source 'https://dl.bintray.com/colisweb/maven'

jar 'com.colisweb:JRubyConcurrentConstantMemoryExcel_2.12', '1.0.4'

require 'java'

java_import 'com.colisweb.jruby.concurrent.constant.memory.excel.ConcurrentConstantMemoryExcel'
java_import 'com.colisweb.jruby.concurrent.constant.memory.excel.Cell'

header     = ["A", "B", "C"].to_java(:string)
sheet_name = "cars"

# Curently, support only one sheet per workbook.
# 
workbook_state = ConcurrentConstantMemoryExcel.newWorkbookState(sheet_name, header)

to_parametrize_compute_rows_lambda = 
  ->(query) {
    ->() {
      rows = query.execute # example of an expensive query that fetches the rows data
        
      # Example of conversion of data to Cell.
      #
      # For now, only blank, string and numeric cells are supported.   
      # 
      rows.map { |row|
        row.map { |cell_data|
          if cell_data.nil?
            ConcurrentConstantMemoryExcel.blankCell
          elsif cell_data.is_a?(String)
            ConcurrentConstantMemoryExcel.stringCell(cell_data)
          elsif cell_data.is_a?(Fixnum)
            ConcurrentConstantMemoryExcel.numericCell(cell_data.to_f)
          else
            raise "For now, unsupported Cell type"
          end
        }
      }
    }
  }

# Here, we assume that the `queries` are sorted in the order we want the data to be ordered in the final xlsx file.
# 
# You can control in which order the data is written thanks to the last argument of the `ConcurrentConstantMemoryExcel.addRows` function.
# 
queries.each_with_index { |query, index|

  compute_rows_lambda = to_parametrize_compute_rows_lambda.call(query)

  # Do not launch any computation. It just registers required computations in the `workbook_state`.
  #
  # The second argument for this function call should be a lambda taking no parameter.   
  # 
  ConcurrentConstantMemoryExcel.addRows(workbook_state, compute_rows_lambda, index.to_java(:int))
  
}

# Computations of rows will really begin with this function call. Not before.
# 
ConcurrentConstantMemoryExcel.writeFile(workbook_state, "path/to/my/file") # will write a file named `file.xlsx` in the `path/to/my` directory.