com.siemens.sw360.exporter.ExcelExporter.java Source code

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Here is the source code for com.siemens.sw360.exporter.ExcelExporter.java

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/*
 * Copyright Siemens AG, 2014-2015. Part of the SW360 Portal Project.
 *
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License Version 2.0 as published by the
 * Free Software Foundation with classpath exception.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License version 2.0 for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program (please see the COPYING file); if not, write to the Free
 * Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 */
package com.siemens.sw360.exporter;

import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.XSSFCellStyle;
import org.apache.poi.xssf.usermodel.XSSFFont;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;

/**
 * Created on 06/02/15.
 *
 * @author cedric.bodet@tngtech.com
 */
public class ExcelExporter<T> {

    private final ExporterHelper<T> helper;

    private final int nColumns;

    public ExcelExporter(ExporterHelper<T> helper) {
        this.helper = helper;
        nColumns = helper.getColumns();
    }

    public InputStream makeExcelExport(List<T> documents) throws IOException {
        final Workbook workbook = new XSSFWorkbook();

        Sheet sheet = workbook.createSheet("Component Data");

        /** Adding styles to cells */
        CellStyle cellStyte = createCellStyte(workbook);
        CellStyle headerStyle = createHeaderStyle(workbook);

        /** Create header row */
        Row headerRow = sheet.createRow(0);
        List<String> headerNames = helper.getHeaders();
        fillRow(headerRow, headerNames, headerStyle);

        /** Create data rows */
        fillValues(sheet, documents, cellStyte);

        /** Resize the columns */
        for (int iColumns = 0; iColumns < nColumns; iColumns++) {
            sheet.autoSizeColumn(iColumns);
        }

        /** Copy the streams */
        final ByteArrayOutputStream out = new ByteArrayOutputStream();
        workbook.write(out);

        return new ByteArrayInputStream(out.toByteArray());
    }

    /**
     * Convert all documents to
     */
    private void fillValues(Sheet sheet, List<T> documents, CellStyle style) {
        int nRow = documents.size();
        for (int iRow = 0; iRow < nRow; iRow++) {
            T document = documents.get(iRow);
            List<String> values = helper.makeRow(document);
            Row row = sheet.createRow(iRow + 1); // Since 0 is used for headers
            fillRow(row, values, style);
        }
    }

    /**
     * Write the values into the row, setting the cells to the given style
     */
    private void fillRow(Row row, List<String> values, CellStyle style) {
        for (int column = 0; column < nColumns; column++) {
            Cell cell = row.createCell(column);
            cell.setCellValue(values.get(column));
            cell.setCellStyle(style);
        }
    }

    /**
     * Create style for data cells
     */
    private static CellStyle createCellStyte(Workbook workbook) {
        CellStyle cellStyle = workbook.createCellStyle();
        cellStyle.setBorderBottom(XSSFCellStyle.BORDER_THIN);
        cellStyle.setBorderTop(XSSFCellStyle.BORDER_THIN);
        cellStyle.setBorderRight(XSSFCellStyle.BORDER_THIN);
        cellStyle.setBorderLeft(XSSFCellStyle.BORDER_THIN);
        return cellStyle;
    }

    /**
     * Create header style, same has cell style but with bold font
     */
    private static CellStyle createHeaderStyle(Workbook workbook) {
        CellStyle headerCellStyle = createCellStyte(workbook);
        Font font = workbook.createFont();
        font.setBoldweight(XSSFFont.BOLDWEIGHT_BOLD);
        headerCellStyle.setFont(font);
        return headerCellStyle;
    }

}