--- a/jdk/src/share/classes/java/util/Arrays.java Wed Jun 26 06:32:40 2013 -0700
+++ b/jdk/src/share/classes/java/util/Arrays.java Wed Jun 26 15:30:39 2013 +0100
@@ -1559,6 +1559,183 @@
}
}
+ // Parallel prefix
+
+ /**
+ * Cumulates, in parallel, each element of the given array in place,
+ * using the supplied function. For example if the array initially
+ * holds {@code [2, 1, 0, 3]} and the operation performs addition,
+ * then upon return the array holds {@code [2, 3, 3, 6]}.
+ * Parallel prefix computation is usually more efficient than
+ * sequential loops for large arrays.
+ *
+ * @param array the array, which is modified in-place by this method
+ * @param op a side-effect-free, associative function to perform the
+ * cumulation
+ * @throws NullPointerException if the specified array or function is null
+ * @since 1.8
+ */
+ public static <T> void parallelPrefix(T[] array, BinaryOperator<T> op) {
+ if (array.length > 0)
+ new ArrayPrefixHelpers.CumulateTask<>
+ (null, op, array, 0, array.length).invoke();
+ }
+
+ /**
+ * Performs {@link #parallelPrefix(Object[], BinaryOperator)}
+ * for the given subrange of the array.
+ *
+ * @param array the array
+ * @param fromIndex the index of the first element, inclusive
+ * @param toIndex the index of the last element, exclusive
+ * @param op a side-effect-free, associative function to perform the
+ * cumulation
+ * @throws IllegalArgumentException if {@code fromIndex > toIndex}
+ * @throws ArrayIndexOutOfBoundsException
+ * if {@code fromIndex < 0} or {@code toIndex > array.length}
+ * @throws NullPointerException if the specified array or function is null
+ * @since 1.8
+ */
+ public static <T> void parallelPrefix(T[] array, int fromIndex,
+ int toIndex, BinaryOperator<T> op) {
+ rangeCheck(array.length, fromIndex, toIndex);
+ if (fromIndex < toIndex)
+ new ArrayPrefixHelpers.CumulateTask<>
+ (null, op, array, fromIndex, toIndex).invoke();
+ }
+
+ /**
+ * Cumulates, in parallel, each element of the given array in place,
+ * using the supplied function. For example if the array initially
+ * holds {@code [2, 1, 0, 3]} and the operation performs addition,
+ * then upon return the array holds {@code [2, 3, 3, 6]}.
+ * Parallel prefix computation is usually more efficient than
+ * sequential loops for large arrays.
+ *
+ * @param array the array, which is modified in-place by this method
+ * @param op a side-effect-free, associative function to perform the
+ * cumulation
+ * @throws NullPointerException if the specified array or function is null
+ * @since 1.8
+ */
+ public static void parallelPrefix(long[] array, LongBinaryOperator op) {
+ if (array.length > 0)
+ new ArrayPrefixHelpers.LongCumulateTask
+ (null, op, array, 0, array.length).invoke();
+ }
+
+ /**
+ * Performs {@link #parallelPrefix(long[], LongBinaryOperator)}
+ * for the given subrange of the array.
+ *
+ * @param array the array
+ * @param fromIndex the index of the first element, inclusive
+ * @param toIndex the index of the last element, exclusive
+ * @param op a side-effect-free, associative function to perform the
+ * cumulation
+ * @throws IllegalArgumentException if {@code fromIndex > toIndex}
+ * @throws ArrayIndexOutOfBoundsException
+ * if {@code fromIndex < 0} or {@code toIndex > array.length}
+ * @throws NullPointerException if the specified array or function is null
+ * @since 1.8
+ */
+ public static void parallelPrefix(long[] array, int fromIndex,
+ int toIndex, LongBinaryOperator op) {
+ rangeCheck(array.length, fromIndex, toIndex);
+ if (fromIndex < toIndex)
+ new ArrayPrefixHelpers.LongCumulateTask
+ (null, op, array, fromIndex, toIndex).invoke();
+ }
+
+ /**
+ * Cumulates, in parallel, each element of the given array in place,
+ * using the supplied function. For example if the array initially
+ * holds {@code [2.0, 1.0, 0.0, 3.0]} and the operation performs addition,
+ * then upon return the array holds {@code [2.0, 3.0, 3.0, 6.0]}.
+ * Parallel prefix computation is usually more efficient than
+ * sequential loops for large arrays.
+ *
+ * <p> Because floating-point operations may not be strictly associative,
+ * the returned result may not be identical to the value that would be
+ * obtained if the operation was performed sequentially.
+ *
+ * @param array the array, which is modified in-place by this method
+ * @param op a side-effect-free function to perform the cumulation
+ * @throws NullPointerException if the specified array or function is null
+ * @since 1.8
+ */
+ public static void parallelPrefix(double[] array, DoubleBinaryOperator op) {
+ if (array.length > 0)
+ new ArrayPrefixHelpers.DoubleCumulateTask
+ (null, op, array, 0, array.length).invoke();
+ }
+
+ /**
+ * Performs {@link #parallelPrefix(double[], DoubleBinaryOperator)}
+ * for the given subrange of the array.
+ *
+ * @param array the array
+ * @param fromIndex the index of the first element, inclusive
+ * @param toIndex the index of the last element, exclusive
+ * @param op a side-effect-free, associative function to perform the
+ * cumulation
+ * @throws IllegalArgumentException if {@code fromIndex > toIndex}
+ * @throws ArrayIndexOutOfBoundsException
+ * if {@code fromIndex < 0} or {@code toIndex > array.length}
+ * @throws NullPointerException if the specified array or function is null
+ * @since 1.8
+ */
+ public static void parallelPrefix(double[] array, int fromIndex,
+ int toIndex, DoubleBinaryOperator op) {
+ rangeCheck(array.length, fromIndex, toIndex);
+ if (fromIndex < toIndex)
+ new ArrayPrefixHelpers.DoubleCumulateTask
+ (null, op, array, fromIndex, toIndex).invoke();
+ }
+
+ /**
+ * Cumulates, in parallel, each element of the given array in place,
+ * using the supplied function. For example if the array initially
+ * holds {@code [2, 1, 0, 3]} and the operation performs addition,
+ * then upon return the array holds {@code [2, 3, 3, 6]}.
+ * Parallel prefix computation is usually more efficient than
+ * sequential loops for large arrays.
+ *
+ * @param array the array, which is modified in-place by this method
+ * @param op a side-effect-free, associative function to perform the
+ * cumulation
+ * @throws NullPointerException if the specified array or function is null
+ * @since 1.8
+ */
+ public static void parallelPrefix(int[] array, IntBinaryOperator op) {
+ if (array.length > 0)
+ new ArrayPrefixHelpers.IntCumulateTask
+ (null, op, array, 0, array.length).invoke();
+ }
+
+ /**
+ * Performs {@link #parallelPrefix(int[], IntBinaryOperator)}
+ * for the given subrange of the array.
+ *
+ * @param array the array
+ * @param fromIndex the index of the first element, inclusive
+ * @param toIndex the index of the last element, exclusive
+ * @param op a side-effect-free, associative function to perform the
+ * cumulation
+ * @throws IllegalArgumentException if {@code fromIndex > toIndex}
+ * @throws ArrayIndexOutOfBoundsException
+ * if {@code fromIndex < 0} or {@code toIndex > array.length}
+ * @throws NullPointerException if the specified array or function is null
+ * @since 1.8
+ */
+ public static void parallelPrefix(int[] array, int fromIndex,
+ int toIndex, IntBinaryOperator op) {
+ rangeCheck(array.length, fromIndex, toIndex);
+ if (fromIndex < toIndex)
+ new ArrayPrefixHelpers.IntCumulateTask
+ (null, op, array, fromIndex, toIndex).invoke();
+ }
+
// Searching
/**