quick answer, Lucene only operates on strings (from a high level
perspective)
simon
On Fri, Sep 21, 2012 at 11:54 AM, 惠达 王 <wanghuida...@yahoo.cn> wrote:
> hi all:
> I want to know that why transform numeric to string?
>
> public static int longToPrefixCoded(final long val, final int shift,
> final BytesRef bytes) {
>
> if (shift>63 || shift<0)
>
> throw new IllegalArgumentException("Illegal shift value, must be
> 0..63");
>
> int hash, nChars = (63-shift)/7 + 1;
>
> bytes.offset = 0;
>
> bytes.length = nChars+1;
>
> if (bytes.bytes.length < bytes.length) {
>
> bytes.grow(NumericUtils.BUF_SIZE_LONG);//11
>
> }
>
> bytes.bytes[0] = (byte) (hash = (SHIFT_START_LONG + shift));
>
> long sortableBits = val ^ 0x8000000000000000L;
>
> sortableBits >>>= shift;
>
> while (nChars > 0) {
>
> // Store 7 bits per byte for compatibility
>
> // with UTF-8 encoding of terms
>
> bytes.bytes[nChars--] = (byte)(sortableBits & 0x7f);
>
> sortableBits >>>= 7;
>
> }
>
> // calculate hash
>
> for (int i = 1; i < bytes.length; i++) {
>
> hash = 31*hash + bytes.bytes[i];
>
> }
>
> return hash;
>
> }
>
>
> 王惠达 (PHP开发工程师, Sysdev Team)
> -------------------------
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