[disk-buffering] Simplify MetricToDiskExporter creation

disk-buffering/src/main/java/io/opentelemetry/contrib/disk/buffering/MetricToDiskExporter.java

@@ -12,10 +12,10 @@
 import io.opentelemetry.sdk.metrics.InstrumentType;
 import io.opentelemetry.sdk.metrics.data.AggregationTemporality;
 import io.opentelemetry.sdk.metrics.data.MetricData;
+import io.opentelemetry.sdk.metrics.export.AggregationTemporalitySelector;
 import io.opentelemetry.sdk.metrics.export.MetricExporter;
 import java.io.IOException;
 import java.util.Collection;
-import java.util.function.Function;
 
 /**
  * This class implements a {@link MetricExporter} that delegates to an instance of {@code
@@ -24,22 +24,17 @@
 public class MetricToDiskExporter implements MetricExporter {
 
   private final ToDiskExporter<MetricData> delegate;
-  private final Function<InstrumentType, AggregationTemporality> typeToTemporality;
+  private final AggregationTemporalitySelector aggregationTemporalitySelector;
 
   /**
    * Creates a new MetricToDiskExporter that will buffer Metric telemetry on disk storage.
    *
    * @param delegate - The MetricExporter to delegate to if disk writing fails.
    * @param config - The StorageConfiguration that specifies how storage is managed.
-   * @param typeToTemporality - The function that maps an InstrumentType into an
-   *     AggregationTemporality.
    * @return A new MetricToDiskExporter instance.
    * @throws IOException if the delegate ToDiskExporter could not be created.
    */
-  public static MetricToDiskExporter create(
-      MetricExporter delegate,
-      StorageConfiguration config,
-      Function<InstrumentType, AggregationTemporality> typeToTemporality)
+  public static MetricToDiskExporter create(MetricExporter delegate, StorageConfiguration config)
       throws IOException {
     ToDiskExporter<MetricData> toDisk =
         ToDiskExporter.<MetricData>builder()
@@ -48,15 +43,14 @@ public static MetricToDiskExporter create(
             .setSerializer(SignalSerializer.ofMetrics())
             .setExportFunction(delegate::export)
             .build();
-    return new MetricToDiskExporter(toDisk, typeToTemporality);
+    return new MetricToDiskExporter(toDisk, delegate);
   }
 
   // VisibleForTesting
   MetricToDiskExporter(
-      ToDiskExporter<MetricData> delegate,
-      Function<InstrumentType, AggregationTemporality> typeToTemporality) {
+      ToDiskExporter<MetricData> delegate, AggregationTemporalitySelector selector) {
     this.delegate = delegate;
-    this.typeToTemporality = typeToTemporality;
+    this.aggregationTemporalitySelector = selector;
   }
 
   @Override
@@ -81,6 +75,6 @@ public CompletableResultCode shutdown() {
 
   @Override
   public AggregationTemporality getAggregationTemporality(InstrumentType instrumentType) {
-    return typeToTemporality.apply(instrumentType);
+    return aggregationTemporalitySelector.getAggregationTemporality(instrumentType);
   }
 }

disk-buffering/src/test/java/io/opentelemetry/contrib/disk/buffering/IntegrationTest.java

@@ -85,9 +85,7 @@ void setUp() throws IOException {
     memoryMetricExporter = InMemoryMetricExporter.create();
     ToDiskExporter<MetricData> toDiskMetricExporter =
         buildToDiskExporter(SignalSerializer.ofMetrics(), memoryMetricExporter::export);
-    metricToDiskExporter =
-        new MetricToDiskExporter(
-            toDiskMetricExporter, memoryMetricExporter::getAggregationTemporality);
+    metricToDiskExporter = new MetricToDiskExporter(toDiskMetricExporter, memoryMetricExporter);
     meterProvider = createMeterProvider(metricToDiskExporter);
     meter = meterProvider.get("MetricInstrumentationScope");