Add toString implementation to various propagator components

api/all/src/main/java/io/opentelemetry/api/baggage/propagation/W3CBaggagePropagator.java

@@ -139,4 +139,9 @@ private static boolean isValidBaggageKey(String name) {
   private static boolean isValidBaggageValue(String value) {
     return value != null;
   }
+
+  @Override
+  public String toString() {
+    return "W3CBaggagePropagator";
+  }
 }

api/all/src/main/java/io/opentelemetry/api/trace/propagation/W3CTraceContextPropagator.java

@@ -213,4 +213,9 @@ private static SpanContext extractContextFromTraceParent(String traceparent) {
             OtelEncodingUtils.byteFromBase16(firstTraceFlagsChar, secondTraceFlagsChar));
     return SpanContext.createFromRemoteParent(traceId, spanId, traceFlags, TraceState.getDefault());
   }
+
+  @Override
+  public String toString() {
+    return "W3CTraceContextPropagator";
+  }
 }

api/all/src/test/java/io/opentelemetry/api/baggage/propagation/W3CBaggagePropagatorTest.java

@@ -473,4 +473,9 @@ void inject_nullSetter() {
     W3CBaggagePropagator.getInstance().inject(context, carrier, null);
     assertThat(carrier).isEmpty();
   }
+
+  @Test
+  void toString_Valid() {
+    assertThat(W3CBaggagePropagator.getInstance().toString()).isEqualTo("W3CBaggagePropagator");
+  }
 }

api/all/src/test/java/io/opentelemetry/api/trace/propagation/W3CTraceContextPropagatorTest.java

@@ -528,6 +528,11 @@ void extract_nullGetter() {
         .isSameAs(context);
   }
 
+  @Test
+  void toString_Valid() {
+    assertThat(w3cTraceContextPropagator.toString()).isEqualTo("W3CTraceContextPropagator");
+  }
+
   // Tests transplanted from the w3c test suite
 
   @ParameterizedTest

context/src/main/java/io/opentelemetry/context/propagation/DefaultContextPropagators.java

@@ -33,4 +33,9 @@ public TextMapPropagator getTextMapPropagator() {
   DefaultContextPropagators(TextMapPropagator textMapPropagator) {
     this.textMapPropagator = textMapPropagator;
   }
+
+  @Override
+  public String toString() {
+    return "DefaultContextPropagators{textMapPropagator=" + textMapPropagator + "}";
+  }
 }

context/src/main/java/io/opentelemetry/context/propagation/MultiTextMapPropagator.java

@@ -16,17 +16,17 @@
 import javax.annotation.Nullable;
 
 final class MultiTextMapPropagator implements TextMapPropagator {
-  private final TextMapPropagator[] textPropagators;
+  private final TextMapPropagator[] textMapPropagators;
   private final Collection<String> allFields;
 
-  MultiTextMapPropagator(TextMapPropagator... textPropagators) {
-    this(Arrays.asList(textPropagators));
+  MultiTextMapPropagator(TextMapPropagator... textMapPropagators) {
+    this(Arrays.asList(textMapPropagators));
   }
 
-  MultiTextMapPropagator(List<TextMapPropagator> textPropagators) {
-    this.textPropagators = new TextMapPropagator[textPropagators.size()];
-    textPropagators.toArray(this.textPropagators);
-    this.allFields = Collections.unmodifiableList(getAllFields(this.textPropagators));
+  MultiTextMapPropagator(List<TextMapPropagator> textMapPropagators) {
+    this.textMapPropagators = new TextMapPropagator[textMapPropagators.size()];
+    textMapPropagators.toArray(this.textMapPropagators);
+    this.allFields = Collections.unmodifiableList(getAllFields(this.textMapPropagators));
   }
 
   @Override
@@ -48,7 +48,7 @@ public <C> void inject(Context context, @Nullable C carrier, TextMapSetter<C> se
     if (context == null || setter == null) {
       return;
     }
-    for (TextMapPropagator textPropagator : textPropagators) {
+    for (TextMapPropagator textPropagator : textMapPropagators) {
       textPropagator.inject(context, carrier, setter);
     }
   }
@@ -61,9 +61,14 @@ public <C> Context extract(Context context, @Nullable C carrier, TextMapGetter<C
     if (getter == null) {
       return context;
     }
-    for (TextMapPropagator textPropagator : textPropagators) {
+    for (TextMapPropagator textPropagator : textMapPropagators) {
       context = textPropagator.extract(context, carrier, getter);
     }
     return context;
   }
+
+  @Override
+  public String toString() {
+    return "MultiTextMapPropagator{textMapPropagators=" + Arrays.toString(textMapPropagators) + '}';
+  }
 }

context/src/main/java/io/opentelemetry/context/propagation/NoopTextMapPropagator.java

@@ -32,4 +32,9 @@ public <C> Context extract(Context context, @Nullable C carrier, TextMapGetter<C
     }
     return context;
   }
+
+  @Override
+  public String toString() {
+    return "NoopTextMapPropagator";
+  }
 }

context/src/test/java/io/opentelemetry/context/propagation/MultiTextMapPropagatorTest.java

@@ -167,4 +167,10 @@ void inject_nullSetter() {
     new MultiTextMapPropagator(propagator1, propagator2).inject(context, carrier, null);
     assertThat(carrier).isEmpty();
   }
+
+  @Test
+  void toString_Valid() {
+    assertThat(new MultiTextMapPropagator(propagator1, propagator2).toString())
+        .isEqualTo("MultiTextMapPropagator{textMapPropagators=[propagator1, propagator2]}");
+  }
 }

context/src/test/java/io/opentelemetry/context/propagation/NoopTextMapPropagatorTest.java

@@ -63,6 +63,11 @@ void inject_nullSetter() {
     assertThat(carrier).isEmpty();
   }
 
+  @Test
+  void toString_Valid() {
+    assertThat(TextMapPropagator.noop().toString()).isEqualTo("NoopTextMapPropagator");
+  }
+
   enum MapTextMapGetter implements TextMapGetter<Map<? extends Object, ? extends Object>> {
     INSTANCE;
 

docs/apidiffs/current_vs_latest/opentelemetry-api.txt

@@ -1,2 +1,7 @@
 Comparing source compatibility of  against 
-No changes.
+***  MODIFIED CLASS: PUBLIC FINAL io.opentelemetry.api.baggage.propagation.W3CBaggagePropagator  (not serializable)
+	===  CLASS FILE FORMAT VERSION: 52.0 <- 52.0
+	+++  NEW METHOD: PUBLIC(+) java.lang.String toString()
+***  MODIFIED CLASS: PUBLIC FINAL io.opentelemetry.api.trace.propagation.W3CTraceContextPropagator  (not serializable)
+	===  CLASS FILE FORMAT VERSION: 52.0 <- 52.0
+	+++  NEW METHOD: PUBLIC(+) java.lang.String toString()

docs/apidiffs/current_vs_latest/opentelemetry-extension-trace-propagators.txt

@@ -1,2 +1,10 @@
 Comparing source compatibility of  against 
-No changes.
+***  MODIFIED CLASS: PUBLIC FINAL io.opentelemetry.extension.trace.propagation.B3Propagator  (not serializable)
+	===  CLASS FILE FORMAT VERSION: 52.0 <- 52.0
+	+++  NEW METHOD: PUBLIC(+) java.lang.String toString()
+***  MODIFIED CLASS: PUBLIC FINAL io.opentelemetry.extension.trace.propagation.JaegerPropagator  (not serializable)
+	===  CLASS FILE FORMAT VERSION: 52.0 <- 52.0
+	+++  NEW METHOD: PUBLIC(+) java.lang.String toString()
+***  MODIFIED CLASS: PUBLIC FINAL io.opentelemetry.extension.trace.propagation.OtTracePropagator  (not serializable)
+	===  CLASS FILE FORMAT VERSION: 52.0 <- 52.0
+	+++  NEW METHOD: PUBLIC(+) java.lang.String toString()

extensions/incubator/src/main/java/io/opentelemetry/extension/incubator/propagation/PassThroughPropagator.java

@@ -99,4 +99,9 @@ public <C> Context extract(Context context, @Nullable C carrier, TextMapGetter<C
     }
     return extracted != null ? context.with(EXTRACTED_KEY_VALUES, extracted) : context;
   }
+
+  @Override
+  public String toString() {
+    return "PassThroughPropagator{fields=" + fields + "}";
+  }
 }

extensions/incubator/src/test/java/io/opentelemetry/extension/incubator/propagation/PassThroughPropagatorTest.java

@@ -87,4 +87,9 @@ void nullFields() {
         .isInstanceOf(NullPointerException.class)
         .hasMessageContaining("field");
   }
+
+  @Test
+  void toString_Valid() {
+    assertThat(propagator.toString()).isEqualTo("PassThroughPropagator{fields=[animal, food]}");
+  }
 }

extensions/trace-propagators/src/main/java/io/opentelemetry/extension/trace/propagation/B3Propagator.java

@@ -123,4 +123,9 @@ public <C> Context extract(Context context, @Nullable C carrier, TextMapGetter<C
         .findFirst()
         .get();
   }
+
+  @Override
+  public String toString() {
+    return "B3Propagator{b3PropagatorInjector=" + b3PropagatorInjector + "}";
+  }
 }

extensions/trace-propagators/src/main/java/io/opentelemetry/extension/trace/propagation/B3PropagatorInjectorMultipleHeaders.java

@@ -54,4 +54,9 @@ public <C> void inject(Context context, @Nullable C carrier, TextMapSetter<C> se
   public Collection<String> fields() {
     return FIELDS;
   }
+
+  @Override
+  public String toString() {
+    return "B3PropagatorInjectorMultipleHeaders";
+  }
 }

extensions/trace-propagators/src/main/java/io/opentelemetry/extension/trace/propagation/B3PropagatorInjectorSingleHeader.java

@@ -67,4 +67,9 @@ public <C> void inject(Context context, @Nullable C carrier, TextMapSetter<C> se
   public Collection<String> fields() {
     return FIELDS;
   }
+
+  @Override
+  public String toString() {
+    return "B3PropagatorInjectorSingleHeader";
+  }
 }

extensions/trace-propagators/src/main/java/io/opentelemetry/extension/trace/propagation/JaegerPropagator.java

@@ -145,6 +145,11 @@ public <C> Context extract(Context context, @Nullable C carrier, TextMapGetter<C
     return context;
   }
 
+  @Override
+  public String toString() {
+    return "JaegerPropagator";
+  }
+
   private static <C> SpanContext getSpanContextFromHeader(
       @Nullable C carrier, TextMapGetter<C> getter) {
     String value = getter.get(carrier, PROPAGATION_HEADER);

extensions/trace-propagators/src/main/java/io/opentelemetry/extension/trace/propagation/OtTracePropagator.java

@@ -133,4 +133,9 @@ private static SpanContext buildSpanContext(
     }
     return Common.buildSpanContext(traceId, spanId, sampled);
   }
+
+  @Override
+  public String toString() {
+    return "OtTracePropagator";
+  }
 }

extensions/trace-propagators/src/test/java/io/opentelemetry/extension/trace/propagation/B3PropagatorTest.java

@@ -724,4 +724,12 @@ void inject_DebugContext_SingleHeader() {
             B3Propagator.COMBINED_HEADER,
             TRACE_ID + "-" + SPAN_ID + "-" + B3Propagator.SINGLE_HEADER_DEBUG);
   }
+
+  @Test
+  void toString_Valid() {
+    assertThat(b3Propagator.toString())
+        .isEqualTo("B3Propagator{b3PropagatorInjector=B3PropagatorInjectorMultipleHeaders}");
+    assertThat(b3PropagatorSingleHeader.toString())
+        .isEqualTo("B3Propagator{b3PropagatorInjector=B3PropagatorInjectorSingleHeader}");
+  }
 }

extensions/trace-propagators/src/test/java/io/opentelemetry/extension/trace/propagation/JaegerPropagatorTest.java

@@ -460,6 +460,11 @@ void extract_nullGetter() {
     assertThat(jaegerPropagator.extract(context, Collections.emptyMap(), null)).isSameAs(context);
   }
 
+  @Test
+  void toString_Valid() {
+    assertThat(jaegerPropagator.toString()).isEqualTo("JaegerPropagator");
+  }
+
   private static String generateTraceIdHeaderValue(
       String traceId, String spanId, char parentSpan, String sampled) {
     return traceId

extensions/trace-propagators/src/test/java/io/opentelemetry/extension/trace/propagation/OtTracePropagatorTest.java

@@ -340,4 +340,9 @@ void extract_nullGetter() {
             Context.current());
     assertThat(propagator.extract(context, Collections.emptyMap(), null)).isSameAs(context);
   }
+
+  @Test
+  void toString_Valid() {
+    assertThat(propagator.toString()).isEqualTo("OtTracePropagator");
+  }
 }

sdk/all/src/main/java/io/opentelemetry/sdk/OpenTelemetrySdk.java

@@ -80,14 +80,15 @@ public ContextPropagators getPropagators() {
 
   @Override
   public String toString() {
-    // TODO(anuraaga): Add propagators
     return "OpenTelemetrySdk{"
         + "tracerProvider="
         + tracerProvider.unobfuscate()
         + ", meterProvider="
         + meterProvider.unobfuscate()
         + ", loggerProvider="
         + loggerProvider
+        + ", propagators="
+        + propagators
         + "}";
   }
 

sdk/all/src/test/java/io/opentelemetry/sdk/OpenTelemetrySdkTest.java

@@ -326,6 +326,8 @@ void stringRepresentation() {
     when(metricExporter.toString()).thenReturn("MockMetricExporter{}");
     LogRecordExporter logRecordExporter = mock(LogRecordExporter.class);
     when(logRecordExporter.toString()).thenReturn("MockLogRecordExporter{}");
+    TextMapPropagator propagator = mock(TextMapPropagator.class);
+    when(propagator.toString()).thenReturn("MockTextMapPropagator{}");
     Resource resource =
         Resource.builder().put(AttributeKey.stringKey("service.name"), "otel-test").build();
     OpenTelemetrySdk sdk =
@@ -352,6 +354,7 @@ void stringRepresentation() {
                         SimpleLogRecordProcessor.create(
                             LogRecordExporter.composite(logRecordExporter, logRecordExporter)))
                     .build())
+            .setPropagators(ContextPropagators.create(propagator))
             .build();
 
     assertThat(sdk.toString())
@@ -376,7 +379,8 @@ void stringRepresentation() {
                 + "resource=Resource{schemaUrl=null, attributes={service.name=\"otel-test\"}}, "
                 + "logLimits=LogLimits{maxNumberOfAttributes=128, maxAttributeValueLength=2147483647}, "
                 + "logRecordProcessor=SimpleLogRecordProcessor{logRecordExporter=MultiLogRecordExporter{logRecordExporters=[MockLogRecordExporter{}, MockLogRecordExporter{}]}}"
-                + "}"
+                + "}, "
+                + "propagators=DefaultContextPropagators{textMapPropagator=MockTextMapPropagator{}}"
                 + "}");
   }
 }