all elements as specified
*/
static CloseablePrimitiveIteratorOfChar maybeConcat(
@Nullable final CloseablePrimitiveIteratorOfChar first,
@Nullable final CloseablePrimitiveIteratorOfChar second,
@Nullable final CloseablePrimitiveIteratorOfChar third) {
if (first != null) {
if (second != null) {
if (third != null) {
return concat(first, second, third);
}
return concat(first, second);
}
if (third != null) {
return concat(first, third);
}
return first;
}
if (second != null) {
if (third != null) {
return concat(second, third);
}
return second;
}
if (third != null) {
return third;
}
return empty();
}
}