TracerProvider: Make format settable.

api/src/main/java/io/opentelemetry/trace/propagation/BinaryTraceContext.java

@@ -93,6 +93,12 @@ public final class BinaryTraceContext implements BinaryFormat<SpanContext> {
   private static final int ALL_FORMAT_LENGTH =
       REQUIRED_FORMAT_LENGTH + ID_SIZE + TraceFlags.getSize();
 
+  private static final BinaryTraceContext INSTANCE = new BinaryTraceContext();
+
+  public static BinaryTraceContext getInstance() {
+    return INSTANCE;
+  }
+
   @Override
   public byte[] toByteArray(SpanContext spanContext) {
     Utils.checkNotNull(spanContext, "spanContext");

api/src/main/java/io/opentelemetry/trace/propagation/HttpTraceContext.java

@@ -63,6 +63,12 @@ public class HttpTraceContext implements HttpTextFormat<SpanContext> {
   private static final Pattern TRACESTATE_ENTRY_DELIMITER_SPLIT_PATTERN =
       Pattern.compile("[ \t]*" + TRACESTATE_ENTRY_DELIMITER + "[ \t]*");
 
+  private static final HttpTraceContext INSTANCE = new HttpTraceContext();
+
+  public static HttpTraceContext getInstance() {
+    return INSTANCE;
+  }
+
   @Override
   public List<String> fields() {
     return FIELDS;

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

@@ -24,14 +24,10 @@
 import io.opentelemetry.trace.Span;
 import io.opentelemetry.trace.SpanContext;
 import io.opentelemetry.trace.Tracer;
-import io.opentelemetry.trace.propagation.BinaryTraceContext;
-import io.opentelemetry.trace.propagation.HttpTraceContext;
 import io.opentelemetry.trace.unsafe.ContextUtils;
 
 /** {@link TracerSdk} is SDK implementation of {@link Tracer}. */
 public final class TracerSdk implements Tracer {
-  private static final BinaryFormat<SpanContext> BINARY_FORMAT = new BinaryTraceContext();
-  private static final HttpTextFormat<SpanContext> HTTP_TEXT_FORMAT = new HttpTraceContext();
   private final TracerSharedState sharedState;
   private final InstrumentationLibraryInfo instrumentationLibraryInfo;
 
@@ -67,12 +63,12 @@ public Span.Builder spanBuilder(String spanName) {
 
   @Override
   public BinaryFormat<SpanContext> getBinaryFormat() {
-    return BINARY_FORMAT;
+    return sharedState.getBinaryFormat();
   }
 
   @Override
   public HttpTextFormat<SpanContext> getHttpTextFormat() {
-    return HTTP_TEXT_FORMAT;
+    return sharedState.getTextFormat();
   }
 
   /**

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

@@ -16,6 +16,8 @@
 
 package io.opentelemetry.sdk.trace;
 
+import io.opentelemetry.context.propagation.BinaryFormat;
+import io.opentelemetry.context.propagation.HttpTextFormat;
 import io.opentelemetry.internal.Utils;
 import io.opentelemetry.sdk.common.Clock;
 import io.opentelemetry.sdk.common.InstrumentationLibraryInfo;
@@ -24,8 +26,11 @@
 import io.opentelemetry.sdk.resources.EnvVarResource;
 import io.opentelemetry.sdk.resources.Resource;
 import io.opentelemetry.sdk.trace.config.TraceConfig;
+import io.opentelemetry.trace.SpanContext;
 import io.opentelemetry.trace.Tracer;
 import io.opentelemetry.trace.TracerProvider;
+import io.opentelemetry.trace.propagation.BinaryTraceContext;
+import io.opentelemetry.trace.propagation.HttpTraceContext;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
@@ -50,8 +55,14 @@ public static Builder builder() {
     return new Builder();
   }
 
-  private TracerSdkProvider(Clock clock, IdsGenerator idsGenerator, Resource resource) {
-    this.sharedState = new TracerSharedState(clock, idsGenerator, resource);
+  private TracerSdkProvider(
+      Clock clock,
+      IdsGenerator idsGenerator,
+      Resource resource,
+      HttpTextFormat<SpanContext> textFormat,
+      BinaryFormat<SpanContext> binaryFormat) {
+    this.sharedState =
+        new TracerSharedState(clock, idsGenerator, resource, textFormat, binaryFormat);
     this.tracerSdkComponentRegistry = new TracerSdkComponentRegistry(sharedState);
   }
 
@@ -124,6 +135,8 @@ public static class Builder {
     private Clock clock = MillisClock.getInstance();
     private IdsGenerator idsGenerator = new RandomIdsGenerator();
     private Resource resource = EnvVarResource.getResource();
+    private HttpTextFormat<SpanContext> textFormat = HttpTraceContext.getInstance();
+    private BinaryFormat<SpanContext> binaryFormat = BinaryTraceContext.getInstance();
 
     /**
      * Assign a {@link Clock}.
@@ -163,12 +176,36 @@ public Builder setResource(Resource resource) {
     }
 
     /**
-     * Create a new TracerSdkFactory instance.
+     * Assign an {@link HttpTextFormat}.
      *
-     * @return An initialized TracerSdkFactory.
+     * @param textFormat The text format to use for propagation.
+     * @return this
+     */
+    public Builder setTextFormat(HttpTextFormat<SpanContext> textFormat) {
+      Utils.checkNotNull(textFormat, "textFormat");
+      this.textFormat = textFormat;
+      return this;
+    }
+
+    /**
+     * Assign a {@link BinaryFormat}.
+     *
+     * @param binaryFormat The binary format to use for propagation.
+     * @return this
+     */
+    public Builder setBinaryFormat(BinaryFormat<SpanContext> binaryFormat) {
+      Utils.checkNotNull(binaryFormat, "binaryFormat");
+      this.binaryFormat = binaryFormat;
+      return this;
+    }
+
+    /**
+     * Create a new TracerSdkProvider instance.
+     *
+     * @return An initialized TracerSdkProvider.
      */
     public TracerSdkProvider build() {
-      return new TracerSdkProvider(clock, idsGenerator, resource);
+      return new TracerSdkProvider(clock, idsGenerator, resource, textFormat, binaryFormat);
     }
 
     private Builder() {}

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

@@ -16,9 +16,12 @@
 
 package io.opentelemetry.sdk.trace;
 
+import io.opentelemetry.context.propagation.BinaryFormat;
+import io.opentelemetry.context.propagation.HttpTextFormat;
 import io.opentelemetry.sdk.common.Clock;
 import io.opentelemetry.sdk.resources.Resource;
 import io.opentelemetry.sdk.trace.config.TraceConfig;
+import io.opentelemetry.trace.SpanContext;
 import java.util.ArrayList;
 import java.util.List;
 import javax.annotation.concurrent.GuardedBy;
@@ -29,6 +32,8 @@ final class TracerSharedState {
   private final Clock clock;
   private final IdsGenerator idsGenerator;
   private final Resource resource;
+  private final HttpTextFormat<SpanContext> textFormat;
+  private final BinaryFormat<SpanContext> binaryFormat;
 
   // Reads and writes are atomic for reference variables. Use volatile to ensure that these
   // operations are visible on other CPUs as well.
@@ -39,10 +44,17 @@ final class TracerSharedState {
   @GuardedBy("lock")
   private final List<SpanProcessor> registeredSpanProcessors = new ArrayList<>();
 
-  TracerSharedState(Clock clock, IdsGenerator idsGenerator, Resource resource) {
+  TracerSharedState(
+      Clock clock,
+      IdsGenerator idsGenerator,
+      Resource resource,
+      HttpTextFormat<SpanContext> textFormat,
+      BinaryFormat<SpanContext> binaryFormat) {
     this.clock = clock;
     this.idsGenerator = idsGenerator;
     this.resource = resource;
+    this.textFormat = textFormat;
+    this.binaryFormat = binaryFormat;
   }
 
   Clock getClock() {
@@ -57,6 +69,10 @@ Resource getResource() {
     return resource;
   }
 
+  HttpTextFormat<SpanContext> getTextFormat() {
+    return textFormat;
+  }
+
   /**
    * Returns the active {@code TraceConfig}.
    *
@@ -117,4 +133,8 @@ void stop() {
       isStopped = true;
     }
   }
+
+  public BinaryFormat<SpanContext> getBinaryFormat() {
+    return binaryFormat;
+  }
 }

sdk/src/test/java/io/opentelemetry/sdk/trace/TracerSdkProviderTest.java

@@ -19,12 +19,15 @@
 import static com.google.common.truth.Truth.assertThat;
 import static org.mockito.Mockito.mock;
 
+import io.opentelemetry.context.propagation.BinaryFormat;
+import io.opentelemetry.context.propagation.HttpTextFormat;
 import io.opentelemetry.sdk.common.Clock;
 import io.opentelemetry.sdk.common.InstrumentationLibraryInfo;
 import io.opentelemetry.sdk.resources.Resource;
 import io.opentelemetry.sdk.trace.config.TraceConfig;
 import io.opentelemetry.trace.DefaultSpan;
 import io.opentelemetry.trace.Span;
+import io.opentelemetry.trace.SpanContext;
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
@@ -80,6 +83,36 @@ public void builder_NullIdsGenerator() {
     TracerSdkProvider.builder().setIdsGenerator(null);
   }
 
+  @Test
+  public void builder_NullTextFormat() {
+    thrown.expect(NullPointerException.class);
+    thrown.expectMessage("textFormat");
+    TracerSdkProvider.builder().setTextFormat(null);
+  }
+
+  @Test
+  public void builder_NullBinaryFormat() {
+    thrown.expect(NullPointerException.class);
+    thrown.expectMessage("binaryFormat");
+    TracerSdkProvider.builder().setBinaryFormat(null);
+  }
+
+  @Test
+  public void builder_setTextFormat() {
+    @SuppressWarnings("unchecked")
+    final HttpTextFormat<SpanContext> format = Mockito.mock(HttpTextFormat.class);
+    final TracerSdkProvider registry = TracerSdkProvider.builder().setTextFormat(format).build();
+    assertThat(registry.get("test").getHttpTextFormat()).isSameInstanceAs(format);
+  }
+
+  @Test
+  public void builder_setBinaryFormat() {
+    @SuppressWarnings("unchecked")
+    final BinaryFormat<SpanContext> format = Mockito.mock(BinaryFormat.class);
+    final TracerSdkProvider registry = TracerSdkProvider.builder().setBinaryFormat(format).build();
+    assertThat(registry.get("test").getBinaryFormat()).isSameInstanceAs(format);
+  }
+
   @Test
   public void defaultGet() {
     assertThat(tracerFactory.get("test")).isInstanceOf(TracerSdk.class);