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Diffstat (limited to 'impl_core/src/main/java/io/opencensus/implcore/metrics/LongGaugeImpl.java')
-rw-r--r-- | impl_core/src/main/java/io/opencensus/implcore/metrics/LongGaugeImpl.java | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/impl_core/src/main/java/io/opencensus/implcore/metrics/LongGaugeImpl.java b/impl_core/src/main/java/io/opencensus/implcore/metrics/LongGaugeImpl.java new file mode 100644 index 00000000..4ad4e354 --- /dev/null +++ b/impl_core/src/main/java/io/opencensus/implcore/metrics/LongGaugeImpl.java @@ -0,0 +1,172 @@ +/* + * 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 com.google.common.annotations.VisibleForTesting; +import io.opencensus.common.Clock; +import io.opencensus.implcore.internal.Utils; +import io.opencensus.metrics.LabelKey; +import io.opencensus.metrics.LabelValue; +import io.opencensus.metrics.LongGauge; +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.util.ArrayList; +import java.util.Collections; +import java.util.HashMap; +import java.util.List; +import java.util.Map; +import java.util.concurrent.atomic.AtomicLong; +import javax.annotation.Nullable; + +/** Implementation of {@link LongGauge}. */ +public final class LongGaugeImpl extends LongGauge implements Meter { + @VisibleForTesting static final LabelValue UNSET_VALUE = LabelValue.create(null); + + private final MetricDescriptor metricDescriptor; + private volatile Map<List<LabelValue>, PointImpl> registeredPoints = Collections.emptyMap(); + private final int labelKeysSize; + private final List<LabelValue> defaultLabelValues; + + LongGaugeImpl(String name, String description, String unit, List<LabelKey> labelKeys) { + labelKeysSize = labelKeys.size(); + this.metricDescriptor = + MetricDescriptor.create(name, description, unit, Type.GAUGE_INT64, labelKeys); + + // initialize defaultLabelValues + defaultLabelValues = new ArrayList<LabelValue>(labelKeysSize); + for (int i = 0; i < labelKeysSize; i++) { + defaultLabelValues.add(UNSET_VALUE); + } + } + + @Override + public LongPoint getOrCreateTimeSeries(List<LabelValue> labelValues) { + // lock free point retrieval, if it is present + PointImpl existingPoint = registeredPoints.get(labelValues); + if (existingPoint != null) { + return existingPoint; + } + + List<LabelValue> labelValuesCopy = + Collections.unmodifiableList( + new ArrayList<LabelValue>( + checkNotNull(labelValues, "labelValues should not be null."))); + return registerTimeSeries(labelValuesCopy); + } + + @Override + public LongPoint getDefaultTimeSeries() { + // lock free default point retrieval, if it is present + PointImpl existingPoint = registeredPoints.get(defaultLabelValues); + if (existingPoint != null) { + return existingPoint; + } + return registerTimeSeries(defaultLabelValues); + } + + @Override + public synchronized void removeTimeSeries(List<LabelValue> labelValues) { + checkNotNull(labelValues, "labelValues should not be null."); + + Map<List<LabelValue>, PointImpl> registeredPointsCopy = + new HashMap<List<LabelValue>, PointImpl>(registeredPoints); + if (registeredPointsCopy.remove(labelValues) == null) { + // The element not present, no need to update the current map of points. + return; + } + registeredPoints = Collections.unmodifiableMap(registeredPointsCopy); + } + + @Override + public synchronized void clear() { + registeredPoints = Collections.emptyMap(); + } + + private synchronized LongPoint registerTimeSeries(List<LabelValue> labelValues) { + PointImpl existingPoint = registeredPoints.get(labelValues); + if (existingPoint != null) { + // Return a Point that are already registered. This can happen if a multiple threads + // concurrently try to register the same {@code TimeSeries}. + return existingPoint; + } + + checkArgument(labelKeysSize == labelValues.size(), "Incorrect number of labels."); + Utils.checkListElementNotNull(labelValues, "labelValues element should not be null."); + + PointImpl newPoint = new PointImpl(labelValues); + // Updating the map of points happens under a lock to avoid multiple add operations + // to happen in the same time. + Map<List<LabelValue>, PointImpl> registeredPointsCopy = + new HashMap<List<LabelValue>, PointImpl>(registeredPoints); + registeredPointsCopy.put(labelValues, newPoint); + registeredPoints = Collections.unmodifiableMap(registeredPointsCopy); + + return newPoint; + } + + @Nullable + @Override + public Metric getMetric(Clock clock) { + Map<List<LabelValue>, PointImpl> currentRegisteredPoints = registeredPoints; + + int pointCount = currentRegisteredPoints.size(); + if (pointCount > 0) { + List<TimeSeries> timeSeriesList = new ArrayList<TimeSeries>(pointCount); + for (Map.Entry<List<LabelValue>, PointImpl> entry : currentRegisteredPoints.entrySet()) { + timeSeriesList.add(entry.getValue().getTimeSeries(clock)); + } + + // TODO(mayurkale): optimize this for 1 timeseries (issue #1491). + return Metric.create(metricDescriptor, timeSeriesList); + } + return null; + } + + /** Implementation of {@link LongGauge.LongPoint}. */ + public static final class PointImpl extends LongPoint { + + // TODO(mayurkale): Consider to use LongAdder here, once we upgrade to Java8. + private final AtomicLong value = new AtomicLong(0); + private final List<LabelValue> labelValues; + + PointImpl(List<LabelValue> labelValues) { + this.labelValues = labelValues; + } + + @Override + public void add(long amt) { + value.addAndGet(amt); + } + + @Override + public void set(long val) { + value.set(val); + } + + private TimeSeries getTimeSeries(Clock clock) { + return TimeSeries.createWithOnePoint( + labelValues, Point.create(Value.longValue(value.get()), clock.now()), null); + } + } +} |