diff options
Diffstat (limited to 'impl_core/src/main/java/io/opencensus/implcore/metrics/DerivedDoubleGaugeImpl.java')
-rw-r--r-- | impl_core/src/main/java/io/opencensus/implcore/metrics/DerivedDoubleGaugeImpl.java | 155 |
1 files changed, 155 insertions, 0 deletions
diff --git a/impl_core/src/main/java/io/opencensus/implcore/metrics/DerivedDoubleGaugeImpl.java b/impl_core/src/main/java/io/opencensus/implcore/metrics/DerivedDoubleGaugeImpl.java new file mode 100644 index 00000000..b7104c9b --- /dev/null +++ b/impl_core/src/main/java/io/opencensus/implcore/metrics/DerivedDoubleGaugeImpl.java @@ -0,0 +1,155 @@ +/* + * Copyright 2018, 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.implcore.metrics; + +import static com.google.common.base.Preconditions.checkArgument; +import static com.google.common.base.Preconditions.checkNotNull; + +import io.opencensus.common.Clock; +import io.opencensus.common.ToDoubleFunction; +import io.opencensus.implcore.internal.Utils; +import io.opencensus.metrics.DerivedDoubleGauge; +import io.opencensus.metrics.LabelKey; +import io.opencensus.metrics.LabelValue; +import io.opencensus.metrics.export.Metric; +import io.opencensus.metrics.export.MetricDescriptor; +import io.opencensus.metrics.export.MetricDescriptor.Type; +import io.opencensus.metrics.export.Point; +import io.opencensus.metrics.export.TimeSeries; +import io.opencensus.metrics.export.Value; +import java.lang.ref.WeakReference; +import java.util.ArrayList; +import java.util.Collections; +import java.util.LinkedHashMap; +import java.util.List; +import java.util.Map; + +/*>>> +import org.checkerframework.checker.nullness.qual.Nullable; +*/ + +/** Implementation of {@link DerivedDoubleGauge}. */ +public final class DerivedDoubleGaugeImpl extends DerivedDoubleGauge implements Meter { + private final MetricDescriptor metricDescriptor; + private final int labelKeysSize; + + @SuppressWarnings("rawtypes") + private volatile Map<List<LabelValue>, PointWithFunction> registeredPoints = + Collections.<List<LabelValue>, PointWithFunction>emptyMap(); + + DerivedDoubleGaugeImpl(String name, String description, String unit, List<LabelKey> labelKeys) { + labelKeysSize = labelKeys.size(); + this.metricDescriptor = + MetricDescriptor.create(name, description, unit, Type.GAUGE_DOUBLE, labelKeys); + } + + @Override + @SuppressWarnings("rawtypes") + public synchronized <T> void createTimeSeries( + List<LabelValue> labelValues, + /*@Nullable*/ T obj, + ToDoubleFunction</*@Nullable*/ T> function) { + Utils.checkListElementNotNull( + checkNotNull(labelValues, "labelValues"), "labelValue element should not be null."); + checkArgument(labelKeysSize == labelValues.size(), "Incorrect number of labels."); + checkNotNull(function, "function"); + + List<LabelValue> labelValuesCopy = + Collections.<LabelValue>unmodifiableList(new ArrayList<LabelValue>(labelValues)); + + PointWithFunction existingPoint = registeredPoints.get(labelValuesCopy); + if (existingPoint != null) { + throw new IllegalArgumentException( + "A different time series with the same labels already exists."); + } + + PointWithFunction newPoint = new PointWithFunction<T>(labelValuesCopy, obj, function); + // Updating the map of time series happens under a lock to avoid multiple add operations + // to happen in the same time. + Map<List<LabelValue>, PointWithFunction> registeredPointsCopy = + new LinkedHashMap<List<LabelValue>, PointWithFunction>(registeredPoints); + registeredPointsCopy.put(labelValuesCopy, newPoint); + registeredPoints = Collections.unmodifiableMap(registeredPointsCopy); + } + + @Override + @SuppressWarnings("rawtypes") + public synchronized void removeTimeSeries(List<LabelValue> labelValues) { + checkNotNull(labelValues, "labelValues"); + + Map<List<LabelValue>, PointWithFunction> registeredPointsCopy = + new LinkedHashMap<List<LabelValue>, PointWithFunction>(registeredPoints); + if (registeredPointsCopy.remove(labelValues) == null) { + // The element not present, no need to update the current map of time series. + return; + } + registeredPoints = Collections.unmodifiableMap(registeredPointsCopy); + } + + @Override + @SuppressWarnings("rawtypes") + public synchronized void clear() { + registeredPoints = Collections.<List<LabelValue>, PointWithFunction>emptyMap(); + } + + /*@Nullable*/ + @Override + @SuppressWarnings("rawtypes") + public Metric getMetric(Clock clock) { + Map<List<LabelValue>, PointWithFunction> currentRegisteredPoints = registeredPoints; + if (currentRegisteredPoints.isEmpty()) { + return null; + } + + if (currentRegisteredPoints.size() == 1) { + PointWithFunction point = currentRegisteredPoints.values().iterator().next(); + return Metric.createWithOneTimeSeries(metricDescriptor, point.getTimeSeries(clock)); + } + + List<TimeSeries> timeSeriesList = new ArrayList<TimeSeries>(currentRegisteredPoints.size()); + for (Map.Entry<List<LabelValue>, PointWithFunction> entry : + currentRegisteredPoints.entrySet()) { + timeSeriesList.add(entry.getValue().getTimeSeries(clock)); + } + return Metric.create(metricDescriptor, timeSeriesList); + } + + /** Implementation of {@link PointWithFunction} with an object and a callback function. */ + public static final class PointWithFunction<T> { + private final List<LabelValue> labelValues; + @javax.annotation.Nullable private final WeakReference<T> ref; + private final ToDoubleFunction</*@Nullable*/ T> function; + + PointWithFunction( + List<LabelValue> labelValues, + /*@Nullable*/ T obj, + ToDoubleFunction</*@Nullable*/ T> function) { + this.labelValues = labelValues; + ref = obj != null ? new WeakReference<T>(obj) : null; + this.function = function; + } + + private TimeSeries getTimeSeries(Clock clock) { + final T obj = ref != null ? ref.get() : null; + double value = function.applyAsDouble(obj); + + // TODO(mayurkale): OPTIMIZATION: Avoid re-evaluate the labelValues all the time (issue#1490). + return TimeSeries.createWithOnePoint( + labelValues, Point.create(Value.doubleValue(value), clock.now()), null); + } + } +} |