Android中SparseArray

SparseArray是android裡為<Interger,Object>這樣的Hashmap而專門寫的class,目的是提高效率，其核心是折半尋找函數（binarySearch），今天在看這個class的實現時發現一個很好的設計：  
 
    public void remove(int key) {
        delete(key);
    }
remove和delete都實現了，功能當然是一樣的.
起折半尋找演算法也寫的非常棒：
    private static int binarySearch(int[] a, int start, int len, int key) {
        int high = start + len, low = start - 1, guess;

        while (high - low > 1) {
            guess = (high + low) / 2;

            if (a[guess] < key)
                low = guess;
            else
                high = guess;
        }

        if (high == start + len)
            return ~(start + len);
        else if (a[high] == key)
            return high;
        else
            return ~high;
    }