I have rather a simple portlet which displays the number of visitors of portal (online, daily, weekly, monthly, annually).
In the portlet class in doView method firstly I call one method which do an insert to the table (info about a new visitor). After I call 5 methods one by one which do a count select on the same table. They are all pretty similar, only their queries differ. One of the methods implementation is the following:
public static Integer getOnline() {
Integer res = null;
Statement stmt = null;
ResultSet rs = null;
try {
stmt = getConnection().createStatement();
rs = stmt.executeQuery(query);
if (rs.next()) {
res = new Integer(rs.getString("1"));
}
} catch (SQLException e) {
log.error("Excepton: " + e);
} finally {
if (rs != null) {
try { rs.close(); } catch (SQLException e) { log.warn("Error closing result set: ", e); }
rs = null;
}
if (stmt != null) {
try { stmt.close(); } catch (SQLException e) { log.warn("Error closing statement: ", e); }
stmt = null;
}
}
return res;
}
Connection is obtained:
public static Connection getConnection() {
try {
if (connection == null) {
if (dataSource == null) {
dataSource = (DataSource) new InitialContext().lookup(dataSourceName);
}
connection = dataSource.getConnection();
}
} catch (Exception e) {
log.error("Error on opening a connection: ", e);
}
return connection;
}
Connection is closed in the end of doView method. Occasionally I'm getting that exception:
com.ibm.db2.jcc.am.SqlException: [jcc][t4][10120][10898][4.14.88] Invalid operation: result set is closed. ERRORCODE=-4470, SQLSTATE=null
from one or few of the methods which do select. Also the following errors sometimes:
com.ibm.websphere.ce.cm.ObjectClosedException: DSRA9110E: Connection is closed.
com.ibm.websphere.ce.cm.ObjectClosedException: DSRA9110E: Statement is closed.
After searching the internet I still haven't found/realized what is the cause of an error in my case and how I can fix it. Any help would be appreciated.
