static ParquetMetadata mergeFooters(Path root, List<Footer> footers) {
String rootPath = root.toUri().getPath();
GlobalMetaData fileMetaData = null;
List<BlockMetaData> blocks = new ArrayList<BlockMetaData>();
for (Footer footer : footers) {
String footerPath = footer.getFile().toUri().getPath();
if (!footerPath.startsWith(rootPath)) {
throw new ParquetEncodingException(
footerPath + " invalid: all the files must be contained in the root " + root);
}
footerPath = footerPath.substring(rootPath.length());
while (footerPath.startsWith("/")) {
footerPath = footerPath.substring(1);
}
fileMetaData = mergeInto(footer.getParquetMetadata().getFileMetaData(), fileMetaData);
for (BlockMetaData block : footer.getParquetMetadata().getBlocks()) {
block.setPath(footerPath);
blocks.add(block);
}
}
return new ParquetMetadata(fileMetaData.merge(), blocks);
}