Factory Pattern ~ A Modern Approach - 3

FileOperations.java

public class FileOperations {
  private FileReaderFactory readerFactory;
  
  // some code here
  
  public String readFile(String filePath){
    return readerFactory.createFileReader(filePath).readFile(FilePath);
  }
}

FileReaderFactory.java

public class FileReaderFactory {
  // other necessary methods are here
  
  public FileReader createFileReader(String filePath) {
    FileReader reader;
    
    if (isExcelFile(filePath)) {
      reader = new ExcelReader();
    }
    else if(isPdfFile(filePath)) {
      reader = new PdfReader();
    }
    else if(isCsvFile(filePath)) {
      reader = new CsvReader();
    }
    else {
      throw new UnsupportedFileException("...");
    }
  
    return reader;
  }
}