Add implementation for gauges. (#1365)

* Add implementation for gauges.

* Remove usage of internal class in implcore tests.

2 files changed, 13 insertions, 1 deletions

diff --git a/impl/src/main/java/io/opencensus/impl/metrics/MetricsComponentImpl.java b/impl/src/main/java/io/opencensus/impl/metrics/MetricsComponentImpl.java
index bd8b6154..53c354f1 100644
--- a/impl/src/main/java/io/opencensus/impl/metrics/MetricsComponentImpl.java
+++ b/impl/src/main/java/io/opencensus/impl/metrics/MetricsComponentImpl.java
@@ -16,8 +16,14 @@
 
 package io.opencensus.impl.metrics;
 
+import io.opencensus.implcore.common.MillisClock;
 import io.opencensus.implcore.metrics.MetricsComponentImplBase;
 import io.opencensus.metrics.MetricsComponent;
 
 /** Implementation of {@link MetricsComponent}. */
-public final class MetricsComponentImpl extends MetricsComponentImplBase {}
+public final class MetricsComponentImpl extends MetricsComponentImplBase {
+
+  public MetricsComponentImpl() {
+    super(MillisClock.getInstance());
+  }
+}
diff --git a/impl/src/test/java/io/opencensus/impl/metrics/MetricsTest.java b/impl/src/test/java/io/opencensus/impl/metrics/MetricsTest.java
index d27fa83d..439933de 100644
--- a/impl/src/test/java/io/opencensus/impl/metrics/MetricsTest.java
+++ b/impl/src/test/java/io/opencensus/impl/metrics/MetricsTest.java
@@ -18,6 +18,7 @@ package io.opencensus.impl.metrics;
 
 import static com.google.common.truth.Truth.assertThat;
 
+import io.opencensus.implcore.metrics.MetricRegistryImpl;
 import io.opencensus.implcore.metrics.export.ExportComponentImpl;
 import io.opencensus.metrics.Metrics;
 import io.opencensus.metrics.MetricsComponent;
@@ -33,4 +34,9 @@ public class MetricsTest {
   public void getExportComponent() {
     assertThat(Metrics.getExportComponent()).isInstanceOf(ExportComponentImpl.class);
   }
+
+  @Test
+  public void getMetricRegistry() {
+    assertThat(Metrics.getMetricRegistry()).isInstanceOf(MetricRegistryImpl.class);
+  }
 }