/** Sort the ratings. */
private void sortRatings() {
int[] invMap = new int[index];
for (int i = index - 1; i >= 0; i--) {
invMap[i] = i;
}
Arrays.quickSort(0, index, new SortComparator(), new SortSwapper(invMap));
translationMap = new int[index];
for (int i = 0; i < invMap.length; i++) {
translationMap[invMap[i]] = i;
}
}
/**
* Ensures that a range given by an offset and a length fits an array.
*
* <p>This method may be used whenever an array range check is needed.
*
* @param a an array.
* @param offset a start index.
* @param length a length (the number of elements in the range).
* @throws IllegalArgumentException if <code>length</code> is negative.
* @throws ArrayIndexOutOfBoundsException if <code>offset</code> is negative or <code>offset
* </code>+<code>length</code> is greater than the array length.
*/
public static void ensureOffsetLength(final long[] a, final int offset, final int length) {
Arrays.ensureOffsetLength(a.length, offset, length);
}
/**
* Ensures that a range given by its first (inclusive) and last (exclusive) elements fits an
* array.
*
* <p>This method may be used whenever an array range check is needed.
*
* @param a an array.
* @param from a start index (inclusive).
* @param to an end index (inclusive).
* @throws IllegalArgumentException if <code>from</code> is greater than <code>to</code>.
* @throws ArrayIndexOutOfBoundsException if <code>from</code> or <code>to</code> are greater than
* the array length or negative.
*/
public static void ensureFromTo(final long[] a, final int from, final int to) {
Arrays.ensureFromTo(a.length, from, to);
}