Refined TransactionData based on review comments

community/graphdb-api/src/main/java/org/neo4j/graphdb/event/TransactionData.java

@@ -167,16 +167,16 @@ public interface TransactionData
     /**
      * Get the username under which authorization state this transaction is running.
      *
-     * @return name of subject
+     * @return the username of the user who initiated the transaction.
      */
-    String getUsername();
+    String username();
 
     /**
      * Applications that start transactions may attach additional application specific meta-data to each transaction.
      *
-     * @return The application specific meta-data map associated with this transaction
+     * @return The application specific meta-data map associated with this transaction.
      */
-    Map<String,Object> getMetaData();
+    Map<String,Object> metaData();
 
     /**
      * Return transaction id that assigned during transaction commit process.

community/kernel/src/main/java/org/neo4j/kernel/impl/coreapi/TxStateTransactionDataSnapshot.java

@@ -158,13 +158,13 @@ public Iterable<PropertyEntry<Relationship>> removedRelationshipProperties()
     }
 
     @Override
-    public String getUsername()
+    public String username()
     {
         return transaction.mode().username();
     }
 
     @Override
-    public Map<String,Object> getMetaData()
+    public Map<String,Object> metaData()
     {
         if ( transaction instanceof KernelTransactionImplementation )
         {

community/kernel/src/main/java/org/neo4j/kernel/internal/TransactionEventHandlers.java

@@ -286,15 +286,15 @@ public boolean isDeleted( Relationship relationship )
         }
 
         @Override
-        public String getUsername()
+        public String username()
         {
             return "";
         }
 
         @Override
-        public Map<String,Object> getMetaData()
+        public Map<String,Object> metaData()
         {
-            return Collections.EMPTY_MAP;
+            return Collections.emptyMap();
         }
 
         @Override

community/kernel/src/test/java/org/neo4j/kernel/impl/coreapi/TxStateTransactionDataViewTest.java

@@ -310,7 +310,7 @@ public void shouldNotAccessUsernameFromStaticAccessMode()
         when( transaction.mode() ).thenReturn( accessMode );
 
         TxStateTransactionDataSnapshot transactionDataSnapshot = snapshot();
-        assertEquals( "", transactionDataSnapshot.getUsername() );
+        assertEquals( "", transactionDataSnapshot.username() );
     }
 
     @Test
@@ -321,14 +321,14 @@ public void shouldAccessUsernameFromAuthSubject()
         when( transaction.mode() ).thenReturn( authSubject );
 
         TxStateTransactionDataSnapshot transactionDataSnapshot = snapshot();
-        assertEquals( "Christof", transactionDataSnapshot.getUsername() );
+        assertEquals( "Christof", transactionDataSnapshot.username() );
     }
 
     @Test
     public void shouldAccessEmptyMetaData()
     {
         TxStateTransactionDataSnapshot transactionDataSnapshot = snapshot();
-        assertEquals( 0, transactionDataSnapshot.getMetaData().size() );
+        assertEquals( 0, transactionDataSnapshot.metaData().size() );
     }
 
     @Test
@@ -340,8 +340,8 @@ public void shouldAccessExampleMetaData()
         when( transaction.getMetaData() ).thenReturn( genericMap( "username", "Igor" ) );
         TxStateTransactionDataSnapshot transactionDataSnapshot =
                 new TxStateTransactionDataSnapshot( state, nodeActions, relActions, ops, storeStatement, transaction );
-        assertEquals( 1, transactionDataSnapshot.getMetaData().size() );
-        assertThat( "Expected metadata map to contain defined username", transactionDataSnapshot.getMetaData(),
+        assertEquals( 1, transactionDataSnapshot.metaData().size() );
+        assertThat( "Expected metadata map to contain defined username", transactionDataSnapshot.metaData(),
                 equalTo( genericMap( "username", "Igor" ) ) );
     }
 

community/kernel/src/test/java/org/neo4j/kernel/impl/event/TransactionEventsIT.java

@@ -159,8 +159,8 @@ public void commitTimeNotAccessibleBeforeCommit()
     public void shouldGetEmptyUsernameOnAuthDisabled()
     {
         db.registerTransactionEventHandler( getBeforeCommitHandler( txData -> {
-            assertThat( "Should have no username", txData.getUsername(), equalTo( "" ) );
-            assertThat( "Should have no metadata", txData.getMetaData(), equalTo( Collections.emptyMap() ) );
+            assertThat( "Should have no username", txData.username(), equalTo( "" ) );
+            assertThat( "Should have no metadata", txData.metaData(), equalTo( Collections.emptyMap() ) );
         }) );
         runTransaction();
     }
@@ -171,8 +171,8 @@ public void shouldGetSpecifiedUsernameAndMetaDataInTXData()
         final AtomicReference<String> usernameRef = new AtomicReference<>();
         final AtomicReference<Map<String,Object>> metaDataRef = new AtomicReference<>();
         db.registerTransactionEventHandler( getBeforeCommitHandler( txData -> {
-            usernameRef.set( txData.getUsername() );
-            metaDataRef.set( txData.getMetaData() );
+            usernameRef.set( txData.username() );
+            metaDataRef.set( txData.metaData() );
         } ) );
         AuthSubject subject = mock( AuthSubject.class );
         when( subject.allowsWrites() ).thenReturn( true );