Adds Baggage.getEntry(String key) (#6765)

Co-authored-by: Trask Stalnaker <[email protected]>
Co-authored-by: Jack Berg <[email protected]>

Author: 3 people

api/all/src/main/java/io/opentelemetry/api/baggage/Baggage.java

@@ -99,4 +99,22 @@ default boolean isEmpty() {
    * be set to not use an implicit parent, so any parent assignment must be done manually.
    */
   BaggageBuilder toBuilder();
+
+  /**
+   * Returns the {@code BaggageEntry} associated with the given key.
+   *
+   * @param entryKey entry key to return the {@code BaggageEntry} for, or {@code null} if no {@code
+   *     Entry} with the given {@code entryKey} is in this {@code Baggage}.
+   */
+  @Nullable
+  default BaggageEntry getEntry(String entryKey) {
+    BaggageEntry[] result = new BaggageEntry[] {null};
+    forEach(
+        (key, entry) -> {
+          if (entryKey.equals(key)) {
+            result[0] = entry;
+          }
+        });
+    return result[0];
+  }
 }

api/all/src/main/java/io/opentelemetry/api/baggage/ImmutableBaggage.java

@@ -37,6 +37,13 @@ public String getEntryValue(String entryKey) {
     return entry != null ? entry.getValue() : null;
   }
 
+  // Overrides the default implementation to provide a more performant implementation.
+  @Nullable
+  @Override
+  public BaggageEntry getEntry(String entryKey) {
+    return get(entryKey);
+  }
+
   @Override
   public BaggageBuilder toBuilder() {
     return new Builder(new ArrayList<>(data()));

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

@@ -37,7 +37,7 @@ private enum State {
 
   private boolean skipToNext;
 
-  public Parser(String baggageHeader) {
+  Parser(String baggageHeader) {
     this.baggageHeader = baggageHeader;
     reset(0);
   }

api/all/src/test/java/io/opentelemetry/api/baggage/BaggageTest.java

@@ -9,6 +9,10 @@
 
 import io.opentelemetry.context.Context;
 import io.opentelemetry.context.Scope;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.function.BiConsumer;
+import javax.annotation.Nullable;
 import org.junit.jupiter.api.Test;
 
 class BaggageTest {
@@ -27,4 +31,45 @@ void current() {
       assertThat(result.getEntryValue("foo")).isEqualTo("bar");
     }
   }
+
+  @Test
+  void getEntryDefault() {
+    BaggageEntryMetadata metadata = BaggageEntryMetadata.create("flib");
+    Map<String, BaggageEntry> result = new HashMap<>();
+    result.put("a", ImmutableEntry.create("b", metadata));
+    // Implementation that only implements asMap() which is used by getEntry()
+    Baggage baggage =
+        new Baggage() {
+
+          @Override
+          public Map<String, BaggageEntry> asMap() {
+            return result;
+          }
+
+          @Override
+          public int size() {
+            return 0;
+          }
+
+          @Override
+          public void forEach(BiConsumer<? super String, ? super BaggageEntry> consumer) {
+            result.forEach(consumer);
+          }
+
+          @Nullable
+          @Override
+          public String getEntryValue(String entryKey) {
+            return null;
+          }
+
+          @Override
+          public BaggageBuilder toBuilder() {
+            return null;
+          }
+        };
+
+    BaggageEntry entry = baggage.getEntry("a");
+    assertThat(entry.getValue()).isEqualTo("b");
+    assertThat(entry.getMetadata().getValue()).isEqualTo("flib");
+  }
 }

api/all/src/test/java/io/opentelemetry/api/baggage/ImmutableBaggageTest.java

@@ -9,6 +9,8 @@
 import static org.assertj.core.api.Assertions.entry;
 
 import com.google.common.testing.EqualsTester;
+import io.opentelemetry.context.Context;
+import io.opentelemetry.context.Scope;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -190,4 +192,15 @@ void testEquals() {
         .addEqualityGroup(baggage2, baggage3)
         .testEquals();
   }
+
+  @Test
+  void getEntry() {
+    BaggageEntryMetadata metadata = BaggageEntryMetadata.create("flib");
+    try (Scope scope =
+        Context.root().with(Baggage.builder().put("a", "b", metadata).build()).makeCurrent()) {
+      Baggage result = Baggage.current();
+      assertThat(result.getEntry("a").getValue()).isEqualTo("b");
+      assertThat(result.getEntry("a").getMetadata().getValue()).isEqualTo("flib");
+    }
+  }
 }

docs/apidiffs/current_vs_latest/opentelemetry-api.txt

@@ -1,2 +1,5 @@
 Comparing source compatibility of opentelemetry-api-1.43.0-SNAPSHOT.jar against opentelemetry-api-1.42.1.jar
-No changes.
+***  MODIFIED INTERFACE: PUBLIC ABSTRACT io.opentelemetry.api.baggage.Baggage  (not serializable)
+	===  CLASS FILE FORMAT VERSION: 52.0 <- 52.0
+	+++  NEW METHOD: PUBLIC(+) io.opentelemetry.api.baggage.BaggageEntry getEntry(java.lang.String)
+		+++  NEW ANNOTATION: javax.annotation.Nullable