Github user neykov commented on a diff in the pull request:
https://github.com/apache/incubator-brooklyn/pull/705#discussion_r33141300
--- Diff:
core/src/main/java/brooklyn/enricher/basic/YamlTimeWeightedDeltaEnricher.java
---
@@ -0,0 +1,81 @@
+/*
+ * 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 brooklyn.enricher.basic;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import brooklyn.config.ConfigKey;
+import brooklyn.enricher.basic.AbstractTransformer;
+import brooklyn.entity.basic.ConfigKeys;
+import brooklyn.event.SensorEvent;
+import brooklyn.util.flags.TypeCoercions;
+import brooklyn.util.time.Duration;
+
+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);
+
+ 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) {
+ Number 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.doubleValue() -
lastValue.doubleValue()) / (duration / unitMillis);
+ }
+ }
+
+ lastValue = current;
+ lastTime = eventTime;
--- End diff --
Synchronize reads/writes in pairs?
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at [email protected] or file a JIRA ticket
with INFRA.
---
