HADOOP-15704. Mark ABFS extension package and interfaces as LimitedPrivate/Unstable.

Contributed by Steve Loughran.

hadoop-tools/hadoop-azure/src/main/java/org/apache/hadoop/fs/azurebfs/extensions/CustomDelegationTokenManager.java

@@ -21,6 +21,8 @@ package org.apache.hadoop.fs.azurebfs.extensions;
 
 import java.io.IOException;
 
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.classification.InterfaceStability;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.security.token.delegation.web.DelegationTokenIdentifier;
 import org.apache.hadoop.security.token.Token;
@@ -28,6 +30,8 @@ import org.apache.hadoop.security.token.Token;
 /**
  * Interface for Managing the Delegation tokens.
  */
+@InterfaceAudience.LimitedPrivate("authorization-subsystems")
+@InterfaceStability.Unstable
 public interface CustomDelegationTokenManager {
 
   /**

hadoop-tools/hadoop-azure/src/main/java/org/apache/hadoop/fs/azurebfs/extensions/CustomTokenProviderAdaptee.java

@@ -35,8 +35,8 @@ import org.apache.hadoop.conf.Configuration;
  * This class will be dynamically loaded, initialized, and invoked to provide
  * AAD Access Tokens and their Expiry.
  */
-@InterfaceAudience.Public
-@InterfaceStability.Evolving
+@InterfaceAudience.LimitedPrivate("authorization-subsystems")
+@InterfaceStability.Unstable
 public interface CustomTokenProviderAdaptee {
 
   /**

hadoop-tools/hadoop-azure/src/main/java/org/apache/hadoop/fs/azurebfs/extensions/package-info.java

@@ -16,6 +16,17 @@
  * limitations under the License.
  */
 
-@InterfaceAudience.Public
+/**
+ * This package is for extension points under ABFS;
+ * There are no stability guarantees as these extension points are
+ * deep inside the ABFS implementation code.
+ *
+ * Note, however: this is how the ABFS client integrates with
+ * authorization services and other aspects of Azure's infrastructure.
+ * Do not change these APIs without good reason or detailed discussion.
+ */
+@InterfaceAudience.LimitedPrivate("authorization-subsystems")
+@InterfaceStability.Unstable
 package org.apache.hadoop.fs.azurebfs.extensions;
 import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.classification.InterfaceStability;