Hi everyone....
i'm tryng to write a translator from implementing select count(*)
from a Select Query with an Expression built at runtime via
ExpressionFactory.
In cayenne 2.0 i was using something like:
static class CountTranslator extends SelectTranslator {
@Override
public String createSqlString() throws Exception {
String sql = super.createSqlString();
int index = sql.indexOf(" FROM ");
return "SELECT COUNT(*)" + sql.substring(index);
}
}
public int count(SelectQuery query,
DataNode node) {
CountTranslator translator = new CountTranslator();
translator.setQuery(query);
translator.setAdapter(node.getAdapter());
translator.setEntityResolver(DataContext.getThreadDataContext().getEntityResolver());
Connection con = null;
PreparedStatement stmt = null;
try {
con = node.getDataSource().getConnection();
translator.setConnection(con);
stmt = translator.createStatement();
ResultSet rs = stmt.executeQuery();
if (rs.next()) {
return rs.getInt(1);
}
throw new org.apache.cayenne.CayenneRuntimeException("Count query
returned no result");
} catch (Exception e) {
throw new CayenneRuntimeException("Cannot count", e);
} finally {
try {
if (stmt != null) {
stmt.close();
}
if (con != null) {
con.close();
}
} catch (Exception ex) {
throw new CayenneRuntimeException("Cannot close connection",
ex);
}
}
}
the only thing i nedeed was to get the current connection from the
context which i did using something like
DataContext.getThreadDataContext().getParentDataDomain().getDataNodes().iterator().next()
but now in Cayenne 3.1 this method seems to be invalid 'cause i cannot
get ParentDataDomain from ObjectContext.
Besides that this works only if have a datanode set for the domain.
Is there any other or better way to proceed?
Thanks, Marco
