CSVExporter.java

/*
Copyright (C) 2010 Haowen Ning

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 2
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, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

*/
package org.liberty.android.fantastischmemo.converter;

import com.opencsv.CSVWriter;

import org.liberty.android.fantastischmemo.common.AnyMemoDBOpenHelper;
import org.liberty.android.fantastischmemo.common.AnyMemoDBOpenHelperManager;
import org.liberty.android.fantastischmemo.dao.CardDao;
import org.liberty.android.fantastischmemo.dao.CategoryDao;
import org.liberty.android.fantastischmemo.entity.Card;

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.List;
import java.util.concurrent.Callable;

public class CSVExporter implements Converter {

    private static final long serialVersionUID = 1766409315203795426L;

    /* Null is for default separator "," */
    private Character separator = null;

    public CSVExporter() {
        separator = ',';
    }

    public CSVExporter(char separator) {
        this.separator = separator;
    }

    @Override
    public void convert(String src, String dest) throws Exception {
        new File(dest).delete();

        AnyMemoDBOpenHelper helper = AnyMemoDBOpenHelperManager.getHelper(src);
        final CardDao cardDao = helper.getCardDao();
        final CategoryDao categoryDao = helper.getCategoryDao();

        CSVWriter writer;
        if (separator == null) {
            writer = new CSVWriter(new FileWriter(dest));
        } else {
            writer = new CSVWriter(new FileWriter(dest), separator);
        }
        try {
            final List<Card> cardList = cardDao.queryForAll();

            // Populate all category field in a transaction.
            categoryDao.callBatchTasks(new Callable<Void>() {
                public Void call() throws Exception {
                    for (Card c: cardList) {
                        categoryDao.refresh(c.getCategory());
                    }
                    return null;
                }
            });
            AnyMemoDBOpenHelperManager.releaseHelper(helper);
            if(cardList.size() == 0){
                throw new IOException("Can't retrieve cards for database: " + src);
            }
            String[] entries = new String[4];
            for(Card card: cardList) {
                entries[0] = card.getQuestion();
                entries[1] = card.getAnswer();
                entries[2] = card.getCategory().getName();
                entries[3] = card.getNote();
                writer.writeNext(entries);
            }
        } finally {
            writer.close();
        }
    }

    @Override
    public String getSrcExtension() {
        return "db";
    }

    @Override
    public String getDestExtension() {
        return "csv";
    }
}