provide an API method to return an empty LabelSet (#716)

* provide an API method for an empty LabelSet * remove the TestLabelSet now that we have a way to create an empty one
open-telemetry · Dec 18, 2019 · a8d14d8 · a8d14d8
1 parent 95da446
commit a8d14d8
Show file tree

Hide file tree

Showing 11 changed files with 32 additions and 35 deletions.
diff --git a/api/src/main/java/io/opentelemetry/metrics/DefaultMeter.java b/api/src/main/java/io/opentelemetry/metrics/DefaultMeter.java
@@ -164,6 +164,11 @@ public LabelSet createLabelSet(
     return NoopLabelSet.INSTANCE;
   }
 
+  @Override
+  public LabelSet emptyLabelSet() {
+    return NoopLabelSet.INSTANCE;
+  }
+
   /** No-op implementation of LongGauge interface. */
   @Immutable
   private static final class NoopLongGauge implements LongGauge {

diff --git a/api/src/main/java/io/opentelemetry/metrics/Meter.java b/api/src/main/java/io/opentelemetry/metrics/Meter.java
@@ -278,4 +278,12 @@ public interface Meter {
    */
   LabelSet createLabelSet(
       String k1, String v1, String k2, String v2, String k3, String v3, String k4, String v4);
+
+  /**
+   * Returns an empty {@link LabelSet}. The implementation is permitted to have this be a singleton
+   * instance.
+   *
+   * @return an empty {@link LabelSet}
+   */
+  LabelSet emptyLabelSet();
 }
diff --git a/api/src/test/java/io/opentelemetry/OpenTelemetryTest.java b/api/src/test/java/io/opentelemetry/OpenTelemetryTest.java
@@ -391,6 +391,12 @@ public LabelSet createLabelSet(
       return null;
     }
 
+    @Nullable
+    @Override
+    public LabelSet emptyLabelSet() {
+      return null;
+    }
+
     @Override
     public Meter get(String instrumentationName) {
       return new FirstMeterFactory();

diff --git a/api/src/test/java/io/opentelemetry/metrics/DoubleCounterTest.java b/api/src/test/java/io/opentelemetry/metrics/DoubleCounterTest.java
@@ -130,6 +130,6 @@ public void doesNotThrow() {
             .setLabelKeys(LABEL_KEY)
             .setUnit(UNIT)
             .build();
-    doubleCounter.bind(TestLabelSet.empty()).add(1.0);
+    doubleCounter.bind(meter.emptyLabelSet()).add(1.0);
   }
 }
diff --git a/api/src/test/java/io/opentelemetry/metrics/DoubleGaugeTest.java b/api/src/test/java/io/opentelemetry/metrics/DoubleGaugeTest.java
@@ -129,6 +129,6 @@ public void doesNotThrow() {
             .setLabelKeys(LABEL_KEY)
             .setUnit(UNIT)
             .build();
-    doubleGauge.bind(TestLabelSet.empty()).set(5.0);
+    doubleGauge.bind(meter.emptyLabelSet()).set(5.0);
   }
 }
diff --git a/api/src/test/java/io/opentelemetry/metrics/DoubleMeasureTest.java b/api/src/test/java/io/opentelemetry/metrics/DoubleMeasureTest.java
@@ -90,12 +90,12 @@ public void preventNegativeValue() {
     DoubleMeasure myMeasure = meter.doubleMeasureBuilder("MyMeasure").build();
     thrown.expect(IllegalArgumentException.class);
     thrown.expectMessage("Unsupported negative values");
-    myMeasure.bind(TestLabelSet.empty()).record(-5.0);
+    myMeasure.bind(meter.emptyLabelSet()).record(-5.0);
   }
 
   @Test
   public void doesNotThrow() {
     DoubleMeasure myMeasure = meter.doubleMeasureBuilder("MyMeasure").build();
-    myMeasure.bind(TestLabelSet.empty()).record(5.0);
+    myMeasure.bind(meter.emptyLabelSet()).record(5.0);
   }
 }
diff --git a/api/src/test/java/io/opentelemetry/metrics/LongCounterTest.java b/api/src/test/java/io/opentelemetry/metrics/LongCounterTest.java
@@ -129,6 +129,6 @@ public void doesNotThrow() {
             .setLabelKeys(LABEL_KEY)
             .setUnit(UNIT)
             .build();
-    longCounter.bind(TestLabelSet.empty()).add(1);
+    longCounter.bind(meter.emptyLabelSet()).add(1);
   }
 }
diff --git a/api/src/test/java/io/opentelemetry/metrics/LongGaugeTest.java b/api/src/test/java/io/opentelemetry/metrics/LongGaugeTest.java
@@ -126,6 +126,6 @@ public void doesNotThrow() {
             .setLabelKeys(LABEL_KEY)
             .setUnit(UNIT)
             .build();
-    longGauge.bind(TestLabelSet.empty()).set(5);
+    longGauge.bind(meter.emptyLabelSet()).set(5);
   }
 }
diff --git a/api/src/test/java/io/opentelemetry/metrics/LongMeasureTest.java b/api/src/test/java/io/opentelemetry/metrics/LongMeasureTest.java
@@ -90,12 +90,12 @@ public void preventNegativeValue() {
     LongMeasure myMeasure = meter.longMeasureBuilder("MyMeasure").build();
     thrown.expect(IllegalArgumentException.class);
     thrown.expectMessage("Unsupported negative values");
-    myMeasure.bind(TestLabelSet.empty()).record(-5);
+    myMeasure.bind(meter.emptyLabelSet()).record(-5);
   }
 
   @Test
   public void doesNotThrow() {
     LongMeasure myMeasure = meter.longMeasureBuilder("MyMeasure").build();
-    myMeasure.bind(TestLabelSet.empty()).record(5);
+    myMeasure.bind(meter.emptyLabelSet()).record(5);
   }
 }
diff --git a/api/src/test/java/io/opentelemetry/metrics/TestLabelSet.java b/api/src/test/java/io/opentelemetry/metrics/TestLabelSet.java
diff --git a/sdk/src/main/java/io/opentelemetry/sdk/metrics/MeterSdk.java b/sdk/src/main/java/io/opentelemetry/sdk/metrics/MeterSdk.java
@@ -96,4 +96,9 @@ public LabelSet createLabelSet(
       String k1, String v1, String k2, String v2, String k3, String v3, String k4, String v4) {
     throw new UnsupportedOperationException("to be implemented");
   }
+
+  @Override
+  public LabelSet emptyLabelSet() {
+    throw new UnsupportedOperationException("to be implemented");
+  }
 }