[HBASE-20625] refactor some WALCellCodec related code

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 2.0.0
• Fix Version/s: 3.0.0-alpha-1, 2.1.0
• Component/s: wal
• Assignee: Jingyun Tian
• Reporter: Jingyun Tian
• Created: 23/May/18 09:27
• Updated: 13/Dec/18 16:23
• Resolved: 14/Jun/18 11:49

Description

Currently I'm working on export HLog to another FileSystem, then I found the code of WALCellCodec and its related classes is not that clean. And there are several TODOs. Thus I tried to refactor the code based one these TODOs. e.g.

  // TODO: it sucks that compression context is in WAL.Entry. It'd be nice if it was here.
  //       Dictionary could be gotten by enum; initially, based on enum, context would create
  //       an array of dictionaries.
  static class BaosAndCompressor extends ByteArrayOutputStream implements ByteStringCompressor {
    public ByteString toByteString() {
      // We need this copy to create the ByteString as the byte[] 'buf' is not immutable. We reuse
      // them.
      return ByteString.copyFrom(this.buf, 0, this.count);
    }

Issue Links

• links to: Review Board (master)