style: replace fully qualified names with imports in o11y logic

Cleaned up instances of fully qualified class references (LibraryMetadata, Strings, Nullable) by introducing proper Java import statements across GoldenSignalsMetricsRecorder and its associated tests.

Author: blakeli0

sdk-platform-java/gax-java/gax/src/main/java/com/google/api/gax/tracing/GoldenSignalsMetricsRecorder.java

@@ -29,9 +29,15 @@
  */
 package com.google.api.gax.tracing;
 
+import com.google.api.gax.rpc.LibraryMetadata;
 import io.opentelemetry.api.OpenTelemetry;
 import io.opentelemetry.api.metrics.DoubleHistogram;
 import io.opentelemetry.api.metrics.Meter;
+import io.opentelemetry.api.metrics.MeterBuilder;
+
+import com.google.common.base.Strings;
+import javax.annotation.Nullable;
+
 import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
@@ -53,21 +59,21 @@ class GoldenSignalsMetricsRecorder {
           900.0, 3600.0);
   final DoubleHistogram clientRequestDurationRecorder;
 
-  @javax.annotation.Nullable
+  @Nullable
   static GoldenSignalsMetricsRecorder create(
-      OpenTelemetry openTelemetry, com.google.api.gax.rpc.LibraryMetadata libraryMetadata) {
-    if (libraryMetadata == null || com.google.common.base.Strings.isNullOrEmpty(libraryMetadata.artifactName())) {
+      OpenTelemetry openTelemetry, LibraryMetadata libraryMetadata) {
+    if (libraryMetadata == null || Strings.isNullOrEmpty(libraryMetadata.artifactName())) {
       return null;
     }
     return new GoldenSignalsMetricsRecorder(openTelemetry, libraryMetadata);
   }
 
   private GoldenSignalsMetricsRecorder(
-      OpenTelemetry openTelemetry, com.google.api.gax.rpc.LibraryMetadata libraryMetadata) {
-    io.opentelemetry.api.metrics.MeterBuilder meterBuilder =
+      OpenTelemetry openTelemetry, LibraryMetadata libraryMetadata) {
+    MeterBuilder meterBuilder =
         openTelemetry.meterBuilder(libraryMetadata.artifactName());
     String libraryVersion = libraryMetadata.version();
-    if (!com.google.common.base.Strings.isNullOrEmpty(libraryVersion)) {
+    if (!Strings.isNullOrEmpty(libraryVersion)) {
       meterBuilder.setInstrumentationVersion(libraryVersion);
     }
     Meter meter = meterBuilder.build();

sdk-platform-java/gax-java/gax/src/test/java/com/google/api/gax/tracing/GoldenSignalsMetricsRecorderTest.java

@@ -34,6 +34,7 @@
 import static com.google.api.gax.tracing.GoldenSignalsMetricsRecorder.CLIENT_REQUEST_DURATION_METRIC_NAME;
 import static com.google.common.truth.Truth.assertThat;
 
+import com.google.api.gax.rpc.LibraryMetadata;
 import com.google.common.collect.ImmutableMap;
 import io.opentelemetry.api.OpenTelemetry;
 import io.opentelemetry.api.common.AttributeKey;
@@ -65,7 +66,7 @@ void setUp() {
     recorder =
         GoldenSignalsMetricsRecorder.create(
             openTelemetry,
-            com.google.api.gax.rpc.LibraryMetadata.newBuilder()
+            LibraryMetadata.newBuilder()
                 .setArtifactName(ARTIFACT_NAME)
                 .setVersion("1.2.3")
                 .build());
@@ -130,17 +131,17 @@ void create_shouldReturnNull_whenLibraryMetadataIsNull() {
 
   @Test
   void create_shouldReturnNull_whenArtifactNameIsNull() {
-    com.google.api.gax.rpc.LibraryMetadata metadata =
-        com.google.api.gax.rpc.LibraryMetadata.newBuilder().setVersion("1.0.0").build();
+    LibraryMetadata metadata =
+        LibraryMetadata.newBuilder().setVersion("1.0.0").build();
     GoldenSignalsMetricsRecorder actual =
         GoldenSignalsMetricsRecorder.create(OpenTelemetry.noop(), metadata);
     assertThat(actual).isNull();
   }
 
   @Test
   void create_shouldReturnNull_whenArtifactNameIsEmpty() {
-    com.google.api.gax.rpc.LibraryMetadata metadata =
-        com.google.api.gax.rpc.LibraryMetadata.newBuilder().setArtifactName("").build();
+    LibraryMetadata metadata =
+        LibraryMetadata.newBuilder().setArtifactName("").build();
     GoldenSignalsMetricsRecorder actual =
         GoldenSignalsMetricsRecorder.create(OpenTelemetry.noop(), metadata);
     assertThat(actual).isNull();

sdk-platform-java/gax-java/gax/src/test/java/com/google/api/gax/tracing/GoldenSignalsMetricsTracerTest.java

@@ -70,7 +70,7 @@ void setUp() {
         new GoldenSignalsMetricsTracer(
             GoldenSignalsMetricsRecorder.create(
                 openTelemetry,
-                com.google.api.gax.rpc.LibraryMetadata.newBuilder()
+                LibraryMetadata.newBuilder()
                     .setArtifactName(ARTIFACT_NAME)
                     .setVersion("1.2.3")
                     .build()),