public static long getTimestamp(String name) {
    Matcher matcher = WAL_FILE_NAME_PATTERN.matcher(name);
    return matcher.matches() ? Long.parseLong(matcher.group(2)) : NO_TIMESTAMP;
  }
Split a WAL filename to get a start time. WALs usually have the time we start writing to them
with as part of their name, usually the suffix. Sometimes there will be an extra suffix as when
it is a WAL for the meta table. For example, WALs might look like this
<code>10.20.20.171%3A60020.1277499063250</code> where <code>1277499063250</code> is the
timestamp. Could also be a meta WAL which adds a '.meta' suffix or a synchronous replication
WAL which adds a '.syncrep' suffix. Check for these. File also may have no timestamp on it. For
example the recovered.edits files are WALs but are named in ascending order. Here is an
example: 0000000000000016310. Allow for this.
@param name Name of the WAL file.
@return Timestamp or {@link #NO_TIMESTAMP}.
hbase-server/src/main/java/org/apache/hadoop/hbase/wal/AbstractFSWALProvider.java