[jira] [Created] (HDFS-5285) Flatten INodeFile hierarchy

["Tsz Wo (Nicholas), SZE (JIRA)" <ji...@apache.org>]

Tsz Wo (Nicholas), SZE created HDFS-5285:
--------------------------------------------

             Summary: Flatten INodeFile hierarchy
                 Key: HDFS-5285
                 URL: https://issues.apache.org/jira/browse/HDFS-5285
             Project: Hadoop HDFS
          Issue Type: Sub-task
          Components: namenode
            Reporter: Tsz Wo (Nicholas), SZE
            Assignee: Tsz Wo (Nicholas), SZE


For files, there are INodeFile, INodeFileUnderConstruction, INodeFileWithSnapshot and INodeFileUnderConstructionWithSnapshot for representing whether a file is under construction or whether it is in some snapshot.  The following are two major problems of the current approach:
- Java class does not support multiple inheritances so that INodeFileUnderConstructionWithSnapshot cannot extend both INodeFileUnderConstruction and INodeFileWithSnapshot.
- The number of classes is exponential to the number of features.  Currently, there are only two features, UnderConstruction and WithSnapshot.  The number of classes is 2^2 = 4.  It is hard to add one more feature since the number of classes will become 2^3 = 8.



--
This message was sent by Atlassian JIRA
(v6.1#6144)