/*
* Copyright 2014, The OpenNMS Group
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License. You may obtain
* a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.opennms.newts.aggregate;
import static com.google.common.base.Preconditions.checkNotNull;
import java.util.Iterator;
import java.util.NoSuchElementException;
import org.opennms.newts.api.Measurement;
import org.opennms.newts.api.Results.Row;
import org.opennms.newts.api.query.ResultDescriptor;
import org.opennms.newts.api.query.Calculation;
import com.google.common.base.Optional;
class Compute implements Iterator<Row<Measurement>>, Iterable<Row<Measurement>> {
private final ResultDescriptor m_resultDescriptor;
private final Iterator<Row<Measurement>> m_input;
Compute(ResultDescriptor resultDescriptor, Iterator<Row<Measurement>> input) {
m_resultDescriptor = checkNotNull(resultDescriptor, "result descriptor argument");
m_input = checkNotNull(input, "input argument");
}
@Override
public boolean hasNext() {
return m_input.hasNext();
}
@Override
public Row<Measurement> next() {
if (!hasNext()) throw new NoSuchElementException();
Row<Measurement> row = m_input.next();
for (Calculation calc : m_resultDescriptor.getCalculations().values()) {
double v = calc.getCalculationFunction().apply(getValues(row, calc.getArgs()));
row.addElement(new Measurement(row.getTimestamp(), row.getResource(), calc.getLabel(), v));
}
return row;
}
private double[] getValues(Row<Measurement> row, String[] names) {
double[] values = new double[names.length];
for (int i = 0; i < names.length; i++) {
String name = names[i];
Optional<Double> d = parseDouble(name);
values[i] = d.isPresent() ? d.get() : checkNotNull(row.getElement(name), "Missing measurement; Upstream iterator is bugged").getValue();
}
return values;
}
Optional<Double> parseDouble(String maybeNum) {
try {
return Optional.of(Double.parseDouble(maybeNum));
} catch (NumberFormatException e) {
return Optional.absent();
}
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
@Override
public Iterator<Row<Measurement>> iterator() {
return this;
}
}