Jessie,
I've been optimizing the PostGIS driver, and I speeded up the reading of
a set of coordinates. I use the ObjectInputStream.bytesToDoubles()
NATIVE function which takes a byte[] and writes to a double[]. You can
probably do the same thing with the shapefile driver. On my test of
100,000 lines (average 83 points/line) this was about 15% faster than
the pure java version, and I bet it will be even faster for geometries
with larger number of coordinates.
If you want, I can send you a shapefile with lots of points in each
geometry.
dave
static Method bytesToDoublesMethod = null;
static Object[] bytesToDoublesMethodArgs = new Object[5];
static
{
try{
bytesToDoublesMethod =
ObjectInputStream.class.getDeclaredMethod("bytesToDoubles",new Class[]
{byte[].class,int.class,double[].class,int.class,int.class} );
bytesToDoublesMethod.setAccessible(true);
}
catch(Exception e)
{
bytesToDoublesMethod=null;
}
}
private final CoordinateSequence readCoordinateSequence(int size)
throws IOException
{
// problem?
if (bytesToDoublesMethod == null)
return readCoordinateSequencePureJava(size);
try{
double[] ords = new double[size*2];
bytesToDoublesMethodArgs[0] = bytes; // can be done once
bytesToDoublesMethodArgs[1] = new Integer(index);
bytesToDoublesMethodArgs[2] =ords;
bytesToDoublesMethodArgs[3] = new Integer(0); // can be
done once
bytesToDoublesMethodArgs[4] = new Integer(size*2);
bytesToDoublesMethod.invoke(null,bytesToDoublesMethodArgs);
index += 8*2*size;
return coordFactory.create(ords);
}
catch(Exception e)
{
e.printStackTrace();
return readCoordinateSequencePureJava(size);
}
}
private final CoordinateSequence readCoordinateSequencePureJava(int
size) throws IOException
{
LiteCoordinateSequence seq =
(LiteCoordinateSequence)coordFactory.create(size, 2);
double[] ords = seq.getArray();
for (int i = 0; i < size; i++)
{
long longvalue = (long) (bytes[index] & 0xff) << 56
| (long) (bytes[index+1] & 0xff) << 48
| (long) (bytes[index+2] & 0xff) << 40
| (long) (bytes[index+3] & 0xff) << 32
| (long) (bytes[index+4] & 0xff) << 24
| (long) (bytes[index+5] & 0xff) << 16
| (long) (bytes[index+6] & 0xff) << 8
| (long) (bytes[index+7] & 0xff);
index +=8;
ords[i*2]= Double.longBitsToDouble(longvalue);
longvalue = (long) (bytes[index] & 0xff) << 56
| (long) (bytes[index+1] & 0xff) << 48
| (long) (bytes[index+2] & 0xff) << 40
| (long) (bytes[index+3] & 0xff) << 32
| (long) (bytes[index+4] & 0xff) << 24
| (long) (bytes[index+5] & 0xff) << 16
| (long) (bytes[index+6] & 0xff) << 8
| (long) (bytes[index+7] & 0xff);
index +=8;
ords[i*2+1]= Double.longBitsToDouble(longvalue);
}
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