fix: simplify conditional call of withContext()

Author: diegomarquezp

gax-java/gax/src/main/java/com/google/api/gax/rpc/ClientContext.java

@@ -44,6 +44,7 @@
 import com.google.api.gax.tracing.ApiTracerContext;
 import com.google.api.gax.tracing.ApiTracerFactory;
 import com.google.api.gax.tracing.BaseApiTracerFactory;
+import com.google.api.gax.tracing.SpanTracerFactory;
 import com.google.auth.ApiKeyCredentials;
 import com.google.auth.CredentialTypeForMetrics;
 import com.google.auth.Credentials;
@@ -275,12 +276,9 @@ public static ClientContext create(StubSettings settings) throws IOException {
             .setServerAddress(endpointContext.resolvedServerAddress())
             .build();
     ApiTracerFactory apiTracerFactory = settings.getTracerFactory();
-    if (apiTracerFactory != null) {
+    if (apiTracerFactory instanceof SpanTracerFactory) {
       apiTracerFactory = apiTracerFactory.withContext(apiTracerContext);
     }
-    if (apiTracerFactory == null) {
-      apiTracerFactory = BaseApiTracerFactory.getInstance();
-    }
 
     return newBuilder()
         .setBackgroundResources(backgroundResources.build())

gax-java/gax/src/test/java/com/google/api/gax/rpc/ClientContextTest.java

@@ -54,7 +54,7 @@
 import com.google.api.gax.rpc.testing.FakeStubSettings;
 import com.google.api.gax.rpc.testing.FakeTransportChannel;
 import com.google.api.gax.tracing.ApiTracerFactory;
-import com.google.api.gax.tracing.BaseApiTracerFactory;
+import com.google.api.gax.tracing.SpanTracerFactory;
 import com.google.auth.ApiKeyCredentials;
 import com.google.auth.CredentialTypeForMetrics;
 import com.google.auth.Credentials;
@@ -1290,34 +1290,21 @@ void test_nullMtlsEndpointIsNotPassedToTransportChannel() throws IOException {
     ClientContext.create(clientSettings);
   }
 
-  @Test
-  void testCreate_withNullTracerFactory() throws IOException {
-    FakeStubSettings.Builder builder = FakeStubSettings.newBuilder();
-    builder.setTransportChannelProvider(getFakeTransportChannelProvider());
-    builder.setCredentialsProvider(
-        FixedCredentialsProvider.create(Mockito.mock(Credentials.class)));
-
-    FakeStubSettings settings = Mockito.spy(builder.build());
-    Mockito.doReturn(null).when(settings).getTracerFactory();
-
-    ClientContext context = ClientContext.create(settings);
-    assertThat(context.getTracerFactory()).isSameInstanceAs(BaseApiTracerFactory.getInstance());
-  }
-
   @Test
   void testCreate_withTracerFactoryReturningNullWithContext() throws IOException {
     FakeStubSettings.Builder builder = FakeStubSettings.newBuilder();
     builder.setTransportChannelProvider(getFakeTransportChannelProvider());
     builder.setCredentialsProvider(
         FixedCredentialsProvider.create(Mockito.mock(Credentials.class)));
 
-    ApiTracerFactory apiTracerFactory = Mockito.mock(ApiTracerFactory.class);
-    Mockito.doReturn(null).when(apiTracerFactory).withContext(Mockito.any());
+    ApiTracerFactory apiTracerFactory = Mockito.mock(SpanTracerFactory.class);
+    Mockito.doReturn(apiTracerFactory).when(apiTracerFactory).withContext(Mockito.any());
 
     FakeStubSettings settings = Mockito.spy(builder.build());
     Mockito.doReturn(apiTracerFactory).when(settings).getTracerFactory();
 
     ClientContext context = ClientContext.create(settings);
-    assertThat(context.getTracerFactory()).isSameInstanceAs(BaseApiTracerFactory.getInstance());
+    assertThat(context.getTracerFactory()).isSameInstanceAs(apiTracerFactory);
+    verify(apiTracerFactory, times(1)).withContext(Mockito.any());
   }
 }