diff --git a/java/google/registry/monitoring/metrics/contrib/AbstractMetricSubject.java b/java/google/registry/monitoring/metrics/contrib/AbstractMetricSubject.java
index e6a893e40..562c0bdae 100644
--- a/java/google/registry/monitoring/metrics/contrib/AbstractMetricSubject.java
+++ b/java/google/registry/monitoring/metrics/contrib/AbstractMetricSubject.java
@@ -21,7 +21,7 @@ import com.google.common.base.Joiner;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Lists;
 import com.google.common.collect.Ordering;
-import com.google.common.truth.FailureStrategy;
+import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.Subject;
 import google.registry.monitoring.metrics.Metric;
 import google.registry.monitoring.metrics.MetricPoint;
@@ -34,12 +34,11 @@ import javax.annotation.Nullable;
  *
  * <p>For use with the Google <a href="https://google.github.io/truth/">Truth</a> framework.
  */
-abstract class AbstractMetricSubject<
-        T, M extends Metric<T>, S extends AbstractMetricSubject<T, M, S>>
-    extends Subject<S, M> {
+abstract class AbstractMetricSubject<T, S extends AbstractMetricSubject<T, S>>
+    extends Subject<S, Metric<T>> {
 
   /** And chainer to allow fluent assertions. */
-  public static class And<S extends AbstractMetricSubject<?, ?, S>> {
+  public static class And<S extends AbstractMetricSubject<?, S>> {
 
     private final S subject;
 
@@ -57,7 +56,8 @@ abstract class AbstractMetricSubject<
     return new And<>((S) this);
   }
 
-  /** List of label value tuples about which an assertion has been made so far.
+  /**
+   * List of label value tuples about which an assertion has been made so far.
    *
    * <p>Used to track what tuples have been seen, in order to support hasNoOtherValues() assertions.
    */
@@ -77,8 +77,8 @@ abstract class AbstractMetricSubject<
         }
       };
 
-  protected AbstractMetricSubject(FailureStrategy strategy, M actual) {
-    super(strategy, checkNotNull(actual));
+  protected AbstractMetricSubject(FailureMetadata metadata, Metric<T> actual) {
+    super(metadata, checkNotNull(actual));
   }
 
   /**
@@ -148,9 +148,7 @@ abstract class AbstractMetricSubject<
     return andChainer();
   }
 
-  /**
-   * Asserts that the metric does not have a (non-default) value for the specified label values.
-   */
+  /** Asserts that the metric does not have a (non-default) value for the specified label values. */
   protected And<S> doesNotHaveAnyValueForLabels(String... labels) {
     MetricPoint<T> metricPoint = findMetricPointForLabels(ImmutableList.copyOf(labels));
     if (metricPoint != null) {
@@ -197,6 +195,15 @@ abstract class AbstractMetricSubject<
     return null;
   }
 
+  /**
+   * Returns a string representation of a metric point value, for use in error messages.
+   *
+   * <p>Subclass can override this method if the string needs extra processing.
+   */
+  protected String getMessageRepresentation(T value) {
+    return String.valueOf(value);
+  }
+
   /**
    * Returns true if the metric point has a non-default value.
    *
@@ -204,7 +211,4 @@ abstract class AbstractMetricSubject<
    * return true if the value is not zero, and so on.
    */
   protected abstract boolean hasDefaultValue(MetricPoint<T> metricPoint);
-
-  /** Returns a string representation of a metric point value, for use in error messages. */
-  protected abstract String getMessageRepresentation(T value);
 }
diff --git a/java/google/registry/monitoring/metrics/contrib/EventMetricSubject.java b/java/google/registry/monitoring/metrics/contrib/DistributionMetricSubject.java
similarity index 71%
rename from java/google/registry/monitoring/metrics/contrib/EventMetricSubject.java
rename to java/google/registry/monitoring/metrics/contrib/DistributionMetricSubject.java
index 937ac09e6..69c86bfb1 100644
--- a/java/google/registry/monitoring/metrics/contrib/EventMetricSubject.java
+++ b/java/google/registry/monitoring/metrics/contrib/DistributionMetricSubject.java
@@ -18,24 +18,24 @@ import static com.google.common.truth.Truth.assertAbout;
 
 import com.google.common.collect.BoundType;
 import com.google.common.collect.Range;
-import com.google.common.truth.FailureStrategy;
-import com.google.common.truth.SubjectFactory;
+import com.google.common.truth.FailureMetadata;
+import com.google.common.truth.Subject;
 import google.registry.monitoring.metrics.Distribution;
-import google.registry.monitoring.metrics.EventMetric;
+import google.registry.monitoring.metrics.Metric;
 import google.registry.monitoring.metrics.MetricPoint;
 import java.util.Map;
 import javax.annotation.Nullable;
 
 /**
- * Truth subject for the {@link EventMetric} class.
+ * Truth subject for the {@link Metric<Distribution>} class.
  *
  * <p>For use with the Google <a href="https://google.github.io/truth/">Truth</a> framework. Usage:
  *
- * <pre>  assertThat(myEventMetric)
+ * <pre>  assertThat(myDistributionMetric)
  *       .hasAnyValueForLabels("label1", "label2", "label3")
  *       .and()
  *       .hasNoOtherValues();
- *   assertThat(myEventMetric)
+ *   assertThat(myDistributionMetric)
  *       .doesNotHaveAnyValueForLabels("label1", "label2");
  * </pre>
  *
@@ -44,28 +44,23 @@ import javax.annotation.Nullable;
  * it's difficult to write assertions about expected metric data when any number of empty
  * distributions can also be present, so they are screened out for convenience.
  */
-public final class EventMetricSubject
-    extends AbstractMetricSubject<Distribution, EventMetric, EventMetricSubject> {
+public final class DistributionMetricSubject
+    extends AbstractMetricSubject<Distribution, DistributionMetricSubject> {
 
-  /** {@link SubjectFactory} for assertions about {@link EventMetric} objects. */
-  private static final SubjectFactory<EventMetricSubject, EventMetric>
+  /** {@link Subject.Factory} for assertions about {@link Metric<Distribution>} objects. */
+  private static final Subject.Factory<DistributionMetricSubject, Metric<Distribution>>
       SUBJECT_FACTORY =
-          new SubjectFactory<EventMetricSubject, EventMetric>() {
-            // The Truth extensibility documentation indicates that the target should be nullable.
-            @Override
-            public EventMetricSubject getSubject(
-                FailureStrategy failureStrategy, @Nullable EventMetric target) {
-              return new EventMetricSubject(failureStrategy, target);
-            }
-          };
+          // The Truth extensibility documentation indicates that the target should be nullable.
+          (FailureMetadata failureMetadata, @Nullable Metric<Distribution> target) ->
+              new DistributionMetricSubject(failureMetadata, target);
 
-  /** Static assertThat({@link EventMetric}) shortcut method. */
-  public static EventMetricSubject assertThat(@Nullable EventMetric metric) {
+  /** Static assertThat({@link Metric<Distribution>}) shortcut method. */
+  public static DistributionMetricSubject assertThat(@Nullable Metric<Distribution> metric) {
     return assertAbout(SUBJECT_FACTORY).that(metric);
   }
 
-  private EventMetricSubject(FailureStrategy strategy, EventMetric actual) {
-    super(strategy, actual);
+  private DistributionMetricSubject(FailureMetadata metadata, Metric<Distribution> actual) {
+    super(metadata, actual);
   }
 
   /**
diff --git a/java/google/registry/monitoring/metrics/contrib/IncrementableMetricSubject.java b/java/google/registry/monitoring/metrics/contrib/LongMetricSubject.java
similarity index 56%
rename from java/google/registry/monitoring/metrics/contrib/IncrementableMetricSubject.java
rename to java/google/registry/monitoring/metrics/contrib/LongMetricSubject.java
index aed68d27d..148ffad13 100644
--- a/java/google/registry/monitoring/metrics/contrib/IncrementableMetricSubject.java
+++ b/java/google/registry/monitoring/metrics/contrib/LongMetricSubject.java
@@ -16,24 +16,24 @@ package google.registry.monitoring.metrics.contrib;
 
 import static com.google.common.truth.Truth.assertAbout;
 
-import com.google.common.truth.FailureStrategy;
-import com.google.common.truth.SubjectFactory;
-import google.registry.monitoring.metrics.IncrementableMetric;
+import com.google.common.truth.FailureMetadata;
+import com.google.common.truth.Subject;
+import google.registry.monitoring.metrics.Metric;
 import google.registry.monitoring.metrics.MetricPoint;
 import javax.annotation.Nullable;
 
 /**
- * Truth subject for the {@link IncrementableMetric} class.
+ * Truth subject for the {@link Metric<Long>} class.
  *
  * <p>For use with the Google <a href="https://google.github.io/truth/">Truth</a> framework. Usage:
  *
- * <pre>  assertThat(myIncrementableMetric)
+ * <pre>  assertThat(myLongMetric)
  *       .hasValueForLabels(5, "label1", "label2", "label3")
  *       .and()
  *       .hasAnyValueForLabels("label1", "label2", "label4")
  *       .and()
  *       .hasNoOtherValues();
- *   assertThat(myIncrementableMetric)
+ *   assertThat(myLongMetric)
  *       .doesNotHaveAnyValueForLabels("label1", "label2");
  * </pre>
  *
@@ -42,35 +42,28 @@ import javax.annotation.Nullable;
  * after they are reset. But it's difficult to write assertions about expected metric data when any
  * number of zero values can also be present, so they are screened out for convenience.
  */
-public final class IncrementableMetricSubject
-    extends AbstractMetricSubject<Long, IncrementableMetric, IncrementableMetricSubject> {
+public final class LongMetricSubject extends AbstractMetricSubject<Long, LongMetricSubject> {
 
-  /** {@link SubjectFactory} for assertions about {@link IncrementableMetric} objects. */
-  private static final SubjectFactory<IncrementableMetricSubject, IncrementableMetric>
-      SUBJECT_FACTORY =
-          new SubjectFactory<IncrementableMetricSubject, IncrementableMetric>() {
-            // The Truth extensibility documentation indicates that the target should be nullable.
-            @Override
-            public IncrementableMetricSubject getSubject(
-                FailureStrategy failureStrategy, @Nullable IncrementableMetric target) {
-              return new IncrementableMetricSubject(failureStrategy, target);
-            }
-          };
+  /** {@link Subject.Factory} for assertions about {@link Metric<Long>} objects. */
+  private static final Subject.Factory<LongMetricSubject, Metric<Long>> SUBJECT_FACTORY =
+      // The Truth extensibility documentation indicates that the target should be nullable.
+      (FailureMetadata failureMetadata, @Nullable Metric<Long> target) ->
+          new LongMetricSubject(failureMetadata, target);
 
-  /** Static assertThat({@link IncrementableMetric}) shortcut method. */
-  public static IncrementableMetricSubject assertThat(@Nullable IncrementableMetric metric) {
+  /** Static assertThat({@link Metric<Long>}) shortcut method. */
+  public static LongMetricSubject assertThat(@Nullable Metric<Long> metric) {
     return assertAbout(SUBJECT_FACTORY).that(metric);
   }
 
-  private IncrementableMetricSubject(FailureStrategy strategy, IncrementableMetric actual) {
-    super(strategy, actual);
+  private LongMetricSubject(FailureMetadata metadata, Metric<Long> actual) {
+    super(metadata, actual);
   }
 
   /**
    * Asserts that the metric has a given value for the specified label values. This is a convenience
    * method that takes a long instead of a Long, for ease of use.
    */
-  public And<IncrementableMetricSubject> hasValueForLabels(long value, String... labels) {
+  public And<LongMetricSubject> hasValueForLabels(long value, String... labels) {
     return hasValueForLabels(Long.valueOf(value), labels);
   }
 
@@ -82,10 +75,4 @@ public final class IncrementableMetricSubject
   protected boolean hasDefaultValue(MetricPoint<Long> metricPoint) {
     return metricPoint.value() == 0L;
   }
-
-  /** Returns an appropriate string representation of a metric value for use in error messages. */
-  @Override
-  protected String getMessageRepresentation(Long value) {
-    return String.valueOf(value);
-  }
 }
diff --git a/javatests/google/registry/model/registry/label/PremiumListUtilsTest.java b/javatests/google/registry/model/registry/label/PremiumListUtilsTest.java
index da5a39749..8762f256d 100644
--- a/javatests/google/registry/model/registry/label/PremiumListUtilsTest.java
+++ b/javatests/google/registry/model/registry/label/PremiumListUtilsTest.java
@@ -27,8 +27,8 @@ import static google.registry.model.registry.label.PremiumListUtils.deletePremiu
 import static google.registry.model.registry.label.PremiumListUtils.doesPremiumListExist;
 import static google.registry.model.registry.label.PremiumListUtils.getPremiumPrice;
 import static google.registry.model.registry.label.PremiumListUtils.savePremiumListAndEntries;
-import static google.registry.monitoring.metrics.contrib.EventMetricSubject.assertThat;
-import static google.registry.monitoring.metrics.contrib.IncrementableMetricSubject.assertThat;
+import static google.registry.monitoring.metrics.contrib.DistributionMetricSubject.assertThat;
+import static google.registry.monitoring.metrics.contrib.LongMetricSubject.assertThat;
 import static google.registry.testing.DatastoreHelper.createTld;
 import static google.registry.testing.DatastoreHelper.loadPremiumListEntries;
 import static google.registry.testing.DatastoreHelper.persistPremiumList;
diff --git a/javatests/google/registry/model/registry/label/ReservedListTest.java b/javatests/google/registry/model/registry/label/ReservedListTest.java
index c32eb9255..493cc2be4 100644
--- a/javatests/google/registry/model/registry/label/ReservedListTest.java
+++ b/javatests/google/registry/model/registry/label/ReservedListTest.java
@@ -28,8 +28,8 @@ import static google.registry.model.registry.label.ReservationType.RESERVED_FOR_
 import static google.registry.model.registry.label.ReservedList.getAllowedNameservers;
 import static google.registry.model.registry.label.ReservedList.getReservationTypes;
 import static google.registry.model.registry.label.ReservedList.matchesAnchorTenantReservation;
-import static google.registry.monitoring.metrics.contrib.EventMetricSubject.assertThat;
-import static google.registry.monitoring.metrics.contrib.IncrementableMetricSubject.assertThat;
+import static google.registry.monitoring.metrics.contrib.DistributionMetricSubject.assertThat;
+import static google.registry.monitoring.metrics.contrib.LongMetricSubject.assertThat;
 import static google.registry.testing.DatastoreHelper.createTld;
 import static google.registry.testing.DatastoreHelper.persistReservedList;
 import static google.registry.testing.DatastoreHelper.persistResource;
diff --git a/javatests/google/registry/monitoring/metrics/contrib/EventMetricSubjectTest.java b/javatests/google/registry/monitoring/metrics/contrib/DistributionMetricSubjectTest.java
similarity index 96%
rename from javatests/google/registry/monitoring/metrics/contrib/EventMetricSubjectTest.java
rename to javatests/google/registry/monitoring/metrics/contrib/DistributionMetricSubjectTest.java
index 4460c5b61..15be8d8e9 100644
--- a/javatests/google/registry/monitoring/metrics/contrib/EventMetricSubjectTest.java
+++ b/javatests/google/registry/monitoring/metrics/contrib/DistributionMetricSubjectTest.java
@@ -15,7 +15,7 @@
 package google.registry.monitoring.metrics.contrib;
 
 import static com.google.common.truth.Truth.assertThat;
-import static google.registry.monitoring.metrics.contrib.EventMetricSubject.assertThat;
+import static google.registry.monitoring.metrics.contrib.DistributionMetricSubject.assertThat;
 import static org.junit.Assert.fail;
 
 import com.google.common.collect.ImmutableSet;
@@ -28,7 +28,7 @@ import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
 
 @RunWith(JUnit4.class)
-public class EventMetricSubjectTest {
+public class DistributionMetricSubjectTest {
 
   private static final ImmutableSet<LabelDescriptor> LABEL_DESCRIPTORS =
       ImmutableSet.of(
diff --git a/javatests/google/registry/monitoring/metrics/contrib/IncrementableMetricSubjectTest.java b/javatests/google/registry/monitoring/metrics/contrib/LongMetricSubjectTest.java
similarity index 96%
rename from javatests/google/registry/monitoring/metrics/contrib/IncrementableMetricSubjectTest.java
rename to javatests/google/registry/monitoring/metrics/contrib/LongMetricSubjectTest.java
index 1098575a1..daaece1e0 100644
--- a/javatests/google/registry/monitoring/metrics/contrib/IncrementableMetricSubjectTest.java
+++ b/javatests/google/registry/monitoring/metrics/contrib/LongMetricSubjectTest.java
@@ -15,7 +15,7 @@
 package google.registry.monitoring.metrics.contrib;
 
 import static com.google.common.truth.Truth.assertThat;
-import static google.registry.monitoring.metrics.contrib.IncrementableMetricSubject.assertThat;
+import static google.registry.monitoring.metrics.contrib.LongMetricSubject.assertThat;
 import static org.junit.Assert.fail;
 
 import com.google.common.collect.ImmutableSet;
@@ -28,7 +28,7 @@ import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
 
 @RunWith(JUnit4.class)
-public class IncrementableMetricSubjectTest {
+public class LongMetricSubjectTest {
 
   private static final ImmutableSet<LabelDescriptor> LABEL_DESCRIPTORS =
       ImmutableSet.of(