org.databene.formats.xls.BeanXLSWriter.java Source code

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Here is the source code for org.databene.formats.xls.BeanXLSWriter.java

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/*
 * Copyright (C) 2011-2015 Volker Bergmann (volker.bergmann@bergmann-it.de).
 * All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * http://www.apache.org/licenses/LICENSE-2.0
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.databene.formats.xls;

import java.io.Closeable;
import java.io.FileNotFoundException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFDataFormat;
import org.apache.poi.hssf.usermodel.HSSFRichTextString;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.CellStyle;
import org.databene.commons.ConfigurationError;
import org.databene.commons.IOUtil;
import org.databene.commons.bean.PropertyGraphAccessor;
import org.databene.commons.converter.ToStringConverter;

/**
 * Saves JavaBeans in MS Excel(TM) files.
 * Created: 27.12.2015 07:40:49
 * @since 1.0.7
 * @author Volker Bergmann
 */

public class BeanXLSWriter<E> implements Closeable {

    // attributes ------------------------------------------------------------------------------------------------------

    private final OutputStream out;
    private String sheetName;
    private List<PropFormat> beanProperties;

    private HSSFWorkbook workbook;

    // constructors ----------------------------------------------------------------------------------------------------

    public BeanXLSWriter(OutputStream out, String sheetName) {
        this(out, sheetName, null);
    }

    public BeanXLSWriter(OutputStream out, String sheetName, List<PropFormat> beanProperties) {
        this.out = out;
        this.sheetName = sheetName;
        this.beanProperties = (beanProperties != null ? new ArrayList<PropFormat>(beanProperties)
                : new ArrayList<PropFormat>());
    }

    public void addProperty(PropFormat property) {
        this.beanProperties.add(property);
    }

    public void save(E bean) {
        HSSFSheet sheet = getOrCreateSheet(bean, sheetName);
        HSSFRow row = sheet.createRow(sheet.getLastRowNum() + 1);
        for (int i = 0; i < beanProperties.size(); i++) {
            PropFormat prop = beanProperties.get(i);
            Object propValue = PropertyGraphAccessor.getPropertyGraph(prop.getName(), bean);
            render(propValue, row, i);
        }
    }

    @Override
    public void close() {
        try {
            if (workbook == null)
                workbook = new HSSFWorkbook(); // if no data was added, create an empty Excel document
            else
                XLSUtil.autoSizeColumns(workbook);
            // Write the output
            workbook.write(out);
        } catch (FileNotFoundException e) {
            throw new ConfigurationError(e);
        } catch (Exception e) {
            throw new RuntimeException(e);
        } finally {
            IOUtil.close(out);
        }
    }

    // private helpers -------------------------------------------------------------------------------------------------

    private HSSFSheet getOrCreateSheet(E bean, String sheetName) {
        // create file
        if (workbook == null)
            createWorkbook();
        HSSFSheet sheet = workbook.getSheet(sheetName);
        if (sheet == null) {
            sheet = workbook.createSheet(sheetName);
            writeHeaderRow(bean, sheet);
        }
        return sheet;
    }

    private void createWorkbook() {
        this.workbook = new HSSFWorkbook();
    }

    private void writeHeaderRow(E bean, HSSFSheet sheet) {
        HSSFRow headerRow = sheet.createRow(0);
        for (int i = 0; i < beanProperties.size(); i++) {
            PropFormat prop = beanProperties.get(i);
            // write column header
            String componentName = prop.getName();
            headerRow.createCell(i).setCellValue(new HSSFRichTextString(componentName));
            // apply pattern
            if (prop.getPattern() != null) {
                HSSFDataFormat dataFormat = workbook.createDataFormat();
                CellStyle columnStyle = workbook.createCellStyle();
                columnStyle.setDataFormat(dataFormat.getFormat(prop.getPattern()));
                sheet.setDefaultColumnStyle(i, columnStyle);
            }
        }
    }

    private static void render(Object propValue, HSSFRow row, int column) {
        HSSFCell cell = row.createCell(column);
        if (propValue instanceof Number)
            cell.setCellValue(((Number) propValue).doubleValue());
        else if (propValue instanceof Date)
            cell.setCellValue((Date) propValue);
        else if (propValue instanceof Boolean)
            cell.setCellValue((Boolean) propValue);
        else {
            String s = ToStringConverter.convert(propValue, null);
            cell.setCellValue(new HSSFRichTextString(s));
        }
    }

    // java.lang.Object overrides --------------------------------------------------------------------------------------

    @Override
    public String toString() {
        return getClass().getSimpleName();
    }

}