Java tutorial
package org.activityinfo.server.report.renderer.excel; /* * #%L * ActivityInfo Server * %% * Copyright (C) 2009 - 2013 UNICEF * %% * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as * published by the Free Software Foundation, either version 3 of the * License, or (at your option) any later version. * * 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 for more details. * * You should have received a copy of the GNU General Public * License along with this program. If not, see * <http://www.gnu.org/licenses/gpl-3.0.html>. * #L% */ import org.activityinfo.legacy.shared.reports.content.FilterDescription; import org.activityinfo.legacy.shared.reports.model.ReportElement; import org.apache.poi.ss.usermodel.*; import java.util.List; import java.util.logging.Logger; public abstract class BaseExcelRenderer<ElementT extends ReportElement> { private static final int MAX_CELL_CONTENT_LENGTH = 32700; protected final ElementT element; protected final Workbook book; protected final Sheet sheet; protected final CreationHelper factory; private static final Logger LOGGER = Logger.getLogger(BaseExcelRenderer.class.getName()); protected int rowIndex; public BaseExcelRenderer(Workbook book, ElementT element) { this.element = element; this.book = book; this.factory = book.getCreationHelper(); this.sheet = book.createSheet(composeSheetName()); /* Create title line */ Row titleRow = sheet.createRow(0); Cell titleCell = titleRow.createCell(0); titleCell.setCellValue(factory.createRichTextString(element.getTitle())); /* Create filter descriptors */ List<FilterDescription> descs = generateFilterDescriptions(); rowIndex = 2; for (FilterDescription desc : descs) { Row filterRow = sheet.createRow(rowIndex++); Cell filterCell = filterRow.createCell(0); String label = desc.joinLabels(", "); if (label.length() > MAX_CELL_CONTENT_LENGTH) { LOGGER.severe("Huge filter label string: " + label); label = label.substring(0, MAX_CELL_CONTENT_LENGTH) + "..."; } filterCell.setCellValue(factory.createRichTextString(label)); } rowIndex++; generate(); } public abstract List<FilterDescription> generateFilterDescriptions(); public String composeSheetName() { if (element.getSheetTitle() != null) { return element.getSheetTitle(); } else if (element.getTitle() != null) { return element.getTitle(); } else { return "Sheet" + (book.getNumberOfSheets() + 1); } } public void generate() { } protected Font createBaseFont() { Font font = book.createFont(); return font; } }