DAO.java

package org.kvj.lima1.pg.sync.data;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.http.HttpServlet;
import javax.sql.DataSource;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.mchange.v2.c3p0.ComboPooledDataSource;

public class DAO {

	private static Logger log = LoggerFactory.getLogger(DAO.class);
	public static final String DATASOURCE_ATTR = "dataSource";

	private static final String ENV_DB_HOST = "OPENSHIFT_DB_HOST";
	private static final String ENV_DB_PORT = "OPENSHIFT_DB_PORT";
	private static final String ENV_DB_USERNAME = "OPENSHIFT_DB_USERNAME";
	private static final String ENV_DB_PASSWORD = "OPENSHIFT_DB_PASSWORD";
	private static final String ENV_DB_URL = "OPENSHIFT_DB_URL";
	private static final String ENV_DATA_DIR = "OPENSHIFT_DATA_DIR";

	public static DataSource initServet(ServletConfig config) {
		try {
			ComboPooledDataSource dataSource = new ComboPooledDataSource();
			dataSource.setDriverClass("org.postgresql.Driver");
			String url = String.format("jdbc:postgresql://%s:%s/%s",
					System.getenv(ENV_DB_HOST), System.getenv(ENV_DB_PORT),
					System.getenv(ENV_DB_URL));
			dataSource.setJdbcUrl(url);
			dataSource.setUser(System.getenv(ENV_DB_USERNAME));
			dataSource.setPassword(System.getenv(ENV_DB_PASSWORD));
			dataSource.setMinPoolSize(3);
			dataSource.setMaxPoolSize(10);
			dataSource.setAutoCommitOnClose(false);
			config.getServletContext()
					.setAttribute(DATASOURCE_ATTR, dataSource);
			log.info(String.format("DataSource created: %s, %s, %s",
					dataSource.getJdbcUrl(), dataSource.getUser(),
					dataSource.getPassword()));
			return dataSource;
		} catch (Exception e) {
			log.error("Error creating datasource", e);
		}
		return null;
	}

	public static void closeConnection(Connection c) {
		if (null != c) {
			try {
				c.close();
			} catch (Exception e) {
			}
		}
	}

	public static long nextID(Connection c) throws SQLException {
		PreparedStatement st = c.prepareStatement("select nextval('ids')");
		ResultSet set = st.executeQuery();
		set.next();
		return set.getLong(1);
	}

	public static DataSource getDataSource(ServletContext context) {
		try {
			return (DataSource) context.getAttribute(DATASOURCE_ATTR);
		} catch (Exception e) {
			return null;
		}
	}

	public static void destroyServlet(HttpServlet servlet) {
		ComboPooledDataSource dataSource = (ComboPooledDataSource) getDataSource(servlet
				.getServletContext());
		if (null != dataSource) {
			try {
				dataSource.close();
				log.info("DataSource closed");
			} catch (Exception e) {
				log.error("Error closing datasource", e);
			}
		}
	}

	public static File getUploadFolder(String name) throws IOException {
		String folderName = System.getenv(ENV_DATA_DIR);
		if (null == folderName) {
			folderName = System.getenv("user.home");
		}
		File folder = new File(folderName);
		if (!folder.exists() || !folder.isDirectory()) {
			throw new IOException("Data folder " + folderName
					+ " is not accessible");
		}
		File dataFolder = new File(folder, name);
		if (dataFolder.exists()) {
			if (dataFolder.isDirectory()) {
				return dataFolder;
			}
			throw new IOException("Data folder is not directory");
		} else {
			if (dataFolder.mkdir()) {
				return dataFolder;
			}
			throw new IOException("Data folder mkdir failed");
		}
	}

	public static void copyStream(InputStream in, OutputStream out)
			throws IOException {
		byte[] buffer = new byte[1024];
		BufferedInputStream bis = new BufferedInputStream(in, buffer.length);
		int bytes = 0;
		while ((bytes = bis.read(buffer)) > 0) {
			out.write(buffer, 0, bytes);
		}
	}
}