core: annotate some keys with Immutable; Context.Key final
diff --git a/context/src/main/java/io/grpc/Context.java b/context/src/main/java/io/grpc/Context.java
index a9bcea6..af4417a 100644
--- a/context/src/main/java/io/grpc/Context.java
+++ b/context/src/main/java/io/grpc/Context.java
@@ -803,7 +803,7 @@
/**
* Key for indexing values stored in a context.
*/
- public static class Key<T> {
+ public static final class Key<T> {
private final String name;
private final T defaultValue;
diff --git a/core/src/main/java/io/grpc/Attributes.java b/core/src/main/java/io/grpc/Attributes.java
index b31a442..0ea8de2 100644
--- a/core/src/main/java/io/grpc/Attributes.java
+++ b/core/src/main/java/io/grpc/Attributes.java
@@ -85,6 +85,11 @@
return new Builder();
}
+ /**
+ * Key for an key-value pair.
+ * @param <T> type of the value in the key-value pair
+ */
+ @Immutable
public static final class Key<T> {
private final String name;
diff --git a/core/src/main/java/io/grpc/Metadata.java b/core/src/main/java/io/grpc/Metadata.java
index e133ca2..3b439de 100644
--- a/core/src/main/java/io/grpc/Metadata.java
+++ b/core/src/main/java/io/grpc/Metadata.java
@@ -52,6 +52,7 @@
import java.util.NoSuchElementException;
import java.util.Set;
import javax.annotation.Nullable;
+import javax.annotation.concurrent.Immutable;
import javax.annotation.concurrent.NotThreadSafe;
/**
@@ -565,10 +566,14 @@
* <p>Note this has to be the subset of valid HTTP/2 token characters as defined in RFC7230
* Section 3.2.6 and RFC5234 Section B.1
*
+ * <p>Note that a key is immutable but it may not be deeply immutable, because the key depends on
+ * its marshaller, and the marshaller can be mutable though not recommended.
+ *
* @see <a href="https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md">Wire Spec</a>
* @see <a href="https://tools.ietf.org/html/rfc7230#section-3.2.6">RFC7230</a>
* @see <a href="https://tools.ietf.org/html/rfc5234#appendix-B.1">RFC5234</a>
*/
+ @Immutable
public abstract static class Key<T> {
/** Valid characters for field names as defined in RFC7230 and RFC5234. */
@@ -787,6 +792,7 @@
* A specialized plain ASCII marshaller. Both input and output are assumed to be valid header
* ASCII.
*/
+ @Immutable
interface TrustedAsciiMarshaller<T> {
/**
* Serialize a metadata value to a ASCII string that contains only the characters listed in the
