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yacy_search_server/source/net/yacy/document/content/dao/DatabaseConnection.java

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3.4 KiB

// DatabaseConnection.java
// (C) 2009 by Michael Peter Christen; mc@yacy.net, Frankfurt a. M., Germany
// first published 11.06.2009 on http://yacy.net
//
// $LastChangedDate$
// $LastChangedRevision$
// $LastChangedBy$
//
// LICENSE
//
// 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 net.yacy.document.content.dao;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import net.yacy.cora.util.ConcurrentLog;
public class DatabaseConnection {
private Connection connection;
public DatabaseConnection(final String dbType, String host, int port, String dbname, String user, String pw) throws SQLException {
String dbDriverStr = null, dbConnStr = null;
if (dbType.equalsIgnoreCase("mysql")) {
dbDriverStr = "com.mysql.jdbc.Driver";
dbConnStr = "jdbc:mysql://" + host + ":" + port + "/" + dbname;
} else if (dbType.equalsIgnoreCase("pgsql")) {
dbDriverStr = "org.postgresql.Driver";
dbConnStr = "jdbc:postgresql://" + host + ":" + port + "/" + dbname;
} else throw new IllegalArgumentException();
try {
Class.forName(dbDriverStr).newInstance();
} catch (final Exception e) {
throw new SQLException("Unable to load the jdbc driver: " + e.getMessage());
}
try {
this.connection = DriverManager.getConnection(dbConnStr, user, pw);
} catch (final Exception e) {
throw new SQLException("Unable to establish a database connection: " + e.getMessage());
}
}
public void setAutoCommit(boolean b) {
try {
this.connection.setAutoCommit(b);
} catch (final SQLException e) {
ConcurrentLog.logException(e);
}
}
public int count(String tablename) throws SQLException {
Statement stmt = null;
ResultSet rs = null;
try {
stmt = this.connection.createStatement();
rs = stmt.executeQuery("select count(*) from " + tablename);
if (rs.next()) {
return rs.getInt(1);
}
return 0;
} catch (final SQLException e) {
throw e;
} finally {
if (rs != null) try {rs.close();} catch (final SQLException e) {}
if (stmt != null) try {stmt.close();} catch (final SQLException e) {}
}
}
public synchronized void close() {
if (connection != null) {
try {
connection.close();
connection = null;
} catch (final SQLException e) {
}
}
}
public Statement statement() throws SQLException {
return this.connection.createStatement();
}
}