code: @Override
  	public FileInputSplit[] createInputSplits(int minNumSplits) throws IOException {
  		int numAvroFiles = 0;
  		final Path path = this.filePath;
  		// get all the files that are involved in the splits
  		final FileSystem fs = path.getFileSystem();
  		final FileStatus pathFile = fs.getFileStatus(path);
  
  		if (!acceptFile(pathFile)) {
  			throw new IOException("The given file does not pass the file-filter");
  		}
  		if (pathFile.isDir()) {
  			// input is directory. list all contained files
  			final FileStatus[] dir = fs.listStatus(path);
  			for (int i = 0; i < dir.length; i++) {
  				if (!dir[i].isDir() && acceptFile(dir[i])) {
  					numAvroFiles++;
  				}
  			}
  		} else {
  			numAvroFiles = 1;
  		}
  		return super.createInputSplits(numAvroFiles);
  	}
docs: Set minNumSplits to number of files.