/**
* Copyright 2013 Netflix, Inc.
*
* 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 com.netflix.servo.publish;
import com.google.common.base.Preconditions;
import com.google.common.base.Throwables;
import com.netflix.servo.Metric;
import com.netflix.servo.annotations.DataSourceType;
import com.netflix.servo.annotations.Monitor;
import com.netflix.servo.annotations.MonitorTags;
import com.netflix.servo.tag.BasicTagList;
import com.netflix.servo.tag.StandardTagKeys;
import com.netflix.servo.tag.Tag;
import com.netflix.servo.tag.TagList;
import com.netflix.servo.tag.Tags;
import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;
/**
* Helper class for metric observers that keeps track of the number of calls
* and number of failures.
*/
public abstract class BaseMetricObserver implements MetricObserver {
@MonitorTags
private final TagList tags;
private final String name;
/** Total number of times update has been called. */
@Monitor(name = "updateCount", type = DataSourceType.COUNTER)
private final AtomicInteger updateCount = new AtomicInteger(0);
/** Number of times update failed with an exception. */
@Monitor(name = "updateFailureCount", type = DataSourceType.COUNTER)
private final AtomicInteger failedUpdateCount = new AtomicInteger(0);
/** Creates a new instance with a given name. */
public BaseMetricObserver(String name) {
final Tag id = Tags.newTag(StandardTagKeys.MONITOR_ID.getKeyName(), name);
this.name = Preconditions.checkNotNull(name);
this.tags = BasicTagList.of(id);
}
/**
* Update method that should be defined by sub-classes. This method will
* get invoked and counts will be maintained in the base observer.
*/
public abstract void updateImpl(List<Metric> metrics);
/** {@inheritDoc} */
public final void update(List<Metric> metrics) {
Preconditions.checkNotNull(metrics);
try {
updateImpl(metrics);
} catch (Throwable t) {
failedUpdateCount.incrementAndGet();
throw Throwables.propagate(t);
} finally {
updateCount.incrementAndGet();
}
}
/** {@inheritDoc} */
public final String getName() {
return name;
}
/**
* Can be used by sub-classes to increment the failed count if they handle
* exception internally.
*/
protected final void incrementFailedCount() {
failedUpdateCount.incrementAndGet();
}
/** Returns the total number of times update has been called. */
public int getUpdateCount() {
return updateCount.get();
}
/** Returns the number of times update failed with an exception. */
public int getFailedUpdateCount() {
return failedUpdateCount.get();
}
}