lesaint / poi-wrapper

A small wrapping layer around POI which makes POI coding more readeable

poi-wrapper

A small wrapping layer around POI which makes creating OOXML Excel files with POI more readeable.

Goal

By introducing various object and utility classes, this project aims at :

1. separating describing styles/font/dataformat from actually creating them
2. provide a readable way of creating cells and merged region in code (class to a DSL)

This allows factorize, reuse styles/font/border/dataformat in code and drastically reduce code duplication.

These informations can even be static, allowing the use of constants and static imports drastically improving code readibility.

• Build Status:

Limitations

This project is available as is and does not provides an extensive support of all styles/font/border/dataformat properties.

It only contains features that I had to use in a project of mine.

That said, the project is open source, feel free to fork or contribute to improve it.

• Issues: https://github.com/mycila/license-maven-plugin/issues

Documentation

The main entry point of using this wrapper is the CellCreator class and its createCell static methods.

With the right static imports, creating a merged region with a border, a specific font and a format can be as consise and readable as the following example.

createCell(region(row, K, 14, L), totalPrice, black11CenterWhite, ALL_MEDIUM_BORDER, CURRENCY);

creates a region spanning from cell 12-K to 14-L, with a medium border all around it, in Arial 11, containing the total price formatted with excel default currency format

Please find below the relevant code requiered to achieve the writting of the code line above. It may seem like a lot of code for a single cell, but there isn't many other lines imports required to create dozens of other cells.

import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

import static fr.javatronic.poiwrapper.Border.ALL_MEDIUM_BORDER;
import static fr.javatronic.poiwrapper.CellCreator.createCell;
import static fr.javatronic.poiwrapper.DataFormats.CURRENCY;
import static fr.javatronic.poiwrapper.MergedRegionFactory.region;
import static fr.javatronic.poiwrapper.Column.K;
import static fr.javatronic.poiwrapper.Column.L;
import static fr.javatronic.poiwrapper.SheetWrapper.create;
import static org.apache.poi.hssf.usermodel.HSSFFont.FONT_ARIAL;
import static org.apache.poi.ss.usermodel.CellStyle.ALIGN_CENTER;
import static org.apache.poi.ss.usermodel.IndexedColors.BLACK;

[...]
    CellStyleDescriptor black11CenterWhite = CellStyleDescriptor.builder()
      .withFontName(FONT_ARIAL)
      .withFontSize(11)
      .withAlignH(ALIGN_CENTER)
      .withFgColor(BLACK)
      .build();

    Workbook wb = new XSSFWorkbook();
    SheetWrapper sheet = create(wb, "Name of the sheet here");
    Row row = sheet.getOrCreateRow(12);
    float totalPrice = computeTotalPrice();
    createCell(region(row, K, 14, L), totalPrice, black11CenterWhite, ALL_MEDIUM_BORDER, CURRENCY);

[...]

poi-wrapper's Issues

create a FontDescriptor object

It is not currently possible to factorise Font description when creating multiple CellStyleDescriptor which only difference is the text alignment, for example.

Introducing a FontDescriptor class could help on that part.

move CellCreator#createCell methods to SheetWrapper and delete CellCreator

Moving these methods to SheetWrapper will be a way of saving on having to call SheetWrapper#getOrCreateRow all the time.

In addition, it will save us from the Helper pattern implemented by CellCreator.

Code such as the following :

Row row = sheet.getOrCreateRow(12);
createCell(region(row, K, 14, L), totalPrice, black11CenterWhite, ALL_MEDIUM_BORDER, CURRENCY);

Could be replaced with :

createCell(region(12, K, 14, L), totalPrice, black11CenterWhite, ALL_MEDIUM_BORDER, CURRENCY);

This change requires to change the type of row property of class MergedRegion from a Row to an int.