/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.brooklyn.enricher.stock;
import org.apache.brooklyn.api.sensor.SensorEvent;
import org.apache.brooklyn.config.ConfigKey;
import org.apache.brooklyn.core.config.ConfigKeys;
import org.apache.brooklyn.enricher.stock.AbstractTransformer;
import org.apache.brooklyn.util.core.flags.TypeCoercions;
import org.apache.brooklyn.util.time.Duration;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.google.common.base.Function;
/**
* Converts an absolute count sensor into a delta sensor (i.e. the diff between the current and previous value),
* presented as a units/timeUnit based on the event timing.
* <p>
* For example, given a requests.count sensor, this can make a requests.per_sec sensor with {@link #DELTA_PERIOD} set to "1s" (the default).
* <p>
* Suitable for configuration from YAML.
*/
public class YamlTimeWeightedDeltaEnricher<T extends Number> extends AbstractTransformer<T,Double> {
private static final Logger LOG = LoggerFactory.getLogger(YamlTimeWeightedDeltaEnricher.class);
transient Object lock = new Object();
Number lastValue;
long lastTime = -1;
public static ConfigKey<Duration> DELTA_PERIOD = ConfigKeys.newConfigKey(Duration.class, "enricher.delta.period",
"Duration that this delta should compute for, default per second", Duration.ONE_SECOND);
@Override
protected Function<SensorEvent<T>, Double> getTransformation() {
return new Function<SensorEvent<T>, Double>() {
@Override
public Double apply(SensorEvent<T> event) {
synchronized (lock) {
Double current = TypeCoercions.coerce(event.getValue(), Double.class);
if (current == null) return null;
long eventTime = event.getTimestamp();
long unitMillis = getConfig(DELTA_PERIOD).toMilliseconds();
Double result = null;
if (eventTime > 0 && eventTime > lastTime) {
if (lastValue == null || lastTime < 0) {
// cannot calculate time-based delta with a single value
if (LOG.isTraceEnabled()) LOG.trace("{} received event but no last value so will not emit, null -> {} at {}", new Object[] {this, current, eventTime});
} else {
double duration = eventTime - lastTime;
result = (current - lastValue.doubleValue()) / (duration / unitMillis);
}
}
lastValue = current;
lastTime = eventTime;
return result;
}
}
};
}
}