content: /**
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   * <p>
   * http://www.apache.org/licenses/LICENSE-2.0
   * <p>
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.atlas.util;
  
  import com.opencsv.CSVReader;
  import com.opencsv.exceptions.CsvValidationException;
  import org.apache.atlas.AtlasErrorCode;
  import org.apache.atlas.exception.AtlasBaseException;
  import org.apache.commons.collections.CollectionUtils;
  import org.apache.commons.io.FilenameUtils;
  import org.apache.commons.lang.StringUtils;
  import org.apache.poi.hssf.usermodel.HSSFWorkbook;
  import org.apache.poi.ss.usermodel.Cell;
  import org.apache.poi.ss.usermodel.CellType;
  import org.apache.poi.ss.usermodel.Row;
  import org.apache.poi.ss.usermodel.Sheet;
  import org.apache.poi.ss.usermodel.Workbook;
  import org.apache.poi.xssf.usermodel.XSSFWorkbook;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.InputStreamReader;
  import java.util.ArrayList;
  import java.util.Iterator;
  import java.util.List;
  
  import static org.apache.atlas.repository.Constants.SupportedFileExtensions.CSV;
  import static org.apache.atlas.repository.Constants.SupportedFileExtensions.XLS;
  import static org.apache.atlas.repository.Constants.SupportedFileExtensions.XLSX;
  
  public class FileUtils {
      public static final String PIPE_CHARACTER   = "|";
      public static final String COLON_CHARACTER  = ":";
      public static final String ESCAPE_CHARACTER = "\\";
  
      //BusinessMetadata attributes association uploads
      public static final int TYPENAME_COLUMN_INDEX          = 0;
      public static final int UNIQUE_ATTR_VALUE_COLUMN_INDEX = 1;
      public static final int BM_ATTR_NAME_COLUMN_INDEX      = 2;
      public static final int BM_ATTR_VALUE_COLUMN_INDEX     = 3;
      public static final int UNIQUE_ATTR_NAME_COLUMN_INDEX  = 4;
  
      private FileUtils() {
          // to block instantiation
      }
  
      public static List<String[]> readFileData(String fileName, InputStream inputStream) throws AtlasBaseException {
          List<String[]> ret;
          String         extension = FilenameUtils.getExtension(fileName);
  
          if (extension.equalsIgnoreCase(CSV.name())) {
              ret = readCSV(inputStream);
          } else if (extension.equalsIgnoreCase(XLS.name()) || extension.equalsIgnoreCase(XLSX.name())) {
              ret = readExcel(inputStream, extension);
          } else {
              throw new AtlasBaseException(AtlasErrorCode.INVALID_FILE_TYPE, fileName);
          }
  
          if (CollectionUtils.isEmpty(ret)) {
              throw new AtlasBaseException(AtlasErrorCode.NO_DATA_FOUND);
          }
  
          return ret;
      }
  
      public static List<String[]> readCSV(InputStream inputStream) throws AtlasBaseException {
          List<String[]> ret = new ArrayList<>();
  
          try (CSVReader csvReader = new CSVReader(new InputStreamReader(inputStream))) {
              String[] header = csvReader.readNext();
  
              if (header == null || header.length == 0) {
                  return ret;
              }
  
              String[] data;
  
              while ((data = csvReader.readNext()) != null) {
                  if (data.length > 1) {
                      ret.add(data);
                  }
              }
          } catch (CsvValidationException | IOException e) {
              throw new AtlasBaseException(AtlasErrorCode.NOT_VALID_FILE, CSV.name());
          }
  
          return ret;
      }
  
      public static List<String[]> readExcel(InputStream inputStream, String extension) throws AtlasBaseException {
          List<String[]> ret = new ArrayList<>();
  
          try (Workbook excelBook = extension.equalsIgnoreCase(XLS.name()) ? new HSSFWorkbook(inputStream) : new XSSFWorkbook(inputStream)) {
              Sheet         excelSheet = excelBook.getSheetAt(0);
              Iterator<Row> itr        = excelSheet.rowIterator();
              Row           headerRow  = itr.next();
  
              if (isRowEmpty(headerRow)) {
                  return ret;
              }
  
              while (itr.hasNext()) {
                  Row row = itr.next();
  
                  if (!isRowEmpty(row)) {
                      String[] data = new String[row.getLastCellNum()];
  
                      for (int i = 0; i < row.getLastCellNum(); i++) {
                          data[i] = (row.getCell(i) != null) ? row.getCell(i).getStringCellValue().trim() : null;
                      }
  
                      ret.add(data);
                  }
              }
          } catch (IOException e) {
              throw new AtlasBaseException(AtlasErrorCode.NOT_VALID_FILE, XLS.name());
          }
  
          return ret;
      }
  
      public static String getBusinessMetadataHeaders() {
          List<String> bMHeader = new ArrayList<>();
  
          bMHeader.add("EntityType");
          bMHeader.add("EntityUniqueAttributeValue");
          bMHeader.add("BusinessAttributeName");
          bMHeader.add("BusinessAttributeValue");
          bMHeader.add("EntityUniqueAttributeName[optional]");
  
          return StringUtils.join(bMHeader, ",");
      }
  
      private static boolean isRowEmpty(Row row) {
          for (int c = row.getFirstCellNum(); c < row.getLastCellNum(); c++) {
              Cell cell = row.getCell(c);
  
              if (cell != null && cell.getCellType() != CellType.BLANK) {
                  return false;
              }
          }
  
          return true;
      }
  }
  