/**
* @return Numeric meta data information for the channel or <code>null</code>
* @throws Exception on error
*/
private Display determineDisplay() throws Exception {
// Try numeric meta data
final PreparedStatement statement =
reader
.getRDB()
.getConnection()
.prepareStatement(reader.getSQL().numeric_meta_sel_by_channel);
try {
statement.setInt(1, channel_id);
final ResultSet result = statement.executeQuery();
if (result.next()) {
final NumberFormat format = NumberFormats.format(result.getInt(7)); // prec
return ValueFactory.newDisplay(
result.getDouble(1), // lowerDisplayLimit
result.getDouble(5), // lowerAlarmLimit
result.getDouble(3), // lowerWarningLimit
result.getString(8), // units
format, // numberFormat
result.getDouble(4), // upperWarningLimit
result.getDouble(6), // upperAlarmLimit
result.getDouble(2), // upperDisplayLimit
result.getDouble(1), // lowerCtrlLimit
result.getDouble(2)); // upperCtrlLimit
}
} finally {
statement.close();
}
// No numeric display meta data
return null;
}
/**
* @return Numeric meta data information for the channel or <code>null</code>
* @throws Exception on error
*/
private List<String> determineLabels() throws Exception {
// Try enumerated meta data
List<String> labels = null;
final PreparedStatement statement =
reader
.getRDB()
.getConnection()
.prepareStatement(reader.getSQL().enum_sel_num_val_by_channel);
try {
statement.setInt(1, channel_id);
final ResultSet result = statement.executeQuery();
if (result.next()) {
labels = new ArrayList<String>();
do {
final int id = result.getInt(1);
final String val = result.getString(2);
// Expect vals for ids 0, 1, 2, ...
if (id != labels.size())
throw new Exception(
"Enum IDs for channel with ID " + channel_id + " not in sequential order");
labels.add(val);
} while (result.next());
}
} finally {
statement.close();
}
// Anything found?
if (labels == null || labels.size() <= 0) return null; // Nothing found
return labels;
}
/**
* Given the time and first element of the sample, see if there are more array elements.
*
* @param stamp Time stamp of the sample
* @param dbl0 Value of the first (maybe only) array element
* @param severity Severity of the sample
* @return Array with given element and maybe more.
* @throws Exception on error, including 'cancel'
*/
private double[] readArrayElements(
final Timestamp stamp, final double dbl0, final AlarmSeverity severity) throws Exception {
// For performance reasons, only look for array data until we hit a scalar sample.
if (is_an_array == false) return new double[] {dbl0};
// See if there are more array elements
if (sel_array_samples == null) { // Lazy initialization
sel_array_samples =
reader.getRDB().getConnection().prepareStatement(reader.getSQL().sample_sel_array_vals);
}
sel_array_samples.setInt(1, channel_id);
sel_array_samples.setTimestamp(2, TimestampHelper.toSQLTimestamp(stamp));
// MySQL keeps nanoseconds in designated column, not TIMESTAMP
if (!reader.isOracle()) sel_array_samples.setInt(3, stamp.getNanoSec());
// Assemble array of unknown size in ArrayList ....
final ArrayList<Double> vals = new ArrayList<Double>();
reader.addForCancellation(sel_array_samples);
try {
final ResultSet res = sel_array_samples.executeQuery();
vals.add(new Double(dbl0));
while (res.next()) vals.add(res.getDouble(1));
res.close();
} finally {
reader.removeFromCancellation(sel_array_samples);
}
// Convert to plain double array
final int N = vals.size();
final double ret[] = new double[N];
for (int i = 0; i < N; i++) ret[i] = vals.get(i).doubleValue();
// Check if it's in fact just a scalar, and a valid one
if (N == 1 && severity != AlarmSeverity.UNDEFINED) { // Found a perfect non-array sample:
// Assume that the data is scalar, skip the array check from now on
is_an_array = false;
}
return ret;
}
