com.thinkaurelius.titan.diskstorage.keycolumnvalue

Class KCVSUtil

java.lang.Object

com.thinkaurelius.titan.diskstorage.keycolumnvalue.KCVSUtil

public class KCVSUtil
extends Object

Contains static utility methods for operating on KeyColumnValueStore.

Author:

Matthias Broecheler (me@matthiasb.com)

Constructor Summary

Constructors

Constructor and Description
KCVSUtil()

Method Summary

Methods

Modifier and Type	Method and Description
static boolean	containsKey(KeyColumnValueStore store, StaticBuffer key, int maxColumnLength, StoreTransaction txh)
static boolean	containsKey(KeyColumnValueStore store, StaticBuffer key, StoreTransaction txh)
static boolean	containsKeyColumn(KeyColumnValueStore store, StaticBuffer key, StaticBuffer column, StoreTransaction txh) Returns true if the specified key-column pair exists in the store.
static Map<StaticBuffer,EntryList>	emptyResults(List<StaticBuffer> keys)
static StaticBuffer	get(KeyColumnValueStore store, StaticBuffer key, StaticBuffer column, StoreTransaction txh) Retrieves the value for the specified column and key under the given transaction from the store if such exists, otherwise returns NULL
static KeyIterator	getKeys(KeyColumnValueStore store, StoreFeatures features, int keyLength, int sliceLength, StoreTransaction txh) If the store supports unordered scans, then call {#link KeyColumnValueStore.getKeys(SliceQuery, StoreTransaction).
static boolean	matches(KeyRangeQuery query, StaticBuffer key, StaticBuffer column)
static boolean	matches(SliceQuery query, StaticBuffer column)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

KCVSUtil

public KCVSUtil()

Method Detail

get

public static StaticBuffer get(KeyColumnValueStore store,
               StaticBuffer key,
               StaticBuffer column,
               StoreTransaction txh)
                        throws StorageException

Retrieves the value for the specified column and key under the given transaction from the store if such exists, otherwise returns NULL

Parameters:

store - Store

key - Key

column - Column

txh - Transaction

Returns:

Value for key and column or NULL if such does not exist

Throws:

StorageException

getKeys

public static KeyIterator getKeys(KeyColumnValueStore store,
                  StoreFeatures features,
                  int keyLength,
                  int sliceLength,
                  StoreTransaction txh)
                           throws StorageException

If the store supports unordered scans, then call {#link KeyColumnValueStore.getKeys(SliceQuery, StoreTransaction). The SliceQuery bounds are a binary all-zeros with an all-ones buffer. The limit is 1.

If the store supports ordered scans, then call {#link KeyColumnValueStore.getKeys(KeyRangeQuery, StoreTransaction). The key and columns slice bounds are the same as those described above. The column limit is 1.

Parameters:

store - the store to query

features - the store's features

keyLength - length of the zero/one buffers that form the key limits

sliceLength - length of the zero/one buffers that form the col limits

txh - transaction to use with getKeys

Returns:

keys returned by the store.getKeys call

Throws:

StorageException - unexpected failure

containsKeyColumn

public static boolean containsKeyColumn(KeyColumnValueStore store,
                        StaticBuffer key,
                        StaticBuffer column,
                        StoreTransaction txh)
                                 throws StorageException

Returns true if the specified key-column pair exists in the store.

Parameters:

store - Store

key - Key

column - Column

txh - Transaction

Returns:

TRUE, if key has at least one column-value pair, else FALSE

Throws:

StorageException

containsKey

public static boolean containsKey(KeyColumnValueStore store,
                  StaticBuffer key,
                  StoreTransaction txh)
                           throws StorageException

Throws:

StorageException

containsKey

public static boolean containsKey(KeyColumnValueStore store,
                  StaticBuffer key,
                  int maxColumnLength,
                  StoreTransaction txh)
                           throws StorageException

Throws:

StorageException

matches

public static boolean matches(SliceQuery query,
              StaticBuffer column)

matches

public static boolean matches(KeyRangeQuery query,
              StaticBuffer key,
              StaticBuffer column)

emptyResults

public static Map<StaticBuffer,EntryList> emptyResults(List<StaticBuffer> keys)