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public interface ColumnTracker
Implementing classes of this interface will be used for the tracking and enforcement of columns and numbers of versions during the course of a Get or Scan operation.
Currently there are two different types of Store/Family-level queries.
ExplicitColumnTracker
is used when the query specifies
one or more column qualifiers to return in the family.
This class is utilized by ScanQueryMatcher
through two methods:
checkColumn(byte[], int, int, long)
is called when a Put satisfies all other
conditions of the query. This method returns a ScanQueryMatcher.MatchCode
to define
what action should be taken.
update()
is called at the end of every StoreFile or memstore.
This class is NOT thread-safe as queries are never multi-threaded
Method Summary | |
---|---|
ScanQueryMatcher.MatchCode |
checkColumn(byte[] bytes,
int offset,
int length,
long timestamp)
Keeps track of the number of versions for the columns asked for |
boolean |
done()
|
ColumnCount |
getColumnHint()
Used by matcher and scan/get to get a hint of the next column to seek to after checkColumn() returns SKIP. |
void |
reset()
Resets the Matcher |
void |
update()
Updates internal variables in between files |
Method Detail |
---|
ScanQueryMatcher.MatchCode checkColumn(byte[] bytes, int offset, int length, long timestamp)
bytes
- offset
- length
- timestamp
-
void update()
void reset()
boolean done()
true
when done.ColumnCount getColumnHint()
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