Add Aggregation.LastValue and AggregationData.LastValueData to support Gauge (#1055)

* Add LastValue and LastValueData

* Support LastValue and LastValueData in impl

* Use Utils instead of Precondition

* Add LastValue and remove Mean from match() method.

* Support LastValue and LastValueData in exporters and zpages.

* Update MutableLastValue, add comments on why Mean is still supported.

6 files changed, 223 insertions, 160 deletions

diff --git a/api/src/main/java/io/opencensus/stats/Aggregation.java b/api/src/main/java/io/opencensus/stats/Aggregation.java
index e8579c33..f5efed9b 100644
--- a/api/src/main/java/io/opencensus/stats/Aggregation.java
+++ b/api/src/main/java/io/opencensus/stats/Aggregation.java
@@ -25,12 +25,13 @@ import javax.annotation.concurrent.Immutable;
  * {@link Aggregation} is the process of combining a certain set of {@code MeasureValue}s for a
  * given {@code Measure} into an {@link AggregationData}.
  *
- * <p>{@link Aggregation} currently supports 3 types of basic aggregation:
+ * <p>{@link Aggregation} currently supports 4 types of basic aggregation:
  *
  * <ul>
  *   <li>Sum
  *   <li>Count
  *   <li>Distribution
+ *   <li>LastValue
  * </ul>
  *
  * <p>When creating a {@link View}, one {@link Aggregation} needs to be specified as how to
@@ -46,27 +47,13 @@ public abstract class Aggregation {
   /**
    * Applies the given match function to the underlying data type.
    *
-   * @since 0.8
-   * @deprecated in favor of {@link #match(Function, Function, Function, Function)}.
-   */
-  @Deprecated
-  public abstract <T> T match(
-      Function<? super Sum, T> p0,
-      Function<? super Count, T> p1,
-      Function<? super Mean, T> p2,
-      Function<? super Distribution, T> p3,
-      Function<? super Aggregation, T> defaultFunction);
-
-  /**
-   * Applies the given match function to the underlying data type.
-   *
    * @since 0.13
    */
-  @SuppressWarnings("InconsistentOverloads")
   public abstract <T> T match(
       Function<? super Sum, T> p0,
       Function<? super Count, T> p1,
       Function<? super Distribution, T> p2,
+      Function<? super LastValue, T> p3,
       Function<? super Aggregation, T> defaultFunction);
 
   /**
@@ -96,17 +83,8 @@ public abstract class Aggregation {
     public final <T> T match(
         Function<? super Sum, T> p0,
         Function<? super Count, T> p1,
-        Function<? super Mean, T> p2,
-        Function<? super Distribution, T> p3,
-        Function<? super Aggregation, T> defaultFunction) {
-      return p0.apply(this);
-    }
-
-    @Override
-    public final <T> T match(
-        Function<? super Sum, T> p0,
-        Function<? super Count, T> p1,
         Function<? super Distribution, T> p2,
+        Function<? super LastValue, T> p3,
         Function<? super Aggregation, T> defaultFunction) {
       return p0.apply(this);
     }
@@ -139,17 +117,8 @@ public abstract class Aggregation {
     public final <T> T match(
         Function<? super Sum, T> p0,
         Function<? super Count, T> p1,
-        Function<? super Mean, T> p2,
-        Function<? super Distribution, T> p3,
-        Function<? super Aggregation, T> defaultFunction) {
-      return p1.apply(this);
-    }
-
-    @Override
-    public final <T> T match(
-        Function<? super Sum, T> p0,
-        Function<? super Count, T> p1,
         Function<? super Distribution, T> p2,
+        Function<? super LastValue, T> p3,
         Function<? super Aggregation, T> defaultFunction) {
       return p1.apply(this);
     }
@@ -185,17 +154,8 @@ public abstract class Aggregation {
     public final <T> T match(
         Function<? super Sum, T> p0,
         Function<? super Count, T> p1,
-        Function<? super Mean, T> p2,
-        Function<? super Distribution, T> p3,
-        Function<? super Aggregation, T> defaultFunction) {
-      return p2.apply(this);
-    }
-
-    @Override
-    public final <T> T match(
-        Function<? super Sum, T> p0,
-        Function<? super Count, T> p1,
         Function<? super Distribution, T> p2,
+        Function<? super LastValue, T> p3,
         Function<? super Aggregation, T> defaultFunction) {
       return defaultFunction.apply(this);
     }
@@ -236,10 +196,34 @@ public abstract class Aggregation {
     public final <T> T match(
         Function<? super Sum, T> p0,
         Function<? super Count, T> p1,
-        Function<? super Mean, T> p2,
-        Function<? super Distribution, T> p3,
+        Function<? super Distribution, T> p2,
+        Function<? super LastValue, T> p3,
         Function<? super Aggregation, T> defaultFunction) {
-      return p3.apply(this);
+      return p2.apply(this);
+    }
+  }
+
+  /**
+   * Calculate the last value of aggregated {@code MeasureValue}s.
+   *
+   * @since 0.13
+   */
+  @Immutable
+  @AutoValue
+  public abstract static class LastValue extends Aggregation {
+
+    LastValue() {}
+
+    private static final LastValue INSTANCE = new AutoValue_Aggregation_LastValue();
+
+    /**
+     * Construct a {@code LastValue}.
+     *
+     * @return a new {@code LastValue}.
+     * @since 0.13
+     */
+    public static LastValue create() {
+      return INSTANCE;
     }
 
     @Override
@@ -247,8 +231,9 @@ public abstract class Aggregation {
         Function<? super Sum, T> p0,
         Function<? super Count, T> p1,
         Function<? super Distribution, T> p2,
+        Function<? super LastValue, T> p3,
         Function<? super Aggregation, T> defaultFunction) {
-      return p2.apply(this);
+      return p3.apply(this);
     }
   }
 }
diff --git a/api/src/main/java/io/opencensus/stats/AggregationData.java b/api/src/main/java/io/opencensus/stats/AggregationData.java
index 716e97d8..95ac3282 100644
--- a/api/src/main/java/io/opencensus/stats/AggregationData.java
+++ b/api/src/main/java/io/opencensus/stats/AggregationData.java
@@ -28,13 +28,15 @@ import javax.annotation.concurrent.Immutable;
  * {@link AggregationData} is the result of applying a given {@link Aggregation} to a set of {@code
  * MeasureValue}s.
  *
- * <p>{@link AggregationData} currently supports 4 types of basic aggregation values:
+ * <p>{@link AggregationData} currently supports 6 types of basic aggregation values:
  *
  * <ul>
  *   <li>SumDataDouble
  *   <li>SumDataLong
  *   <li>CountData
  *   <li>DistributionData
+ *   <li>LastValueDataDouble
+ *   <li>LastValueDataLong
  * </ul>
  *
  * <p>{@link ViewData} will contain one {@link AggregationData}, corresponding to its {@link
@@ -50,29 +52,15 @@ public abstract class AggregationData {
   /**
    * Applies the given match function to the underlying data type.
    *
-   * @since 0.8
-   * @deprecated in favor of {@link #match(Function, Function, Function, Function, Function)}.
-   */
-  @Deprecated
-  public abstract <T> T match(
-      Function<? super SumDataDouble, T> p0,
-      Function<? super SumDataLong, T> p1,
-      Function<? super CountData, T> p2,
-      Function<? super MeanData, T> p3,
-      Function<? super DistributionData, T> p4,
-      Function<? super AggregationData, T> defaultFunction);
-
-  /**
-   * Applies the given match function to the underlying data type.
-   *
    * @since 0.13
    */
-  @SuppressWarnings("InconsistentOverloads")
   public abstract <T> T match(
       Function<? super SumDataDouble, T> p0,
       Function<? super SumDataLong, T> p1,
       Function<? super CountData, T> p2,
       Function<? super DistributionData, T> p3,
+      Function<? super LastValueDataDouble, T> p4,
+      Function<? super LastValueDataLong, T> p5,
       Function<? super AggregationData, T> defaultFunction);
 
   /**
@@ -110,18 +98,9 @@ public abstract class AggregationData {
         Function<? super SumDataDouble, T> p0,
         Function<? super SumDataLong, T> p1,
         Function<? super CountData, T> p2,
-        Function<? super MeanData, T> p3,
-        Function<? super DistributionData, T> p4,
-        Function<? super AggregationData, T> defaultFunction) {
-      return p0.apply(this);
-    }
-
-    @Override
-    public final <T> T match(
-        Function<? super SumDataDouble, T> p0,
-        Function<? super SumDataLong, T> p1,
-        Function<? super CountData, T> p2,
         Function<? super DistributionData, T> p3,
+        Function<? super LastValueDataDouble, T> p4,
+        Function<? super LastValueDataLong, T> p5,
         Function<? super AggregationData, T> defaultFunction) {
       return p0.apply(this);
     }
@@ -162,18 +141,9 @@ public abstract class AggregationData {
         Function<? super SumDataDouble, T> p0,
         Function<? super SumDataLong, T> p1,
         Function<? super CountData, T> p2,
-        Function<? super MeanData, T> p3,
-        Function<? super DistributionData, T> p4,
-        Function<? super AggregationData, T> defaultFunction) {
-      return p1.apply(this);
-    }
-
-    @Override
-    public final <T> T match(
-        Function<? super SumDataDouble, T> p0,
-        Function<? super SumDataLong, T> p1,
-        Function<? super CountData, T> p2,
         Function<? super DistributionData, T> p3,
+        Function<? super LastValueDataDouble, T> p4,
+        Function<? super LastValueDataLong, T> p5,
         Function<? super AggregationData, T> defaultFunction) {
       return p1.apply(this);
     }
@@ -214,18 +184,9 @@ public abstract class AggregationData {
         Function<? super SumDataDouble, T> p0,
         Function<? super SumDataLong, T> p1,
         Function<? super CountData, T> p2,
-        Function<? super MeanData, T> p3,
-        Function<? super DistributionData, T> p4,
-        Function<? super AggregationData, T> defaultFunction) {
-      return p2.apply(this);
-    }
-
-    @Override
-    public final <T> T match(
-        Function<? super SumDataDouble, T> p0,
-        Function<? super SumDataLong, T> p1,
-        Function<? super CountData, T> p2,
         Function<? super DistributionData, T> p3,
+        Function<? super LastValueDataDouble, T> p4,
+        Function<? super LastValueDataLong, T> p5,
         Function<? super AggregationData, T> defaultFunction) {
       return p2.apply(this);
     }
@@ -278,18 +239,9 @@ public abstract class AggregationData {
         Function<? super SumDataDouble, T> p0,
         Function<? super SumDataLong, T> p1,
         Function<? super CountData, T> p2,
-        Function<? super MeanData, T> p3,
-        Function<? super DistributionData, T> p4,
-        Function<? super AggregationData, T> defaultFunction) {
-      return p3.apply(this);
-    }
-
-    @Override
-    public final <T> T match(
-        Function<? super SumDataDouble, T> p0,
-        Function<? super SumDataLong, T> p1,
-        Function<? super CountData, T> p2,
         Function<? super DistributionData, T> p3,
+        Function<? super LastValueDataDouble, T> p4,
+        Function<? super LastValueDataLong, T> p5,
         Function<? super AggregationData, T> defaultFunction) {
       return defaultFunction.apply(this);
     }
@@ -394,11 +346,86 @@ public abstract class AggregationData {
         Function<? super SumDataDouble, T> p0,
         Function<? super SumDataLong, T> p1,
         Function<? super CountData, T> p2,
-        Function<? super MeanData, T> p3,
-        Function<? super DistributionData, T> p4,
+        Function<? super DistributionData, T> p3,
+        Function<? super LastValueDataDouble, T> p4,
+        Function<? super LastValueDataLong, T> p5,
+        Function<? super AggregationData, T> defaultFunction) {
+      return p3.apply(this);
+    }
+  }
+
+  /**
+   * The last value of aggregated {@code MeasureValueDouble}s.
+   *
+   * @since 0.13
+   */
+  @Immutable
+  @AutoValue
+  public abstract static class LastValueDataDouble extends AggregationData {
+
+    LastValueDataDouble() {}
+
+    /**
+     * Creates a {@code LastValueDataDouble}.
+     *
+     * @param lastValue the last value.
+     * @return a {@code LastValueDataDouble}.
+     * @since 0.13
+     */
+    public static LastValueDataDouble create(double lastValue) {
+      return new AutoValue_AggregationData_LastValueDataDouble(lastValue);
+    }
+
+    /**
+     * Returns the last value.
+     *
+     * @return the last value.
+     * @since 0.13
+     */
+    public abstract double getLastValue();
+
+    @Override
+    public final <T> T match(
+        Function<? super SumDataDouble, T> p0,
+        Function<? super SumDataLong, T> p1,
+        Function<? super CountData, T> p2,
+        Function<? super DistributionData, T> p3,
+        Function<? super LastValueDataDouble, T> p4,
+        Function<? super LastValueDataLong, T> p5,
         Function<? super AggregationData, T> defaultFunction) {
       return p4.apply(this);
     }
+  }
+
+  /**
+   * The last value of aggregated {@code MeasureValueLong}s.
+   *
+   * @since 0.13
+   */
+  @Immutable
+  @AutoValue
+  public abstract static class LastValueDataLong extends AggregationData {
+
+    LastValueDataLong() {}
+
+    /**
+     * Creates a {@code LastValueDataLong}.
+     *
+     * @param lastValue the last value.
+     * @return a {@code LastValueDataLong}.
+     * @since 0.13
+     */
+    public static LastValueDataLong create(long lastValue) {
+      return new AutoValue_AggregationData_LastValueDataLong(lastValue);
+    }
+
+    /**
+     * Returns the last value.
+     *
+     * @return the last value.
+     * @since 0.13
+     */
+    public abstract long getLastValue();
 
     @Override
     public final <T> T match(
@@ -406,8 +433,10 @@ public abstract class AggregationData {
         Function<? super SumDataLong, T> p1,
         Function<? super CountData, T> p2,
         Function<? super DistributionData, T> p3,
+        Function<? super LastValueDataDouble, T> p4,
+        Function<? super LastValueDataLong, T> p5,
         Function<? super AggregationData, T> defaultFunction) {
-      return p3.apply(this);
+      return p5.apply(this);
     }
   }
 }
diff --git a/api/src/main/java/io/opencensus/stats/ViewData.java b/api/src/main/java/io/opencensus/stats/ViewData.java
index c511edab..259f1068 100644
--- a/api/src/main/java/io/opencensus/stats/ViewData.java
+++ b/api/src/main/java/io/opencensus/stats/ViewData.java
@@ -24,9 +24,12 @@ import io.opencensus.common.Timestamp;
 import io.opencensus.internal.Utils;
 import io.opencensus.stats.Aggregation.Count;
 import io.opencensus.stats.Aggregation.Distribution;
+import io.opencensus.stats.Aggregation.LastValue;
 import io.opencensus.stats.Aggregation.Sum;
 import io.opencensus.stats.AggregationData.CountData;
 import io.opencensus.stats.AggregationData.DistributionData;
+import io.opencensus.stats.AggregationData.LastValueDataDouble;
+import io.opencensus.stats.AggregationData.LastValueDataLong;
 import io.opencensus.stats.AggregationData.SumDataDouble;
 import io.opencensus.stats.AggregationData.SumDataLong;
 import io.opencensus.stats.Measure.MeasureDouble;
@@ -272,25 +275,56 @@ public abstract class ViewData {
             return null;
           }
         },
-        new Function<Aggregation.Mean, Void>() {
+        new Function<Distribution, Void>() {
           @Override
-          public Void apply(Aggregation.Mean arg) {
+          public Void apply(Distribution arg) {
             Utils.checkArgument(
-                aggregationData instanceof AggregationData.MeanData,
+                aggregationData instanceof DistributionData,
                 createErrorMessageForAggregation(aggregation, aggregationData));
             return null;
           }
         },
-        new Function<Distribution, Void>() {
+        new Function<LastValue, Void>() {
           @Override
-          public Void apply(Distribution arg) {
-            Utils.checkArgument(
-                aggregationData instanceof DistributionData,
-                createErrorMessageForAggregation(aggregation, aggregationData));
+          public Void apply(LastValue arg) {
+            measure.match(
+                new Function<MeasureDouble, Void>() {
+                  @Override
+                  public Void apply(MeasureDouble arg) {
+                    Utils.checkArgument(
+                        aggregationData instanceof LastValueDataDouble,
+                        createErrorMessageForAggregation(aggregation, aggregationData));
+                    return null;
+                  }
+                },
+                new Function<MeasureLong, Void>() {
+                  @Override
+                  public Void apply(MeasureLong arg) {
+                    Utils.checkArgument(
+                        aggregationData instanceof LastValueDataLong,
+                        createErrorMessageForAggregation(aggregation, aggregationData));
+                    return null;
+                  }
+                },
+                Functions.</*@Nullable*/ Void>throwAssertionError());
             return null;
           }
         },
-        Functions.</*@Nullable*/ Void>throwAssertionError());
+        new Function<Aggregation, Void>() {
+          @Override
+          public Void apply(Aggregation arg) {
+            // TODO(songya): remove this once Mean aggregation is completely removed. Before that
+            // we need to continue supporting Mean, since it could still be used by users and some
+            // deprecated RPC views.
+            if (arg instanceof Aggregation.Mean) {
+              Utils.checkArgument(
+                  aggregationData instanceof AggregationData.MeanData,
+                  createErrorMessageForAggregation(aggregation, aggregationData));
+              return null;
+            }
+            throw new AssertionError();
+          }
+        });
   }
 
   private static String createErrorMessageForAggregation(
diff --git a/api/src/test/java/io/opencensus/stats/AggregationDataTest.java b/api/src/test/java/io/opencensus/stats/AggregationDataTest.java
index 3431d043..9f2aa589 100644
--- a/api/src/test/java/io/opencensus/stats/AggregationDataTest.java
+++ b/api/src/test/java/io/opencensus/stats/AggregationDataTest.java
@@ -23,6 +23,8 @@ import io.opencensus.common.Function;
 import io.opencensus.common.Functions;
 import io.opencensus.stats.AggregationData.CountData;
 import io.opencensus.stats.AggregationData.DistributionData;
+import io.opencensus.stats.AggregationData.LastValueDataDouble;
+import io.opencensus.stats.AggregationData.LastValueDataLong;
 import io.opencensus.stats.AggregationData.MeanData;
 import io.opencensus.stats.AggregationData.SumDataDouble;
 import io.opencensus.stats.AggregationData.SumDataLong;
@@ -95,6 +97,8 @@ public class AggregationDataTest {
         .addEqualityGroup(DistributionData.create(10, 10, 1, 1, 55.5, Arrays.asList(0L, 10L, 0L)))
         .addEqualityGroup(MeanData.create(5.0, 1), MeanData.create(5.0, 1))
         .addEqualityGroup(MeanData.create(-5.0, 1), MeanData.create(-5.0, 1))
+        .addEqualityGroup(LastValueDataDouble.create(20.0), LastValueDataDouble.create(20.0))
+        .addEqualityGroup(LastValueDataLong.create(20), LastValueDataLong.create(20))
         .testEquals();
   }
 
@@ -105,8 +109,9 @@ public class AggregationDataTest {
             SumDataDouble.create(10.0),
             SumDataLong.create(100000000),
             CountData.create(40),
-            MeanData.create(5.0, 1),
-            DistributionData.create(1, 1, 1, 1, 0, Arrays.asList(0L, 10L, 0L)));
+            DistributionData.create(1, 1, 1, 1, 0, Arrays.asList(0L, 10L, 0L)),
+            LastValueDataDouble.create(20.0),
+            LastValueDataLong.create(200000000L));
 
     final List<Object> actual = new ArrayList<Object>();
     for (AggregationData aggregation : aggregations) {
@@ -132,17 +137,24 @@ public class AggregationDataTest {
               return null;
             }
           },
-          new Function<MeanData, Void>() {
+          new Function<DistributionData, Void>() {
             @Override
-            public Void apply(MeanData arg) {
-              actual.add(arg.getMean());
+            public Void apply(DistributionData arg) {
+              actual.add(arg.getBucketCounts());
               return null;
             }
           },
-          new Function<DistributionData, Void>() {
+          new Function<LastValueDataDouble, Void>() {
             @Override
-            public Void apply(DistributionData arg) {
-              actual.add(arg.getBucketCounts());
+            public Void apply(LastValueDataDouble arg) {
+              actual.add(arg.getLastValue());
+              return null;
+            }
+          },
+          new Function<LastValueDataLong, Void>() {
+            @Override
+            public Void apply(LastValueDataLong arg) {
+              actual.add(arg.getLastValue());
               return null;
             }
           },
@@ -150,6 +162,7 @@ public class AggregationDataTest {
     }
 
     assertThat(actual)
-        .isEqualTo(Arrays.asList(10.0, 100000000L, 40L, 5.0, Arrays.asList(0L, 10L, 0L)));
+        .containsExactly(10.0, 100000000L, 40L, Arrays.asList(0L, 10L, 0L), 20.0, 200000000L)
+        .inOrder();
   }
 }
diff --git a/api/src/test/java/io/opencensus/stats/AggregationTest.java b/api/src/test/java/io/opencensus/stats/AggregationTest.java
index 3ef131b8..c2e6a716 100644
--- a/api/src/test/java/io/opencensus/stats/AggregationTest.java
+++ b/api/src/test/java/io/opencensus/stats/AggregationTest.java
@@ -19,10 +19,10 @@ package io.opencensus.stats;
 import static com.google.common.truth.Truth.assertThat;
 
 import com.google.common.testing.EqualsTester;
-import io.opencensus.common.Function;
 import io.opencensus.common.Functions;
 import io.opencensus.stats.Aggregation.Count;
 import io.opencensus.stats.Aggregation.Distribution;
+import io.opencensus.stats.Aggregation.LastValue;
 import io.opencensus.stats.Aggregation.Mean;
 import io.opencensus.stats.Aggregation.Sum;
 import java.util.ArrayList;
@@ -66,6 +66,7 @@ public class AggregationTest {
             Distribution.create(BucketBoundaries.create(Arrays.asList(0.0, 1.0, 5.0))),
             Distribution.create(BucketBoundaries.create(Arrays.asList(0.0, 1.0, 5.0))))
         .addEqualityGroup(Mean.create(), Mean.create())
+        .addEqualityGroup(LastValue.create(), LastValue.create())
         .testEquals();
   }
 
@@ -76,39 +77,21 @@ public class AggregationTest {
             Sum.create(),
             Count.create(),
             Mean.create(),
-            Distribution.create(BucketBoundaries.create(Arrays.asList(-10.0, 1.0, 5.0))));
+            Distribution.create(BucketBoundaries.create(Arrays.asList(-10.0, 1.0, 5.0))),
+            LastValue.create());
 
     List<String> actual = new ArrayList<String>();
     for (Aggregation aggregation : aggregations) {
       actual.add(
           aggregation.match(
-              new Function<Sum, String>() {
-                @Override
-                public String apply(Sum arg) {
-                  return "SUM";
-                }
-              },
-              new Function<Count, String>() {
-                @Override
-                public String apply(Count arg) {
-                  return "COUNT";
-                }
-              },
-              new Function<Mean, String>() {
-                @Override
-                public String apply(Mean arg) {
-                  return "MEAN";
-                }
-              },
-              new Function<Distribution, String>() {
-                @Override
-                public String apply(Distribution arg) {
-                  return "DISTRIBUTION";
-                }
-              },
-              Functions.<String>throwIllegalArgumentException()));
+              Functions.returnConstant("SUM"),
+              Functions.returnConstant("COUNT"),
+              Functions.returnConstant("DISTRIBUTION"),
+              Functions.returnConstant("LASTVALUE"),
+              Functions.returnConstant("UNKNOWN")));
     }
 
-    assertThat(actual).isEqualTo(Arrays.asList("SUM", "COUNT", "MEAN", "DISTRIBUTION"));
+    assertThat(actual)
+        .isEqualTo(Arrays.asList("SUM", "COUNT", "UNKNOWN", "DISTRIBUTION", "LASTVALUE"));
   }
 }
diff --git a/api/src/test/java/io/opencensus/stats/ViewDataTest.java b/api/src/test/java/io/opencensus/stats/ViewDataTest.java
index 0dc78e33..89009f34 100644
--- a/api/src/test/java/io/opencensus/stats/ViewDataTest.java
+++ b/api/src/test/java/io/opencensus/stats/ViewDataTest.java
@@ -27,10 +27,13 @@ import io.opencensus.common.Functions;
 import io.opencensus.common.Timestamp;
 import io.opencensus.stats.Aggregation.Count;
 import io.opencensus.stats.Aggregation.Distribution;
+import io.opencensus.stats.Aggregation.LastValue;
 import io.opencensus.stats.Aggregation.Mean;
 import io.opencensus.stats.Aggregation.Sum;
 import io.opencensus.stats.AggregationData.CountData;
 import io.opencensus.stats.AggregationData.DistributionData;
+import io.opencensus.stats.AggregationData.LastValueDataDouble;
+import io.opencensus.stats.AggregationData.LastValueDataLong;
 import io.opencensus.stats.AggregationData.SumDataDouble;
 import io.opencensus.stats.AggregationData.SumDataLong;
 import io.opencensus.stats.View.AggregationWindow;
@@ -218,6 +221,22 @@ public final class ViewDataTest {
             CountData.create(100)));
   }
 
+  @Test
+  public void preventAggregationAndAggregationDataMismatch_LastValueDouble_LastValueLong() {
+    aggregationAndAggregationDataMismatch(
+        createView(LastValue.create(), MEASURE_DOUBLE),
+        ImmutableMap.<List<TagValue>, AggregationData>of(
+            Arrays.asList(V1, V2), LastValueDataLong.create(100)));
+  }
+
+  @Test
+  public void preventAggregationAndAggregationDataMismatch_LastValueLong_LastValueDouble() {
+    aggregationAndAggregationDataMismatch(
+        createView(LastValue.create(), MEASURE_LONG),
+        ImmutableMap.<List<TagValue>, AggregationData>of(
+            Arrays.asList(V1, V2), LastValueDataDouble.create(100)));
+  }
+
   private static View createView(Aggregation aggregation) {
     return createView(aggregation, MEASURE_DOUBLE);
   }