Rename BackupNodeProtocol to JournalProtocol per Konstantin's review

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/HDFS-1073@1151671 13f79535-47bb-0310-9956-ffa450edef68

hdfs/src/java/org/apache/hadoop/hdfs/server/namenode/BackupNode.java

@@ -29,7 +29,7 @@ import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
 import org.apache.hadoop.hdfs.protocol.FSConstants;
 import org.apache.hadoop.hdfs.server.common.HdfsConstants.NamenodeRole;
 import org.apache.hadoop.hdfs.server.common.Storage;
-import org.apache.hadoop.hdfs.server.protocol.BackupNodeProtocol;
+import org.apache.hadoop.hdfs.server.protocol.JournalProtocol;
 import org.apache.hadoop.hdfs.server.protocol.BlocksWithLocations;
 import org.apache.hadoop.hdfs.server.protocol.NamenodeCommand;
 import org.apache.hadoop.hdfs.server.protocol.NamenodeProtocol;
@@ -52,7 +52,7 @@ import org.apache.hadoop.net.NetUtils;
  * </ol>
  */
 @InterfaceAudience.Private
-public class BackupNode extends NameNode implements BackupNodeProtocol {
+public class BackupNode extends NameNode implements JournalProtocol {
   private static final String BN_ADDRESS_NAME_KEY = DFSConfigKeys.DFS_NAMENODE_BACKUP_ADDRESS_KEY;
   private static final String BN_ADDRESS_DEFAULT = DFSConfigKeys.DFS_NAMENODE_BACKUP_ADDRESS_DEFAULT;
   private static final String BN_HTTP_ADDRESS_NAME_KEY = DFSConfigKeys.DFS_NAMENODE_BACKUP_HTTP_ADDRESS_KEY;
@@ -181,8 +181,8 @@ public class BackupNode extends NameNode implements BackupNodeProtocol {
   @Override
   public long getProtocolVersion(String protocol, long clientVersion)
       throws IOException {
-    if (protocol.equals(BackupNodeProtocol.class.getName())) {
-      return BackupNodeProtocol.versionID;
+    if (protocol.equals(JournalProtocol.class.getName())) {
+      return JournalProtocol.versionID;
     } else {
       return super.getProtocolVersion(protocol, clientVersion);
     }

hdfs/src/java/org/apache/hadoop/hdfs/server/namenode/EditLogBackupOutputStream.java

@@ -24,7 +24,7 @@ import java.util.Arrays;
 
 import org.apache.hadoop.hdfs.HdfsConfiguration;
 import org.apache.hadoop.hdfs.server.common.Storage;
-import org.apache.hadoop.hdfs.server.protocol.BackupNodeProtocol;
+import org.apache.hadoop.hdfs.server.protocol.JournalProtocol;
 import org.apache.hadoop.hdfs.server.protocol.NamenodeRegistration;
 import org.apache.hadoop.io.DataOutputBuffer;
 import org.apache.hadoop.io.Writable;
@@ -42,7 +42,7 @@ import org.apache.hadoop.net.NetUtils;
 class EditLogBackupOutputStream extends EditLogOutputStream {
   static int DEFAULT_BUFFER_SIZE = 256;
 
-  private BackupNodeProtocol backupNode;        // RPC proxy to backup node
+  private JournalProtocol backupNode;        // RPC proxy to backup node
   private NamenodeRegistration bnRegistration;  // backup node registration
   private NamenodeRegistration nnRegistration;  // active node registration
   private ArrayList<JournalRecord> bufCurrent;  // current buffer for writing
@@ -76,8 +76,8 @@ class EditLogBackupOutputStream extends EditLogOutputStream {
     Storage.LOG.info("EditLogBackupOutputStream connects to: " + bnAddress);
     try {
       this.backupNode =
-        RPC.getProxy(BackupNodeProtocol.class,
-            BackupNodeProtocol.versionID, bnAddress, new HdfsConfiguration());
+        RPC.getProxy(JournalProtocol.class,
+            JournalProtocol.versionID, bnAddress, new HdfsConfiguration());
     } catch(IOException e) {
       Storage.LOG.error("Error connecting to: " + bnAddress, e);
       throw e;

hdfs/src/java/org/apache/hadoop/hdfs/server/protocol/BackupNodeProtocol.java → hdfs/src/java/org/apache/hadoop/hdfs/server/protocol/JournalProtocol.java

@@ -24,11 +24,15 @@ import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.ipc.VersionedProtocol;
 import org.apache.hadoop.security.KerberosInfo;
 
+/**
+ * Protocol used to journal edits to a remote node. Currently,
+ * this is used to publish edits from the NameNode to a BackupNode.
+ */
 @KerberosInfo(
     serverPrincipal = DFSConfigKeys.DFS_NAMENODE_USER_NAME_KEY,
     clientPrincipal = DFSConfigKeys.DFS_NAMENODE_USER_NAME_KEY)
 @InterfaceAudience.Private
-public interface BackupNodeProtocol extends VersionedProtocol {
+public interface JournalProtocol extends VersionedProtocol {
   public static final long versionID = 1L;
 
   /**