ExportQuery.java

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/*
 * Turró i Cutiller Foundation. License notice.
 * Copyright (C) 2011 Lluis Turró Cutiller <http://www.turro.org/>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package  org.turro.jpa.export;
 
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Collection;
import java.util.Date;
import java.util.logging.Level;
import java.util.logging.Logger;
import jxl.Workbook;
import jxl.write.DateTime;
import jxl.write.Label;
import jxl.write.WritableSheet;
import jxl.write.WritableWorkbook;
import jxl.write.WriteException;
import org.turro.elephant.context.ElephantContext;
 
public class ExportQuery {
 
  private final Collection<String> columns;
  private final Collection<Object[]> results;
 
  public ExportQuery(Collection<String> columns, Collection<Object[]> results) {
    this.columns = columns;
    this.results = results;
  }
 
  public InputStream getExcel(String sheetName) {
    try {
      ByteArrayOutputStream baos = new ByteArrayOutputStream();
      WritableWorkbook ww = Workbook.createWorkbook(baos);
      WritableSheet ws = ww.createSheet(sheetName, 0);
      writeSheet(ws);
      ww.write();
      ww.close();
      baos.close();
      return new ByteArrayInputStream(baos.toByteArray());
    } catch (WriteException | IOException ex) {
      Logger.getLogger(ExportQuery.class.getName()).log(Level.SEVERE, ElephantContext.logMsg(null), ex);
    }
    return null;
  }
 
  private void writeSheet(WritableSheet ws) throws WriteException {
    int countCols = 0, countRows = 0;
    for(String s : columns) {
      ws.addCell(new Label(countCols++, countRows, s));
    }
    for(Object[] objs : results) {
      countCols = 0;
      countRows++;
      for(Object obj : objs) {
        if(obj instanceof Number) {
          ws.addCell(new jxl.write.Number(countCols++, countRows, 
                  ((Number)obj).doubleValue()));
        } else if(obj instanceof Date) {
          ws.addCell(new DateTime(countCols++, countRows, (Date) obj));
        } else {
          ws.addCell(new Label(countCols++, countRows, (String) obj));
        }
      }
    }
  }
 
}