package com.opencsv;
   
   import java.io.IOException;
   import java.io.PrintWriter;
   import java.io.Writer;
   import java.sql.ResultSet;
   import java.sql.SQLException;
   
   /**
   * The AbstractCSVWriter was created to prevent duplication of code between the CSVWriter and the
   * CSVParserWriter classes.
   *
   * @since 4.2
   */
  public abstract class AbstractCSVWriter implements ICSVWriter {
  
      private final Writer writer;
      private final String lineEnd;
      private ResultSetHelper resultService;
      protected volatile IOException exception;
  
      /**
       * Constructor to initialize the common values.
       *
       * @param writer  Writer used for output of csv data.
       * @param lineEnd String to append at end of data (either "\n" or "\r\n").
       */
      protected AbstractCSVWriter(Writer writer, String lineEnd) {
          this.writer = writer;
          this.lineEnd = lineEnd;
      }
  
      /**
       * Provides access to the writer used for outputting CSV data.
       *
       * @return The {@link Writer} instance used for writing CSV content.
       */
      protected final Writer getWriter() {
          return writer;
      }
  
      /**
       * Retrieves the line ending sequence used when writing CSV data.
       *
       * @return The line ending sequence, either "\n" or "\r\n".
       */
      protected final String getLineEnd() {
          return lineEnd;
      }
  
      @Override
      public void writeAll(Iterable<String[]> allLines, boolean applyQuotesToAll) {
          StringBuilder sb = new StringBuilder(INITIAL_STRING_SIZE);
          try {
              for (String[] line : allLines) {
                  writeNext(line, applyQuotesToAll, sb);
                  sb.setLength(0);
              }
          } catch (IOException e) {
              exception = e;
          }
      }
  
      /**
       * Writes the column names.
       *
       * @param rs               ResultSet containing column names.
       * @param applyQuotesToAll Whether all header names should be quoted.
       * @throws SQLException Thrown by {@link ResultSetHelper#getColumnNames(java.sql.ResultSet)}
       */
      protected void writeColumnNames(ResultSet rs, boolean applyQuotesToAll) throws SQLException {
          writeNext(resultService().getColumnNames(rs), applyQuotesToAll);
      }
  
      @Override
      public int writeAll(ResultSet rs, boolean includeColumnNames, boolean trim, boolean applyQuotesToAll) throws SQLException, IOException {
          int linesWritten = 0;
  
          if (includeColumnNames) {
              writeColumnNames(rs, applyQuotesToAll);
              linesWritten++;
          }
  
          while (rs.next()) {
              writeNext(resultService().getColumnValues(rs, trim), applyQuotesToAll);
              linesWritten++;
          }
  
          return linesWritten;
      }
  
      @Override
      public void writeNext(String[] nextLine, boolean applyQuotesToAll) {
          try {
              writeNext(nextLine, applyQuotesToAll, new StringBuilder(INITIAL_STRING_SIZE));
          } catch (IOException e) {
              exception = e;
          }
      }
 
     /**
      * Writes the next line to the file.  This method is a fail-fast method that will throw the
      * IOException of the writer supplied to the CSVWriter (if the Writer does not handle the exceptions itself like
      * the PrintWriter class).
      *
      * @param nextLine         a string array with each comma-separated element as a separate
      *                         entry.
      * @param applyQuotesToAll true if all values are to be quoted.  false applies quotes only
      *                         to values which contain the separator, escape, quote or new line characters.
      * @param appendable       Appendable used as buffer.
      * @throws IOException Exceptions thrown by the writer supplied to CSVWriter.
      */
     protected abstract void writeNext(String[] nextLine, boolean applyQuotesToAll, Appendable appendable) throws IOException;
 
     @Override
     public void flush() throws IOException {
         writer.flush();
     }
 
     @Override
     public void close() throws IOException {
         flush();
         writer.close();
     }
 
     @Override
     public boolean checkError() {
 
         if (writer instanceof PrintWriter) {
             PrintWriter pw = (PrintWriter) writer;
             return pw.checkError();
         }
         if (exception != null) {  // we don't want to lose the original exception
             flushQuietly();  // checkError in the PrintWriter class flushes the buffer so we shall too.
         } else {
             try {
                 flush();
             } catch (IOException ioe) {
                 exception = ioe;
             }
         }
         return exception != null;
     }
 
     @Override
     public IOException getException() {
         return exception;
     }
 
     @Override
     public void resetError() {
         exception = null;
     }
 
     @Override
     public void setResultService(ResultSetHelper resultService) {
         this.resultService = resultService;
     }
 
     /**
      * Lazy resultSetHelper creation.
      *
      * @return Instance of resultSetHelper
      */
     protected ResultSetHelper resultService() {
         if (resultService == null) {
             resultService = new ResultSetHelperService();
         }
         return resultService;
     }
 }