Mainly for use with ArrayList to keep it sorted at insertion time. This method runs in `log(n)` time for a "random access" list (which provides near-constant-time positional access). If the specified list does not implement the `RandomAccess` interface and is large, this method will do an iterator-based binary search that performs `O(n)` link tr…

ListUtils.sortedAdd.java

private static final int NOT_UNIQUE = -1;

/**
 * Adds an item in a list using it's comparable sort
 *
 * @param item the item to add
 * @param list the list to add to
 * @param uniq if true, reject duplicates
 * @param <A> if
 * @param <I>
 * @param <L>
 * @return
 */
public static <A extends I, I extends Comparable<I>, L extends List<I>> int sortedAdd( A item, L list, boolean uniq ) {

    int size = list.size();
    int location = Collections.binarySearch( list, item );

    if ( location > 0 ) {
        if ( uniq )
            return NOT_UNIQUE;

        for ( ; location < size; location++ )
            if ( list.get( location ) != item )
                break;
    } else {
        location = -location - 1;
    }

    list.add( location, item );
    return location;
}