public interface KeyColumnValueStore
This interface provides methods for retrieving and mutating the data.
In this generic representation keys, columns and values are represented as ByteBuffers.
Modifier and Type | Field and Description |
---|---|
static List<Entry> |
NO_ADDITIONS |
static List<StaticBuffer> |
NO_DELETIONS |
Modifier and Type | Method and Description |
---|---|
void |
acquireLock(StaticBuffer key,
StaticBuffer column,
StaticBuffer expectedValue,
StoreTransaction txh)
Attempts to claim a lock on the value at the specified
key and
column pair. |
void |
close()
Closes this store
|
KeyIterator |
getKeys(KeyRangeQuery query,
StoreTransaction txh)
Returns a
KeyIterator over all keys that fall within the key-range specified by the given query and have one or more columns matching the column-range. |
KeySlicesIterator |
getKeys(MultiSlicesQuery queries,
StoreTransaction txh)
Returns a
KeySlicesIterator over all keys in the store that have one or more columns matching the column-range. |
KeyIterator |
getKeys(SliceQuery query,
StoreTransaction txh)
Returns a
KeyIterator over all keys in the store that have one or more columns matching the column-range. |
String |
getName()
Returns the name of this store.
|
EntryList |
getSlice(KeySliceQuery query,
StoreTransaction txh)
Retrieves the list of entries (i.e.
|
Map<StaticBuffer,EntryList> |
getSlice(List<StaticBuffer> keys,
SliceQuery query,
StoreTransaction txh)
Retrieves the list of entries (i.e.
|
void |
mutate(StaticBuffer key,
List<Entry> additions,
List<StaticBuffer> deletions,
StoreTransaction txh)
Verifies acquisition of locks
txh from previous calls to
acquireLock(StaticBuffer, StaticBuffer, StaticBuffer, StoreTransaction)
, then writes supplied additions and/or deletions to
key in the underlying data store. |
static final List<StaticBuffer> NO_DELETIONS
EntryList getSlice(KeySliceQuery query, StoreTransaction txh) throws BackendException
query
- Query to get results fortxh
- TransactionBackendException
- when columnEnd < columnStartKeySliceQuery
Map<StaticBuffer,EntryList> getSlice(List<StaticBuffer> keys, SliceQuery query, StoreTransaction txh) throws BackendException
SliceQuery
for all
of the given keys together.keys
- List of keysquery
- Slicequery specifying matching entriestxh
- TransactionBackendException
void mutate(StaticBuffer key, List<Entry> additions, List<StaticBuffer> deletions, StoreTransaction txh) throws BackendException
txh
from previous calls to
acquireLock(StaticBuffer, StaticBuffer, StaticBuffer, StoreTransaction)
, then writes supplied additions
and/or deletions
to
key
in the underlying data store. Deletions are applied strictly
before additions. In other words, if both an addition and deletion are
supplied for the same column, then the column will first be deleted and
then the supplied Entry for the column will be added.
Implementations which don't support locking should skip the initial lock verification step but otherwise behave as described above.
key
- the key under which the columns in additions
and
deletions
will be writtenadditions
- the list of Entry instances representing column-value pairs to
create under key
, or null to add no column-value pairsdeletions
- the list of columns to delete from key
, or null to
delete no columnstxh
- the transaction to usePermanentLockingException
- if locking is supported by the implementation and at least
one lock acquisition attempted by
acquireLock(StaticBuffer, StaticBuffer, StaticBuffer, StoreTransaction)
has failedBackendException
void acquireLock(StaticBuffer key, StaticBuffer column, StaticBuffer expectedValue, StoreTransaction txh) throws BackendException
key
and
column
pair. These locks are discretionary.
If locking fails, implementations of this method may, but are not
required to, throw PermanentLockingException
.
This method is not required
to determine whether locking actually succeeded and may return without
throwing an exception even when the lock can't be acquired. Lock
acquisition is only only guaranteed to be verified by the first call to
mutate(StaticBuffer, List, List, StoreTransaction)
on any given
txh
.
The expectedValue
must match the actual value present at the
key
and column
pair. If the true value does not match the
expectedValue
, the lock attempt fails and
LockingException
is thrown. This method may check
expectedValue
. The mutate()
mutate is required to check
it.
When this method is called multiple times on the same key
,
column
, and txh
, calls after the first have no effect.
Locks acquired by this method must be automatically released on
transaction commit()
or rollback()
.
Implementations which don't support locking should throw
UnsupportedOperationException
.
key
- the key on which to lockcolumn
- the column on which to lockexpectedValue
- the expected value for the specified key-column pair on which
to lock (null means the pair must have no value)txh
- the transaction to usePermanentLockingException
- the lock could not be acquired due to contention with other
transactions or a locking-specific storage problemBackendException
KeyIterator getKeys(KeyRangeQuery query, StoreTransaction txh) throws BackendException
KeyIterator
over all keys that fall within the key-range specified by the given query and have one or more columns matching the column-range.
Calling KeyIterator.getEntries()
returns the list of all entries that match the column-range specified by the given query.
This method is only supported by stores which keep keys in byte-order.
query
- txh
- BackendException
KeyIterator getKeys(SliceQuery query, StoreTransaction txh) throws BackendException
KeyIterator
over all keys in the store that have one or more columns matching the column-range. Calling KeyIterator.getEntries()
returns the list of all entries that match the column-range specified by the given query.
This method is only supported by stores which do not keep keys in byte-order.
query
- txh
- BackendException
KeySlicesIterator getKeys(MultiSlicesQuery queries, StoreTransaction txh) throws BackendException
KeySlicesIterator
over all keys in the store that have one or more columns matching the column-range. Calling KeySlicesIterator.getEntries()
returns the map of all entries that match the column-range specified by the given queries.
This method is mandatory for stores which do not guaranty key orders while running parallel scans.
queries
- txh
- BackendException
String getName()
KeyColumnValueStoreManager.openDatabase(String)
void close() throws BackendException
BackendException
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