Add Nullable annotation to tag values. (#998)

3 files changed, 10 insertions, 6 deletions

diff --git a/exporters/stats/prometheus/src/main/java/io/opencensus/exporter/stats/prometheus/PrometheusExportUtils.java b/exporters/stats/prometheus/src/main/java/io/opencensus/exporter/stats/prometheus/PrometheusExportUtils.java
index 4bc18826..2e0dd232 100644
--- a/exporters/stats/prometheus/src/main/java/io/opencensus/exporter/stats/prometheus/PrometheusExportUtils.java
+++ b/exporters/stats/prometheus/src/main/java/io/opencensus/exporter/stats/prometheus/PrometheusExportUtils.java
@@ -93,7 +93,8 @@ final class PrometheusExportUtils {
         Collector.sanitizeMetricName(OPENCENSUS_NAMESPACE + '_' + view.getName().asString());
     Type type = getType(view.getAggregation(), view.getWindow());
     List<Sample> samples = Lists.newArrayList();
-    for (Entry<List<TagValue>, AggregationData> entry : viewData.getAggregationMap().entrySet()) {
+    for (Entry<List</*@Nullable*/ TagValue>, AggregationData> entry :
+        viewData.getAggregationMap().entrySet()) {
       samples.addAll(getSamples(name, view.getColumns(), entry.getKey(), entry.getValue()));
     }
     return new MetricFamilySamples(
@@ -127,7 +128,7 @@ final class PrometheusExportUtils {
   static List<Sample> getSamples(
       final String name,
       List<TagKey> tagKeys,
-      List<TagValue> tagValues,
+      List</*@Nullable*/ TagValue> tagValues,
       AggregationData aggregationData) {
     Preconditions.checkArgument(
         tagKeys.size() == tagValues.size(), "Tag keys and tag values have different sizes.");
diff --git a/exporters/stats/signalfx/src/main/java/io/opencensus/exporter/stats/signalfx/SignalFxSessionAdaptor.java b/exporters/stats/signalfx/src/main/java/io/opencensus/exporter/stats/signalfx/SignalFxSessionAdaptor.java
index db154a04..8fc74e9c 100644
--- a/exporters/stats/signalfx/src/main/java/io/opencensus/exporter/stats/signalfx/SignalFxSessionAdaptor.java
+++ b/exporters/stats/signalfx/src/main/java/io/opencensus/exporter/stats/signalfx/SignalFxSessionAdaptor.java
@@ -72,7 +72,8 @@ final class SignalFxSessionAdaptor {
     }
 
     List<DataPoint> datapoints = new ArrayList<>(data.getAggregationMap().size());
-    for (Map.Entry<List<TagValue>, AggregationData> entry : data.getAggregationMap().entrySet()) {
+    for (Map.Entry<List</*@Nullable*/ TagValue>, AggregationData> entry :
+        data.getAggregationMap().entrySet()) {
       datapoints.add(
           DataPoint.newBuilder()
               .setMetric(view.getName().asString())
@@ -101,7 +102,8 @@ final class SignalFxSessionAdaptor {
   }
 
   @VisibleForTesting
-  static Iterable<Dimension> createDimensions(List<TagKey> keys, List<TagValue> values) {
+  static Iterable<Dimension> createDimensions(
+      List<TagKey> keys, List</*@Nullable*/ TagValue> values) {
     Preconditions.checkArgument(
         keys.size() == values.size(), "TagKeys and TagValues don't have the same size.");
     List<Dimension> dimensions = new ArrayList<>(keys.size());
diff --git a/exporters/stats/stackdriver/src/main/java/io/opencensus/exporter/stats/stackdriver/StackdriverExportUtils.java b/exporters/stats/stackdriver/src/main/java/io/opencensus/exporter/stats/stackdriver/StackdriverExportUtils.java
index e3abe988..fbd8d250 100644
--- a/exporters/stats/stackdriver/src/main/java/io/opencensus/exporter/stats/stackdriver/StackdriverExportUtils.java
+++ b/exporters/stats/stackdriver/src/main/java/io/opencensus/exporter/stats/stackdriver/StackdriverExportUtils.java
@@ -191,7 +191,8 @@ final class StackdriverExportUtils {
     shared.setValueType(createValueType(view.getAggregation(), view.getMeasure()));
 
     // Each entry in AggregationMap will be converted into an independent TimeSeries object
-    for (Entry<List<TagValue>, AggregationData> entry : viewData.getAggregationMap().entrySet()) {
+    for (Entry<List</*@Nullable*/ TagValue>, AggregationData> entry :
+        viewData.getAggregationMap().entrySet()) {
       TimeSeries.Builder builder = shared.clone();
       builder.setMetric(createMetric(view, entry.getKey()));
       builder.addPoints(
@@ -204,7 +205,7 @@ final class StackdriverExportUtils {
 
   // Create a Metric using the TagKeys and TagValues.
   @VisibleForTesting
-  static Metric createMetric(View view, List<? extends TagValue> tagValues) {
+  static Metric createMetric(View view, List</*@Nullable*/ TagValue> tagValues) {
     Metric.Builder builder = Metric.newBuilder();
     // TODO(songya): use pre-defined metrics for canonical views
     builder.setType(generateType(view.getName().asString()));