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/*
* Copyright 2019, OpenCensus Authors
*
* 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 io.opencensus.metrics;
import io.opencensus.internal.Utils;
import java.util.List;
import javax.annotation.concurrent.ThreadSafe;
/**
* Long Cumulative metric, to report instantaneous measurement of an int64 value. Cumulative values
* can go up or stay the same, but can never go down. Cumulative values cannot be negative.
*
* Example 1: Create a Cumulative with default labels.
*
*
{@code
* class YourClass {
*
* private static final MetricRegistry metricRegistry = Metrics.getMetricRegistry();
*
* List labelKeys = Arrays.asList(LabelKey.create("Name", "desc"));
*
* LongCumulative cumulative = metricRegistry.addLongCumulative(
* "processed_jobs", "Processed jobs", "1", labelKeys);
*
* // It is recommended to keep a reference of a point for manual operations.
* LongPoint defaultPoint = cumulative.getDefaultTimeSeries();
*
* void doWork() {
* // Your code here.
* defaultPoint.add(10);
* }
*
* }
* }
*
* Example 2: You can also use labels(keys and values) to track different types of metric.
*
*
{@code
* class YourClass {
*
* private static final MetricRegistry metricRegistry = Metrics.getMetricRegistry();
*
* List labelKeys = Arrays.asList(LabelKey.create("Name", "desc"));
* List labelValues = Arrays.asList(LabelValue.create("Inbound"));
*
* LongCumulative cumulative = metricRegistry.addLongCumulative(
* "processed_jobs", "Processed jobs", "1", labelKeys);
*
* // It is recommended to keep a reference of a point for manual operations.
* LongPoint inboundPoint = cumulative.getOrCreateTimeSeries(labelValues);
*
* void doSomeWork() {
* // Your code here.
* inboundPoint.set(15);
* }
*
* }
* }
*
* @since 0.21
*/
@ThreadSafe
public abstract class LongCumulative {
/**
* Creates a {@code TimeSeries} and returns a {@code LongPoint} if the specified {@code
* labelValues} is not already associated with this cumulative, else returns an existing {@code
* LongPoint}.
*
* It is recommended to keep a reference to the LongPoint instead of always calling this method
* for manual operations.
*
* @param labelValues the list of label values. The number of label values must be the same to
* that of the label keys passed to {@link MetricRegistry#addLongCumulative}.
* @return a {@code LongPoint} the value of single cumulative.
* @throws NullPointerException if {@code labelValues} is null OR any element of {@code
* labelValues} is null.
* @throws IllegalArgumentException if number of {@code labelValues}s are not equal to the label
* keys passed to {@link MetricRegistry#addLongCumulative}.
* @since 0.21
*/
public abstract LongPoint getOrCreateTimeSeries(List labelValues);
/**
* Returns a {@code LongPoint} for a cumulative with all labels not set, or default labels.
*
* @return a {@code LongPoint} for a cumulative with all labels not set, or default labels.
* @since 0.21
*/
public abstract LongPoint getDefaultTimeSeries();
/**
* Removes the {@code TimeSeries} from the cumulative metric, if it is present. i.e. references to
* previous {@code LongPoint} objects are invalid (not part of the metric).
*
* @param labelValues the list of label values.
* @throws NullPointerException if {@code labelValues} is null.
* @since 0.21
*/
public abstract void removeTimeSeries(List labelValues);
/**
* Removes all {@code TimeSeries} from the cumulative metric. i.e. references to all previous
* {@code LongPoint} objects are invalid (not part of the metric).
*
* @since 0.21
*/
public abstract void clear();
/**
* Returns the no-op implementation of the {@code LongCumulative}.
*
* @return the no-op implementation of the {@code LongCumulative}.
* @since 0.21
*/
static LongCumulative newNoopLongCumulative(
String name, String description, String unit, List labelKeys) {
return NoopLongCumulative.create(name, description, unit, labelKeys);
}
/**
* The value of a single point in the Cumulative.TimeSeries.
*
* @since 0.21
*/
public abstract static class LongPoint {
/**
* Adds the given value to the current value. The values cannot be negative.
*
* @param delta the value to add
* @since 0.21
*/
public abstract void add(long delta);
}
/** No-op implementations of LongCumulative class. */
private static final class NoopLongCumulative extends LongCumulative {
private final int labelKeysSize;
static NoopLongCumulative create(
String name, String description, String unit, List labelKeys) {
return new NoopLongCumulative(name, description, unit, labelKeys);
}
/** Creates a new {@code NoopLongPoint}. */
NoopLongCumulative(String name, String description, String unit, List labelKeys) {
labelKeysSize = labelKeys.size();
}
@Override
public NoopLongPoint getOrCreateTimeSeries(List labelValues) {
Utils.checkListElementNotNull(Utils.checkNotNull(labelValues, "labelValues"), "labelValue");
Utils.checkArgument(
labelKeysSize == labelValues.size(), "Label Keys and Label Values don't have same size.");
return NoopLongPoint.INSTANCE;
}
@Override
public NoopLongPoint getDefaultTimeSeries() {
return NoopLongPoint.INSTANCE;
}
@Override
public void removeTimeSeries(List labelValues) {
Utils.checkNotNull(labelValues, "labelValues");
}
@Override
public void clear() {}
/** No-op implementations of LongPoint class. */
private static final class NoopLongPoint extends LongPoint {
private static final NoopLongPoint INSTANCE = new NoopLongPoint();
private NoopLongPoint() {}
@Override
public void add(long delta) {}
}
}
}