java.util.function.IntUnaryOperator#applyAsInt ( )源码实例Demo

/**
 * Returns an infinite sequential ordered {@code IntStream} produced by iterative
 * application of a function {@code f} to an initial element {@code seed},
 * producing a {@code Stream} consisting of {@code seed}, {@code f(seed)},
 * {@code f(f(seed))}, etc.
 *
 * <p>The first element (position {@code 0}) in the {@code IntStream} will be
 * the provided {@code seed}.  For {@code n > 0}, the element at position
 * {@code n}, will be the result of applying the function {@code f} to the
 * element at position {@code n - 1}.
 *
 * @param seed the initial element
 * @param f a function to be applied to to the previous element to produce
 *          a new element
 * @return A new sequential {@code IntStream}
 */
public static IntStream iterate(final int seed, final IntUnaryOperator f) {
    Objects.requireNonNull(f);
    final PrimitiveIterator.OfInt iterator = new PrimitiveIterator.OfInt() {
        int t = seed;

        @Override
        public boolean hasNext() {
            return true;
        }

        @Override
        public int nextInt() {
            int v = t;
            t = f.applyAsInt(t);
            return v;
        }
    };
    return StreamSupport.intStream(Spliterators.spliteratorUnknownSize(
            iterator,
            Spliterator.ORDERED | Spliterator.IMMUTABLE | Spliterator.NONNULL), false);
}
 

/**
 * Returns an infinite sequential ordered {@code IntStream} produced by iterative
 * application of a function {@code f} to an initial element {@code seed},
 * producing a {@code Stream} consisting of {@code seed}, {@code f(seed)},
 * {@code f(f(seed))}, etc.
 *
 * <p>The first element (position {@code 0}) in the {@code IntStream} will be
 * the provided {@code seed}.  For {@code n > 0}, the element at position
 * {@code n}, will be the result of applying the function {@code f} to the
 * element at position {@code n - 1}.
 *
 * @param seed the initial element
 * @param f a function to be applied to to the previous element to produce
 *          a new element
 * @return A new sequential {@code IntStream}
 */
public static IntStream iterate(final int seed, final IntUnaryOperator f) {
    Objects.requireNonNull(f);
    final PrimitiveIterator.OfInt iterator = new PrimitiveIterator.OfInt() {
        int t = seed;

        @Override
        public boolean hasNext() {
            return true;
        }

        @Override
        public int nextInt() {
            int v = t;
            t = f.applyAsInt(t);
            return v;
        }
    };
    return StreamSupport.intStream(Spliterators.spliteratorUnknownSize(
            iterator,
            Spliterator.ORDERED | Spliterator.IMMUTABLE | Spliterator.NONNULL), false);
}
 

/**
 * Returns an infinite sequential ordered {@code IntStream} produced by iterative
 * application of a function {@code f} to an initial element {@code seed},
 * producing a {@code Stream} consisting of {@code seed}, {@code f(seed)},
 * {@code f(f(seed))}, etc.
 *
 * <p>The first element (position {@code 0}) in the {@code IntStream} will be
 * the provided {@code seed}.  For {@code n > 0}, the element at position
 * {@code n}, will be the result of applying the function {@code f} to the
 * element at position {@code n - 1}.
 *
 * @param seed the initial element
 * @param f a function to be applied to the previous element to produce
 *          a new element
 * @return A new sequential {@code IntStream}
 */
public static IntStream iterate(final int seed, final IntUnaryOperator f) {
    Objects.requireNonNull(f);
    final PrimitiveIterator.OfInt iterator = new PrimitiveIterator.OfInt() {
        int t = seed;

        @Override
        public boolean hasNext() {
            return true;
        }

        @Override
        public int nextInt() {
            int v = t;
            t = f.applyAsInt(t);
            return v;
        }
    };
    return StreamSupport.intStream(Spliterators.spliteratorUnknownSize(
            iterator,
            Spliterator.ORDERED | Spliterator.IMMUTABLE | Spliterator.NONNULL), false);
}
 

private static Block bucketBlock(Block block, int count, IntUnaryOperator hasher)
{
    BlockBuilder builder = INTEGER.createFixedSizeBlockBuilder(block.getPositionCount());
    for (int position = 0; position < block.getPositionCount(); position++) {
        if (block.isNull(position)) {
            builder.appendNull();
            continue;
        }
        int hash = hasher.applyAsInt(position);
        int bucket = (hash & Integer.MAX_VALUE) % count;
        INTEGER.writeLong(builder, bucket);
    }
    return builder.build();
}
 

public static int indexOf(IntUnaryOperator a, int key, int count, boolean rev, boolean equal) {
	int lo = 0;
	int hi = count - 1;
	while (lo <= hi) {
		// Key is in a[lo..hi] or not present.
		int mid = lo + (hi - lo) / 2;
		int value = a.applyAsInt(mid);
		int comp = Integer.compare(key, value);
		if (rev) {
			if (!equal && comp >= 0 || equal && comp > 0)
				hi = mid - 1;
			else if (!equal && comp < 0 || equal && comp <= 0)
				lo = mid + 1;
			else
				return mid;
		} else {
			if (!equal && comp <= 0 || equal && comp < 0)
				hi = mid - 1;
			else if (!equal && comp > 0 || equal && comp >= 0)
				lo = mid + 1;
			else
				return mid;
		}

	}
	return lo;
}
 

/**
 * Primitive specialised version of {@link #computeIfAbsent(Object, Function)}
 *
 * @param key             to search on.
 * @param mappingFunction to provide a value if the get returns null.
 * @return the value if found otherwise the missing value.
 */
public int computeIfAbsent(final int key, final IntUnaryOperator mappingFunction)
{
    int value = get(key);
    if (value == missingValue)
    {
        value = mappingFunction.applyAsInt(key);
        if (value != missingValue)
        {
            put(key, value);
        }
    }

    return value;
}
 

/**
 * Atomically updates the current value with the results of
 * applying the given function, returning the previous value. The
 * function should be side-effect-free, since it may be re-applied
 * when attempted updates fail due to contention among threads.
 *
 * @param updateFunction a side-effect-free function
 * @return the previous value
 * @since 1.8
 */
public final int getAndUpdate(IntUnaryOperator updateFunction) {
    int prev, next;
    do {
        prev = get();
        next = updateFunction.applyAsInt(prev);
    } while (!compareAndSet(prev, next));
    return prev;
}
 

/**
 * Atomically updates the element at index {@code i} with the results
 * of applying the given function, returning the previous value. The
 * function should be side-effect-free, since it may be re-applied
 * when attempted updates fail due to contention among threads.
 *
 * @param i the index
 * @param updateFunction a side-effect-free function
 * @return the previous value
 * @since 1.8
 */
public final int getAndUpdate(int i, IntUnaryOperator updateFunction) {
    long offset = checkedByteOffset(i);
    int prev, next;
    do {
        prev = getRaw(offset);
        next = updateFunction.applyAsInt(prev);
    } while (!compareAndSetRaw(offset, prev, next));
    return prev;
}
 

/**
 * Atomically updates the current value with the results of
 * applying the given function, returning the previous value. The
 * function should be side-effect-free, since it may be re-applied
 * when attempted updates fail due to contention among threads.
 *
 * @param updateFunction a side-effect-free function
 * @return the previous value
 * @since 1.8
 */
public final int getAndUpdate(IntUnaryOperator updateFunction) {
    int prev, next;
    do {
        prev = get();
        next = updateFunction.applyAsInt(prev);
    } while (!compareAndSet(prev, next));
    return prev;
}
 

/**
 * Atomically updates the current value with the results of
 * applying the given function, returning the previous value. The
 * function should be side-effect-free, since it may be re-applied
 * when attempted updates fail due to contention among threads.
 *
 * @param updateFunction a side-effect-free function
 * @return the previous value
 * @since 1.8
 */
public final int getAndUpdate(IntUnaryOperator updateFunction) {
    int prev, next;
    do {
        prev = get();
        next = updateFunction.applyAsInt(prev);
    } while (!compareAndSet(prev, next));
    return prev;
}
 

/**
 * Atomically updates the field of the given object managed by this updater
 * with the results of applying the given function, returning the previous
 * value. The function should be side-effect-free, since it may be
 * re-applied when attempted updates fail due to contention among threads.
 *
 * @param obj An object whose field to get and set
 * @param updateFunction a side-effect-free function
 * @return the previous value
 * @since 1.8
 */
public final int getAndUpdate(T obj, IntUnaryOperator updateFunction) {
    int prev, next;
    do {
        prev = get(obj);
        next = updateFunction.applyAsInt(prev);
    } while (!compareAndSet(obj, prev, next));
    return prev;
}
 

/**
 * Atomically updates the field of the given object managed by this updater
 * with the results of applying the given function, returning the previous
 * value. The function should be side-effect-free, since it may be
 * re-applied when attempted updates fail due to contention among threads.
 *
 * @param obj An object whose field to get and set
 * @param updateFunction a side-effect-free function
 * @return the previous value
 * @since 1.8
 */
public final int getAndUpdate(T obj, IntUnaryOperator updateFunction) {
    int prev, next;
    do {
        prev = get(obj);
        next = updateFunction.applyAsInt(prev);
    } while (!compareAndSet(obj, prev, next));
    return prev;
}
 

/**
 * Atomically updates (with memory effects as specified by {@link
 * VarHandle#compareAndSet}) the element at index {@code i} with
 * the results of applying the given function, returning the
 * previous value. The function should be side-effect-free, since
 * it may be re-applied when attempted updates fail due to
 * contention among threads.
 *
 * @param i the index
 * @param updateFunction a side-effect-free function
 * @return the previous value
 * @since 1.8
 */
public final int getAndUpdate(int i, IntUnaryOperator updateFunction) {
    int prev = get(i), next = 0;
    for (boolean haveNext = false;;) {
        if (!haveNext)
            next = updateFunction.applyAsInt(prev);
        if (weakCompareAndSetVolatile(i, prev, next))
            return prev;
        haveNext = (prev == (prev = get(i)));
    }
}
 

/**
 * Atomically updates (with memory effects as specified by {@link
 * VarHandle#compareAndSet}) the field of the given object managed
 * by this updater with the results of applying the given
 * function, returning the updated value. The function should be
 * side-effect-free, since it may be re-applied when attempted
 * updates fail due to contention among threads.
 *
 * @param obj An object whose field to get and set
 * @param updateFunction a side-effect-free function
 * @return the updated value
 * @since 1.8
 */
public final int updateAndGet(T obj, IntUnaryOperator updateFunction) {
    int prev, next;
    do {
        prev = get(obj);
        next = updateFunction.applyAsInt(prev);
    } while (!compareAndSet(obj, prev, next));
    return next;
}
 

/**
 * Atomically updates the current value with the results of
 * applying the given function, returning the previous value. The
 * function should be side-effect-free, since it may be re-applied
 * when attempted updates fail due to contention among threads.
 *
 * @param updateFunction a side-effect-free function
 * @return the previous value
 * @since 1.8
 */
public final int getAndUpdate(IntUnaryOperator updateFunction) {
    int prev, next;
    do {
        prev = get();
        next = updateFunction.applyAsInt(prev);
    } while (!compareAndSet(prev, next));
    return prev;
}
 

/**
 * Atomically updates the element at index {@code i} with the results
 * of applying the given function, returning the updated value. The
 * function should be side-effect-free, since it may be re-applied
 * when attempted updates fail due to contention among threads.
 *
 * @param i the index
 * @param updateFunction a side-effect-free function
 * @return the updated value
 * @since 1.8
 */
public final int updateAndGet(int i, IntUnaryOperator updateFunction) {
    long offset = checkedByteOffset(i);
    int prev, next;
    do {
        prev = getRaw(offset);
        next = updateFunction.applyAsInt(prev);
    } while (!compareAndSetRaw(offset, prev, next));
    return next;
}
 

/**
 * Atomically updates the current value with the results of
 * applying the given function, returning the updated value. The
 * function should be side-effect-free, since it may be re-applied
 * when attempted updates fail due to contention among threads.
 *
 * @param updateFunction a side-effect-free function
 * @return the updated value
 * @since 1.8
 */
public final int updateAndGet(IntUnaryOperator updateFunction) {
    int prev, next;
    do {
        prev = get();
        next = updateFunction.applyAsInt(prev);
    } while (!compareAndSet(prev, next));
    return next;
}
 

/**
 * Atomically updates the element at index {@code i} with the results
 * of applying the given function, returning the updated value. The
 * function should be side-effect-free, since it may be re-applied
 * when attempted updates fail due to contention among threads.
 *
 * @param i the index
 * @param updateFunction a side-effect-free function
 * @return the updated value
 * @since 1.8
 */
public final int updateAndGet(int i, IntUnaryOperator updateFunction) {
    long offset = checkedByteOffset(i);
    int prev, next;
    do {
        prev = getRaw(offset);
        next = updateFunction.applyAsInt(prev);
    } while (!compareAndSetRaw(offset, prev, next));
    return next;
}
 

/**
 * Atomically updates the element at index {@code i} with the results
 * of applying the given function, returning the previous value. The
 * function should be side-effect-free, since it may be re-applied
 * when attempted updates fail due to contention among threads.
 *
 * @param i the index
 * @param updateFunction a side-effect-free function
 * @return the previous value
 * @since 1.8
 */
public final int getAndUpdate(int i, IntUnaryOperator updateFunction) {
    long offset = checkedByteOffset(i);
    int prev, next;
    do {
        prev = getRaw(offset);
        next = updateFunction.applyAsInt(prev);
    } while (!compareAndSetRaw(offset, prev, next));
    return prev;
}
 

/**
 * Atomically updates the current value with the results of
 * applying the given function, returning the previous value. The
 * function should be side-effect-free, since it may be re-applied
 * when attempted updates fail due to contention among threads.
 *
 * @param updateFunction a side-effect-free function
 * @return the previous value
 * @since 1.8
 */
public final int getAndUpdate(IntUnaryOperator updateFunction) {
    int prev, next;
    do {
        prev = get();
        next = updateFunction.applyAsInt(prev);
    } while (!compareAndSet(prev, next));
    return prev;
}