@Override
public void selectCells(GlobalIndex<Partition> gIndex, ResultCollector<Partition> output) {
int numPartitions;
if (gIndex.isReplicated()) {
// Need to process all partitions to perform duplicate avoidance
numPartitions = gIndex.rangeQuery(queryRange, output);
LOG.info("Selected " + numPartitions + " partitions overlapping " + queryRange);
} else {
Prism queryRange = this.queryRange.getMBR();
// Need to process only partitions on the perimeter of the query
// range
// Partitions that are totally contained in query range should
// not be
// processed and should be copied to output directly
numPartitions = 0;
for (Partition p : gIndex) {
if (queryRange.contains(p)) {
// TODO partitions totally contained in query range
// should be copied
// to output directly
// XXX Until hard links are supported, R-tree blocks are
// processed
// similar to R+-tree
output.collect(p);
numPartitions++;
} else if (p.isIntersected(queryRange)) {
output.collect(p);
numPartitions++;
}
}
LOG.info("Selected " + numPartitions + " partitions on the perimeter of " + queryRange);
}
}
/**
* Runs a range query on the local machine by iterating over the whole file.
*
* @param fs - FileSystem that contains input file
* @param file - path to the input file
* @param queryRange - The range to look in
* @param shape - An instance of the shape stored in file
* @param output - Output is sent to this collector. If <code>null</code>, output is not collected
* and only the number of results is returned.
* @return number of results found
* @throws IOException
*/
public static <S extends Shape> long rangeQueryLocal(
FileSystem fs, Path file, Shape queryRange, S shape, ResultCollector<S> output)
throws IOException {
long file_size = fs.getFileStatus(file).getLen();
ShapeRecordReader<S> shapeReader = new ShapeRecordReader<S>(fs.open(file), 0, file_size);
long resultCount = 0;
Prism cell = shapeReader.createKey();
while (shapeReader.next(cell, shape)) {
if (shape.isIntersected(queryRange)) {
boolean report_result;
if (cell.isValid()) {
// Check for duplicate avoidance
Prism intersection_mbr = queryRange.getMBR().getIntersection(shape.getMBR());
report_result =
cell.contains(intersection_mbr.t1, intersection_mbr.x1, intersection_mbr.y1);
} else {
report_result = true;
}
if (report_result) {
resultCount++;
if (output != null) {
output.collect(shape);
}
}
}
}
shapeReader.close();
return resultCount;
}