Address feedback from PR review

community/kernel/src/main/java/org/neo4j/kernel/api/ExecutingQuery.java

@@ -30,21 +30,21 @@ public class ExecutingQuery
 {
     private final long queryId;
 
-    private final String authSubjectName;
+    private final String username;
     private final String queryText;
     private final Map<String, Object> queryParameters;
     private final long startTime;
 
     public ExecutingQuery(
         long queryId,
-        String authSubjectName,
+        String userNameOrNull,
         String queryText,
         Map<String,Object> queryParameters,
         long startTime
     )
     {
         this.queryId = queryId;
-        this.authSubjectName = authSubjectName;
+        this.username = userNameOrNull;
         this.queryText = queryText;
         this.queryParameters = queryParameters;
         this.startTime = startTime;
@@ -79,9 +79,9 @@ public long kernelQueryId()
         return queryId;
     }
 
-    public String authSubjectName()
+    public String username()
     {
-        return authSubjectName;
+        return username;
     }
 
     public String queryText()
@@ -103,7 +103,7 @@ public long startTime()
     public String toString()
     {
         return format(
-            "ExecutingQuery{queryId=%d, authSubjectName='%s', queryText='%s', queryParameters=%s, startTime=%d}",
-            queryId, authSubjectName, queryText, queryParameters, startTime );
+            "ExecutingQuery{queryId=%d, username='%s', queryText='%s', queryParameters=%s, startTime=%d}",
+            queryId, username == null ? "<unavailable>" : username, queryText, queryParameters, startTime );
     }
 }

community/kernel/src/main/java/org/neo4j/kernel/impl/api/KernelStatement.java

@@ -30,6 +30,8 @@
 import org.neo4j.kernel.api.TokenWriteOperations;
 import org.neo4j.kernel.api.exceptions.InvalidTransactionTypeKernelException;
 import org.neo4j.kernel.api.exceptions.Status;
+import org.neo4j.kernel.api.security.AccessMode;
+import org.neo4j.kernel.api.security.AuthSubject;
 import org.neo4j.kernel.api.txstate.LegacyIndexTransactionState;
 import org.neo4j.kernel.api.txstate.TransactionState;
 import org.neo4j.kernel.api.txstate.TxStateHolder;
@@ -201,9 +203,10 @@ final void forceClose()
         }
     }
 
-    final String authSubjectName()
+    final String username()
     {
-        return transaction.mode().name();
+        AccessMode mode = transaction.mode();
+        return ( mode instanceof AuthSubject ) ? ((AuthSubject) mode).username() : null;
     }
 
     final ExecutingQueryList executingQueryList()

community/kernel/src/main/java/org/neo4j/kernel/impl/api/StackingQueryRegistrationOperations.java

@@ -56,7 +56,7 @@ public ExecutingQuery startQueryExecution(
     {
         long queryId = lastQueryId.incrementAndGet();
         ExecutingQuery executingQuery =
-                new ExecutingQuery( queryId, statement.authSubjectName(), queryText, queryParameters, clock.millis() );
+                new ExecutingQuery( queryId, statement.username(), queryText, queryParameters, clock.millis() );
         registerExecutingQuery( statement, executingQuery );
         return executingQuery;
     }

community/security/src/main/java/org/neo4j/server/security/auth/BasicAuthSubject.java

@@ -115,7 +115,7 @@ public BasicAuthManager getAuthManager()
     @Override
     public boolean hasUsername( String username )
     {
-        return user.name().equals( username );
+        return username().equals( username );
     }
 
     @Override

enterprise/kernel/src/main/java/org/neo4j/kernel/enterprise/builtinprocs/BuiltInProcedures.java

@@ -120,13 +120,7 @@ public Stream<ConnectionResult> listConnections()
     public Stream<ConnectionResult> terminateConnectionsForUser( @Name( "username" ) String username )
             throws InvalidArgumentsException
     {
-        EnterpriseAuthSubject subject = EnterpriseAuthSubject.castOrFail( authSubject );
-        if ( !subject.isAdmin() && !subject.hasUsername( username ) )
-        {
-            throw new AuthorizationViolationException( PERMISSION_DENIED );
-        }
-
-        subject.ensureUserExistsWithName( username );
+        ensureSelfOrAdminEnterpriseAuthSubject( username );
 
         return terminateConnectionsForValidUser( username );
     }
@@ -139,7 +133,7 @@ public Stream<QueryStatusResult> listQueries() throws InvalidArgumentsException,
             .activeTransactions()
             .stream()
             .flatMap( KernelTransactionHandle::executingQueries )
-            .filter( ( query ) -> isAdminEnterpriseAuthSubject() || authSubject.hasUsername( query.authSubjectName() ) )
+            .filter( ( query ) -> isAdminEnterpriseAuthSubject() || authSubject.hasUsername( query.username() ) )
             .map( this::queryStatusResult );
     }
 
@@ -190,10 +184,10 @@ private Stream<ExecutingQuery> executingQueriesWithId( long id, KernelTransactio
     private QueryTerminationResult killQueryTransaction( Pair<KernelTransactionHandle, ExecutingQuery> pair )
     {
         ExecutingQuery query = pair.other();
-        if ( isAdminEnterpriseAuthSubject() || authSubject.hasUsername( query.authSubjectName() ) )
+        if ( isAdminEnterpriseAuthSubject() || authSubject.hasUsername( query.username() ) )
         {
             pair.first().markForTermination( Status.Transaction.Terminated );
-            return new QueryTerminationResult( queryId( query.kernelQueryId() ), query.authSubjectName() );
+            return new QueryTerminationResult( queryId( query.kernelQueryId() ), query.username() );
         }
         else
         {
@@ -293,20 +287,21 @@ private EnterpriseAuthSubject ensureSelfOrAdminEnterpriseAuthSubject( String use
             throws InvalidArgumentsException
     {
         EnterpriseAuthSubject subject = EnterpriseAuthSubject.castOrFail( authSubject );
-        subject.ensureUserExistsWithName( username );
 
         if ( subject.isAdmin() || subject.hasUsername( username ) )
         {
+            subject.ensureUserExistsWithName( username );
             return subject;
         }
+
         throw new AuthorizationViolationException( PERMISSION_DENIED );
     }
 
     private QueryStatusResult queryStatusResult( ExecutingQuery q )
     {
         return new QueryStatusResult(
             queryId( q.kernelQueryId() ),
-            q.authSubjectName(),
+            q.username(),
             q.queryText(),
             q.queryParameters(),
             q.startTime(),

enterprise/kernel/src/main/java/org/neo4j/kernel/impl/enterprise/StandardBoltConnectionTracker.java

@@ -56,8 +56,7 @@ public Set<ManagedBoltStateMachine> getActiveConnections( String owner )
         return sessions
                 .entrySet()
                 .stream()
-                .filter( entry -> entry.getValue()
-                .equals( owner ) )
+                .filter( entry -> entry.getValue().equals( owner ) )
                 .map( Map.Entry::getKey ).collect( toSet() );
     }
 }