I have an EJB, which has @TransactionAttribute(TransactionAttributeType.REQUIRES_NEW). Inside EJB I have a logger, which has been configured to log into a database using JNDI appender and JDBC:
public class JNDIAppender extends AppenderSkeleton {
private Connection connection;
private Statement statement;
private String sql;
private String dataSourceLookupAddress;
/**
* Constructor.
*/
public JNDIAppender() {
}
/**
* @return the sql
*/
public final String getSql() {
return sql;
}
/**
* @param sql the sql to set
*/
public final void setSql(final String sql) {
this.sql = sql;
}
/**
* @return the dataSourceLookupAddress
*/
public final String getDataSourceLookupAddress() {
return dataSourceLookupAddress;
}
/**
* @param dataSourceLookupAddress the dataSourceLookupAddress to set
*/
public final void setDataSourceLookupAddress(final String dataSourceLookupAddress) {
this.dataSourceLookupAddress = dataSourceLookupAddress;
}
private synchronized Connection getConnection() {
if (connection == null) {
try {
final Context ctx = new InitialContext();
final DataSource ds = (DataSource) ctx.lookup(getDataSourceLookupAddress());
connection = ds.getConnection();
connection.setAutoCommit(false);
} catch (final NamingException e) {
errorHandler.error("Datasource JNDI lookup failed: " + dataSourceLookupAddress + "!");
errorHandler.error(e.toString());
} catch (final SQLException e) {
errorHandler.error("Sql connection failed to " + dataSourceLookupAddress + "!");
errorHandler.error(e.toString());
}
}
return connection;
}
private synchronized Statement getStatement() {
if (statement == null) {
try {
statement = getConnection().createStatement();
} catch (final SQLException e) {
errorHandler.error(e.toString());
}
}
return statement;
}
@Override
public void activateOptions() {
if (getSql() == null) {
errorHandler.error("param 'sql' is null!");
}
if (getDataSourceLookupAddress() == null) {
errorHandler.error("param 'DataSourceLookupAddress' is null!");
}
}
/*
* (non-Javadoc)
* @see org.apache.log4j.AppenderSkeleton#append(org.apache.log4j.spi.LoggingEvent)
*/
@Override
protected synchronized void append(final LoggingEvent event) {
try {
((PatternLayout) getLayout()).setConversionPattern(getSql());
final String sqlClause = getLayout().format(event);
getStatement().executeUpdate(sqlClause);
getConnection().commit();
} catch (final SQLException e) {
errorHandler.error(e.toString());
} finally {
close();
}
}
/*
* (non-Javadoc)
* @see org.apache.log4j.AppenderSkeleton#close()
*/
public void close() {
try {
if (statement != null) {
statement.close();
statement = null;
}
} catch (final SQLException e) {
errorHandler.error(e.toString());
} finally {
if (connection != null) {
try {
connection.close();
connection = null;
} catch (final SQLException e) {
errorHandler.error(e.toString());
}
}
}
}
/*
* (non-Javadoc)
* @see org.apache.log4j.AppenderSkeleton#requiresLayout()
*/
public boolean requiresLayout() {
return true;
}
/*
* (non-Javadoc)
* @see org.apache.log4j.AppenderSkeleton#finalize()
*/
@Override
public void finalize() {
close();
super.finalize();
}
}
Now, when exception occurs during EJB method invocation nothing is logged into database, because transaction is rolled back (however, I have set autoCommit to false and commiting transaction manually in JNDIAppender).
My question is: is there a way to log into database in a separate transaction? (I have tried to add @TransactionAttribute(TransactionAttributeType.REQUIRES_NEW) to JNDIAppender, but this didn't helped). Or is there any other solution to be able to log into a database, even if exception has been thrown? I might use a separate data source for logging into a database, but this seems like overkill.
UPD: well, actually JNDIAppener does commits transaction (and thus logs into DB), I've just missed some rows, when I was testing it:) But the problem is that it also commits everything, which was done in EJB before exception (which must not actually be committed).
I must say, that our persistence layer is also JDBC, so basically EJB works with DB using JDBC. So, as far as I see it in JNDIAppender when connection is created it still uses the same transaction, as in EJB. Can I create a separate transaction with JDBC and manage it, while there is already opened transaction exists?
Solution to that issue was using separate Thread (which starts a new transaction) for logging. Something similar to this, but not like this (I don't have exact code under my fingertips):
Thread t = new Thread() {
@Override
public void run() {
try {
((PatternLayout) getLayout()).setConversionPattern(getSql());
final String sqlClause = getLayout().format(event);
getStatement().executeUpdate(sqlClause);
getConnection().commit();
} catch (final SQLException e) {
errorHandler.error(e.toString());
} finally {
close();
}
}
};
t.run();
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