com.googlecode.n_orm.storeapi

Interface SimpleStore

All Known Implementing Classes:

Memory

public interface SimpleStore

An interface that defines what a data store should implement and which is simpler than Store. The expected data model is that one of column-oriented databases such as data models of BigTable, HBase or Cassandra. To summarize, a data store should provide a set of maps (we'll call tables). Each one of these tables is a map which contains rows that associate a String key with a set of column families. It should be easy and efficient to find a row in a table using its key, or defining a key with a minimum value and a maximum value as if key would be organized in a dictionary (see String.compareTo(String)). Each column family is a map which associates a qualifier with data, represented by a byte array.

See Also:

a default implementation

Method Summary

Modifier and Type	Method and Description
long	count(String table, Constraint c) Counts the number of element satisfying the constraint.
void	delete(String table, String id) Deletes the given row
boolean	exists(String table, String row) Tests for a row.
boolean	exists(String table, String row, String family) Tests whether a column family is empty.
CloseableKeyIterator	get(String table, Constraint c, int limit, Set<String> families) Rows matching constraint sorted according to their key in ascending order.
Row.ColumnFamilyData	get(String table, String id, Set<String> families) Returns all elements in families ; no side-effect.
Map<String,byte[]>	get(String table, String id, String family) Returns all elements in a family ; no side-effect.
Map<String,byte[]>	get(String table, String id, String family, Constraint c) Returns all elements in a family ; no side-effect.
byte[]	get(String table, String row, String family, String key) Returns an element from a family.
boolean	hasTable(String tableName) Checks whether the given table exists in this store.
void	start() Called once the store is created ; only one store is instanciated with the same properties.
void	storeChanges(String table, String id, Row.ColumnFamilyData changed, Map<String,Set<String>> removed, Map<String,Map<String,Number>> increments) Stores given piece of information.

Method Detail

start

void start()
    throws DatabaseNotReachedException

Called once the store is created ; only one store is instanciated with the same properties.

Throws:

DatabaseNotReachedException

hasTable

boolean hasTable(String tableName)
          throws DatabaseNotReachedException

Checks whether the given table exists in this store.

Throws:

DatabaseNotReachedException

exists

boolean exists(String table,
               String row)
        throws DatabaseNotReachedException

Tests for a row.

Throws:

DatabaseNotReachedException

exists

boolean exists(String table,
               String row,
               String family)
        throws DatabaseNotReachedException

Tests whether a column family is empty.

Throws:

DatabaseNotReachedException

get

CloseableKeyIterator get(String table,
                         Constraint c,
                         int limit,
                         Set<String> families)
                  throws DatabaseNotReachedException

Rows matching constraint sorted according to their key in ascending order.

Parameters:

families - TODO

Throws:

DatabaseNotReachedException

get

byte[] get(String table,
           String row,
           String family,
           String key)
    throws DatabaseNotReachedException

Returns an element from a family.

Throws:

DatabaseNotReachedException

get

Map<String,byte[]> get(String table,
                       String id,
                       String family)
                throws DatabaseNotReachedException

Returns all elements in a family ; no side-effect. In case one element is missing, null is returned.

Throws:

DatabaseNotReachedException

get

Map<String,byte[]> get(String table,
                       String id,
                       String family,
                       Constraint c)
                throws DatabaseNotReachedException

Returns all elements in a family ; no side-effect. In case one element is missing, null is returned.

Throws:

DatabaseNotReachedException

get

Row.ColumnFamilyData get(String table,
                         String id,
                         Set<String> families)
                  throws DatabaseNotReachedException

Returns all elements in families ; no side-effect. In case element with the given key is missing, null is returned.

Parameters:

table - the table from which to find the element

id - the unique identifier (i.e. the key) with which the element was stored

families - the set of column families to be activated ; should never be null or empty

Returns:

the data stored for each family ; null if and only if the id does not exist in the table

Throws:

DatabaseNotReachedException

storeChanges

void storeChanges(String table,
                  String id,
                  Row.ColumnFamilyData changed,
                  Map<String,Set<String>> removed,
                  Map<String,Map<String,Number>> increments)
           throws DatabaseNotReachedException

Stores given piece of information. In case an element is missing in the data store (table, row, family, ...), it is created.

Throws:

DatabaseNotReachedException

delete

void delete(String table,
            String id)
     throws DatabaseNotReachedException

Deletes the given row

Throws:

DatabaseNotReachedException

count

long count(String table,
           Constraint c)
    throws DatabaseNotReachedException

Counts the number of element satisfying the constraint.

Throws:

DatabaseNotReachedException