Promote getAll to TextMapGetter stable API (#7267)

Author: jack-berg

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

@@ -16,7 +16,6 @@
 import io.opentelemetry.context.propagation.TextMapGetter;
 import io.opentelemetry.context.propagation.TextMapPropagator;
 import io.opentelemetry.context.propagation.TextMapSetter;
-import io.opentelemetry.context.propagation.internal.ExtendedTextMapGetter;
 import java.util.Collection;
 import java.util.Iterator;
 import java.util.List;
@@ -97,33 +96,11 @@ public <C> Context extract(Context context, @Nullable C carrier, TextMapGetter<C
       return context;
     }
 
-    if (getter instanceof ExtendedTextMapGetter) {
-      return extractMulti(context, carrier, (ExtendedTextMapGetter<C>) getter);
-    }
-    return extractSingle(context, carrier, getter);
-  }
-
-  private static <C> Context extractSingle(
-      Context context, @Nullable C carrier, TextMapGetter<C> getter) {
-    String baggageHeader = getter.get(carrier, FIELD);
-    if (baggageHeader == null) {
-      return context;
-    }
-    if (baggageHeader.isEmpty()) {
-      return context;
-    }
-
-    BaggageBuilder baggageBuilder = Baggage.builder();
-    try {
-      extractEntries(baggageHeader, baggageBuilder);
-    } catch (RuntimeException e) {
-      return context;
-    }
-    return context.with(baggageBuilder.build());
+    return extractMulti(context, carrier, getter);
   }
 
   private static <C> Context extractMulti(
-      Context context, @Nullable C carrier, ExtendedTextMapGetter<C> getter) {
+      Context context, @Nullable C carrier, TextMapGetter<C> getter) {
     Iterator<String> baggageHeaders = getter.getAll(carrier, FIELD);
     if (baggageHeaders == null) {
       return context;

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

@@ -14,7 +14,6 @@
 import io.opentelemetry.api.baggage.BaggageEntryMetadata;
 import io.opentelemetry.context.Context;
 import io.opentelemetry.context.propagation.TextMapGetter;
-import io.opentelemetry.context.propagation.internal.ExtendedTextMapGetter;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Iterator;
@@ -40,8 +39,8 @@ public String get(Map<String, String> carrier, String key) {
         }
       };
 
-  private static final ExtendedTextMapGetter<Map<String, List<String>>> multiGetter =
-      new ExtendedTextMapGetter<Map<String, List<String>>>() {
+  private static final TextMapGetter<Map<String, List<String>>> multiGetter =
+      new TextMapGetter<Map<String, List<String>>>() {
         @Override
         public Iterable<String> keys(Map<String, List<String>> carrier) {
           return carrier.keySet();

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

@@ -5,6 +5,8 @@
 
 package io.opentelemetry.context.propagation;
 
+import java.util.Collections;
+import java.util.Iterator;
 import javax.annotation.Nullable;
 
 /**
@@ -33,4 +35,23 @@ public interface TextMapGetter<C> {
    */
   @Nullable
   String get(@Nullable C carrier, String key);
+
+  /**
+   * If implemented, returns all values for a given {@code key} in order, or returns an empty list.
+   *
+   * <p>The default method returns the first value of the given propagation {@code key} as a
+   * singleton list, or returns an empty list.
+   *
+   * @param carrier carrier of propagation fields, such as an http request.
+   * @param key the key of the field.
+   * @return all values for a given {@code key} in order, or returns an empty list. Default method
+   *     wraps {@code get()} as an {@link Iterator}.
+   */
+  default Iterator<String> getAll(@Nullable C carrier, String key) {
+    String first = get(carrier, key);
+    if (first == null) {
+      return Collections.emptyIterator();
+    }
+    return Collections.singleton(first).iterator();
+  }
 }

context/src/main/java/io/opentelemetry/context/propagation/internal/ExtendedTextMapGetter.java

@@ -6,39 +6,16 @@
 package io.opentelemetry.context.propagation.internal;
 
 import io.opentelemetry.context.propagation.TextMapGetter;
-import java.util.Collections;
-import java.util.Iterator;
-import javax.annotation.Nullable;
 
 /**
- * Extends {@link TextMapGetter} to return possibly multiple values for a given key.
+ * Extended {@link TextMapGetter} with experimental APIs.
  *
  * <p>This class is internal and experimental. Its APIs are unstable and can change at any time. Its
  * APIs (or a version of them) may be promoted to the public stable API in the future, but no
  * guarantees are made.
- *
- * @param <C> carrier of propagation fields, such as an http request.
  */
 public interface ExtendedTextMapGetter<C> extends TextMapGetter<C> {
-  /**
-   * If implemented, returns all values for a given {@code key} in order, or returns an empty list.
-   *
-   * <p>The default method returns the first value of the given propagation {@code key} as a
-   * singleton list, or returns an empty list.
-   *
-   * <p>This class is internal and is hence not for public use. Its APIs are unstable and can change
-   * at any time.
-   *
-   * @param carrier carrier of propagation fields, such as an http request.
-   * @param key the key of the field.
-   * @return all values for a given {@code key} in order, or returns an empty list. Default method
-   *     wraps {@code get()} as an {@link Iterator}.
-   */
-  default Iterator<String> getAll(@Nullable C carrier, String key) {
-    String first = get(carrier, key);
-    if (first == null) {
-      return Collections.emptyIterator();
-    }
-    return Collections.singleton(first).iterator();
-  }
+
+  // keep this class even if it is empty, since experimental methods may be added in the future.
+
 }

context/src/test/java/io/opentelemetry/context/propagation/internal/ExtendedTextMapGetterTest.java renamed to context/src/test/java/io/opentelemetry/context/propagation/TextMapGetterTest.java

@@ -3,21 +3,22 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-package io.opentelemetry.context.propagation.internal;
+package io.opentelemetry.context.propagation;
 
 import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
 
 import com.google.common.collect.ImmutableList;
+import io.opentelemetry.context.propagation.internal.ExtendedTextMapGetter;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 import javax.annotation.Nullable;
 import org.junit.jupiter.api.Test;
 
-class ExtendedTextMapGetterTest {
+class TextMapGetterTest {
 
-  final ExtendedTextMapGetter<Void> nullGet =
+  final TextMapGetter<Void> nullGet =
       new ExtendedTextMapGetter<Void>() {
         @Override
         public Iterable<String> keys(Void carrier) {
@@ -31,7 +32,7 @@ public String get(@Nullable Void carrier, String key) {
         }
       };
 
-  final ExtendedTextMapGetter<Void> nonNullGet =
+  final TextMapGetter<Void> nonNullGet =
       new ExtendedTextMapGetter<Void>() {
         @Override
         public Iterable<String> keys(Void carrier) {

docs/apidiffs/current_vs_latest/opentelemetry-context.txt

@@ -1,2 +1,5 @@
 Comparing source compatibility of opentelemetry-context-1.50.0-SNAPSHOT.jar against opentelemetry-context-1.49.0.jar
-No changes.
+***  MODIFIED INTERFACE: PUBLIC ABSTRACT io.opentelemetry.context.propagation.TextMapGetter  (not serializable)
+	===  CLASS FILE FORMAT VERSION: 52.0 <- 52.0
+	GENERIC TEMPLATES: === C:java.lang.Object
+	+++  NEW METHOD: PUBLIC(+) java.util.Iterator<java.lang.String> getAll(java.lang.Object, java.lang.String)