make extended tracer easier to use

api/incubator/src/main/java/io/opentelemetry/api/incubator/trace/ExtendedDefaultTracer.java

@@ -10,7 +10,6 @@
 import io.opentelemetry.api.incubator.propagation.ExtendedContextPropagators;
 import io.opentelemetry.api.internal.ApiUsageLogger;
 import io.opentelemetry.api.trace.Span;
-import io.opentelemetry.api.trace.SpanBuilder;
 import io.opentelemetry.api.trace.SpanContext;
 import io.opentelemetry.api.trace.SpanKind;
 import io.opentelemetry.api.trace.Tracer;
@@ -33,7 +32,7 @@ static Tracer getNoop() {
   }
 
   @Override
-  public SpanBuilder spanBuilder(String spanName) {
+  public ExtendedSpanBuilder spanBuilder(String spanName) {
     return NoopSpanBuilder.create();
   }
 

api/incubator/src/main/java/io/opentelemetry/api/incubator/trace/ExtendedTracer.java

@@ -20,4 +20,7 @@ public interface ExtendedTracer extends Tracer {
   default boolean isEnabled() {
     return true;
   }
+
+  @Override
+  ExtendedSpanBuilder spanBuilder(String spanName);
 }

api/incubator/src/test/java/io/opentelemetry/api/incubator/trace/ExtendedTraceApiUsageTest.java

@@ -166,27 +166,32 @@ void startAndCallOrRun() {
 
     // Get a Tracer for a scope
     Tracer tracer = tracerProvider.get("org.foo.my-scope");
+    ExtendedTracer extendedTracer = (ExtendedTracer) tracer;
 
     // Wrap the resetCheckout method in a span
     String cartId =
         ((ExtendedSpanBuilder) tracer.spanBuilder("reset_checkout_and_return"))
             .setAttribute("key123", "val456")
             .startAndCall(() -> resetCheckoutAndReturn("abc123", /* throwException= */ false));
     assertThat(cartId).isEqualTo("abc123");
+    // ...or use ExtendedTracer instance
     // ...or runnable variation
-    ((ExtendedSpanBuilder) tracer.spanBuilder("reset_checkout"))
+    extendedTracer
+        .spanBuilder("reset_checkout")
         .startAndRun(() -> resetCheckout("abc123", /* throwException= */ false));
 
     // Wrap the resetCheckout method in a span; resetCheckout throws an exception
     try {
-      ((ExtendedSpanBuilder) tracer.spanBuilder("reset_checkout_and_return"))
+      extendedTracer
+          .spanBuilder("reset_checkout_and_return")
           .startAndCall(() -> resetCheckoutAndReturn("def456", /* throwException= */ true));
     } catch (Throwable e) {
       // Ignore expected exception
     }
     // ...or runnable variation
     try {
-      ((ExtendedSpanBuilder) tracer.spanBuilder("reset_checkout"))
+      extendedTracer
+          .spanBuilder("reset_checkout")
           .startAndRun(() -> resetCheckout("def456", /* throwException= */ true));
     } catch (Throwable e) {
       // Ignore expected exception
@@ -195,7 +200,8 @@ void startAndCallOrRun() {
     // Wrap the resetCheckout method in a span; resetCheckout throws an exception; use custom error
     // handler
     try {
-      ((ExtendedSpanBuilder) tracer.spanBuilder("reset_checkout_and_return"))
+      extendedTracer
+          .spanBuilder("reset_checkout_and_return")
           .startAndCall(
               () -> resetCheckoutAndReturn("ghi789", /* throwException= */ true),
               (span, throwable) -> span.setAttribute("my-attribute", "error"));
@@ -204,7 +210,8 @@ void startAndCallOrRun() {
     }
     // ...or runnable variation
     try {
-      ((ExtendedSpanBuilder) tracer.spanBuilder("reset_checkout"))
+      extendedTracer
+          .spanBuilder("reset_checkout")
           .startAndRun(
               () -> resetCheckout("ghi789", /* throwException= */ true),
               (span, throwable) -> span.setAttribute("my-attribute", "error"));

integration-tests/graal-incubating/src/test/java/io/opentelemetry/integrationtests/graal/IncubatingApiTests.java

@@ -7,7 +7,6 @@
 
 import static org.assertj.core.api.Assertions.assertThat;
 
-import io.opentelemetry.api.incubator.logs.ExtendedLogRecordBuilder;
 import io.opentelemetry.api.incubator.logs.ExtendedLogger;
 import io.opentelemetry.api.incubator.metrics.ExtendedDoubleCounter;
 import io.opentelemetry.api.incubator.metrics.ExtendedDoubleGauge;
@@ -18,7 +17,6 @@
 import io.opentelemetry.api.incubator.metrics.ExtendedLongGauge;
 import io.opentelemetry.api.incubator.metrics.ExtendedLongHistogram;
 import io.opentelemetry.api.incubator.metrics.ExtendedLongUpDownCounter;
-import io.opentelemetry.api.incubator.trace.ExtendedSpanBuilder;
 import io.opentelemetry.api.incubator.trace.ExtendedTracer;
 import io.opentelemetry.api.logs.LoggerProvider;
 import io.opentelemetry.api.metrics.Meter;
@@ -53,7 +51,7 @@ void incubatingLogSdk() {
 
     ExtendedLogger logger = (ExtendedLogger) loggerProvider.get("logger");
     logger.isEnabled();
-    ((ExtendedLogRecordBuilder) logger.logRecordBuilder()).setBody("message").emit();
+    logger.logRecordBuilder().setBody("message").emit();
   }
 
   @Test
@@ -64,7 +62,7 @@ void incubatingTraceSdk() {
 
     ExtendedTracer tracer = (ExtendedTracer) tracerProvider.get("tracer");
     tracer.isEnabled();
-    ((ExtendedSpanBuilder) tracer.spanBuilder("span")).startAndRun(() -> {});
+    tracer.spanBuilder("span").startAndRun(() -> {});
   }
 
   @Test

sdk/trace/src/main/java/io/opentelemetry/sdk/trace/ExtendedSdkTracer.java

@@ -5,6 +5,7 @@
 
 package io.opentelemetry.sdk.trace;
 
+import io.opentelemetry.api.incubator.trace.ExtendedSpanBuilder;
 import io.opentelemetry.api.incubator.trace.ExtendedTracer;
 import io.opentelemetry.sdk.common.InstrumentationScopeInfo;
 import io.opentelemetry.sdk.trace.internal.TracerConfig;
@@ -27,4 +28,9 @@ final class ExtendedSdkTracer extends SdkTracer implements ExtendedTracer {
   public boolean isEnabled() {
     return tracerEnabled;
   }
+
+  @Override
+  public ExtendedSpanBuilder spanBuilder(String spanName) {
+    return (ExtendedSpanBuilder) super.spanBuilder(spanName);
+  }
 }

sdk/trace/src/main/java/io/opentelemetry/sdk/trace/SdkTracer.java

@@ -53,6 +53,10 @@ static SdkTracer create(
         : new SdkTracer(sharedState, instrumentationScopeInfo, tracerConfig);
   }
 
+  /**
+   * Note that {@link ExtendedSdkTracer#spanBuilder(String)} calls this and depends on it returning
+   * {@link ExtendedSdkTracer} in all cases when the incubator is present.
+   */
   @Override
   public SpanBuilder spanBuilder(String spanName) {
     if (!tracerEnabled) {
@@ -62,8 +66,7 @@ public SpanBuilder spanBuilder(String spanName) {
       spanName = FALLBACK_SPAN_NAME;
     }
     if (sharedState.hasBeenShutdown()) {
-      Tracer tracer = TracerProvider.noop().get(instrumentationScopeInfo.getName());
-      return tracer.spanBuilder(spanName);
+      return NOOP_TRACER.spanBuilder(spanName);
     }
     return INCUBATOR_AVAILABLE
         ? IncubatingUtil.createExtendedSpanBuilder(

sdk/trace/src/testIncubating/java/io/opentelemetry/sdk/trace/ExtendedTracerTest.java

@@ -0,0 +1,71 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.sdk.trace;
+
+import static io.opentelemetry.sdk.internal.ScopeConfiguratorBuilder.nameEquals;
+import static io.opentelemetry.sdk.testing.assertj.OpenTelemetryAssertions.assertThat;
+import static io.opentelemetry.sdk.trace.internal.TracerConfig.disabled;
+
+import io.opentelemetry.api.incubator.trace.ExtendedSpanBuilder;
+import io.opentelemetry.api.incubator.trace.ExtendedTracer;
+import io.opentelemetry.sdk.testing.exporter.InMemorySpanExporter;
+import io.opentelemetry.sdk.trace.export.SimpleSpanProcessor;
+import java.util.function.Supplier;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class ExtendedTracerTest {
+
+  /**
+   * {@link ExtendedTracer#spanBuilder(String)} delegates to {@link SdkTracer#spanBuilder(String)}
+   * and casts the result to {@link ExtendedSpanBuilder}. Therefore, we need to confirm that {@link
+   * SdkTracer#spanBuilder(String)} correctly returns {@link ExtendedSpanBuilder} and not {@link
+   * io.opentelemetry.api.trace.SpanBuilder} in all cases, else the user will get {@link
+   * ClassCastException}.
+   */
+  @ParameterizedTest
+  @MethodSource("spanBuilderArgs")
+  void spanBuilder(Supplier<ExtendedSpanBuilder> spanBuilderSupplier) {
+    ExtendedSpanBuilder spanBuilder = spanBuilderSupplier.get();
+    assertThat(spanBuilder).isInstanceOf(ExtendedSpanBuilder.class);
+  }
+
+  private static Stream<Arguments> spanBuilderArgs() {
+    SdkTracerProvider tracerProvider =
+        SdkTracerProvider.builder()
+            .addSpanProcessor(SimpleSpanProcessor.create(InMemorySpanExporter.create()))
+            .addTracerConfiguratorCondition(nameEquals("tracerB"), disabled())
+            .build();
+
+    ExtendedTracer tracerA = (ExtendedTracer) tracerProvider.get("tracerA");
+    ExtendedTracer tracerB = (ExtendedTracer) tracerProvider.get("tracerB");
+
+    SdkTracerProvider tracerProvider2 =
+        SdkTracerProvider.builder()
+            .addSpanProcessor(SimpleSpanProcessor.create(InMemorySpanExporter.create()))
+            .build();
+    ExtendedTracer tracerC = (ExtendedTracer) tracerProvider.get("tracerC");
+    tracerProvider2.shutdown();
+
+    return Stream.of(
+        // Simple case
+        Arguments.of(spanBuilderSupplier(() -> tracerA.spanBuilder("span"))),
+        // Disabled tracer
+        Arguments.of(spanBuilderSupplier(() -> tracerB.spanBuilder("span"))),
+        // Invalid span name
+        Arguments.of(spanBuilderSupplier(() -> tracerB.spanBuilder(null))),
+        Arguments.of(spanBuilderSupplier(() -> tracerB.spanBuilder(" "))),
+        // Shutdown tracer provider
+        Arguments.of(spanBuilderSupplier(() -> tracerC.spanBuilder("span"))));
+  }
+
+  private static Supplier<ExtendedSpanBuilder> spanBuilderSupplier(
+      Supplier<ExtendedSpanBuilder> spanBuilderSupplier) {
+    return spanBuilderSupplier;
+  }
+}