org.apache.gora.cassandra.store

Class CassandraClient<K,T extends PersistentBase>

java.lang.Object

org.apache.gora.cassandra.store.CassandraClient<K,T>

Type Parameters:

K -

T -

public class CassandraClient<K,T extends PersistentBase>
extends Object

CassandraClient is where all of the primary datastore functionality is executed. Typically CassandraClient is invoked by calling CassandraStore.initialize(Class, Class, Properties). CassandraClient deals with Cassandra data model definition, mutation, and general/specific mappings.

See Also:

org.apache.gora.cassandra.store.CassandraStore#initialize(Class, Class, Properties)}

Field Summary

Fields

Modifier and Type	Field and Description
static String	DEFAULT_HECTOR_CONSIS_LEVEL Hector client default column family consistency level.
static org.slf4j.Logger	LOG The logging implementation

Constructor Summary

Constructors

Constructor and Description
CassandraClient()

Method Summary

Methods

Modifier and Type	Method and Description
void	addColumn(K key, String fieldName, Object value) Insert a field in a column.
void	addGenericArray(K key, String fieldName, org.apache.avro.generic.GenericArray<?> array)
void	addStatefulHashMap(K key, String fieldName, Map<CharSequence,Object> map)
void	addSubColumn(K key, String fieldName, ByteBuffer columnName, Object value) Insert a member in a super column.
void	addSubColumn(K key, String fieldName, Integer columnName, Object value) Adds an subColumn inside the cassandraMapping file when an Integer is serialized
void	addSubColumn(K key, String fieldName, String columnName, Object value) Adds an subColumn inside the cassandraMapping file when a String is serialized
void	checkKeyspace() Check if keyspace already exists.
void	deleteByKey(K key) Deletes an entry based on its key.
void	deleteColumn(K key, String familyName, ByteBuffer columnName) Delete a row within the keyspace.
void	deleteGenericArray(K key, String fieldName)
void	deleteStatefulHashMap(K key, String fieldName)
void	deleteSubColumn(K key, String fieldName) Deletes all subcolumns from a super column.
void	deleteSubColumn(K key, String fieldName, ByteBuffer columnName) Delete a member in a super column.
void	deleteSubColumn(K key, String fieldName, String columnName) Deletes a subColumn
void	dropKeyspace() Drop keyspace.
List<me.prettyprint.hector.api.beans.Row<K,ByteBuffer,ByteBuffer>>	execute(CassandraQuery<K,T> cassandraQuery, String family) Select a family column in the keyspace.
List<me.prettyprint.hector.api.beans.SuperRow<K,String,ByteBuffer,ByteBuffer>>	executeSuper(CassandraQuery<K,T> cassandraQuery, String family)
CassandraMapping	getCassandraMapping() Retrieves the cassandraMapping which holds whatever was mapped from the gora-cassandra-mapping.xml
Map<String,List<String>>	getFamilyMap(Query<K,T> query) Select the families that contain at least one column mapped to a query field.
String	getKeyspaceName() Obtain Schema/Keyspace name
Map<String,String>	getReverseMap(Query<K,T> query) Select the field names according to the column names, which format if fully qualified: "family:column"
void	initialize(Class<K> keyClass, Class<T> persistentClass) Method to maintain backward compatibility with earlier versions.
void	initialize(Class<K> keyClass, Class<T> persistentClass, Properties properties) Given our key, persistentClass from CassandraStore.initialize(Class, Class, Properties) we make best efforts to dictate our data model.
boolean	isSuper(String family) Determines if a column is a superColumn or not.
boolean	keyspaceExists() Check if keyspace already exists.
ByteBuffer	toByteBuffer(Object value) Serialize value to ByteBuffer using GoraSerializerTypeInferer.getSerializer(Object).

Methods inherited from class java.lang.Object

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

Field Detail

LOG

public static final org.slf4j.Logger LOG

The logging implementation

DEFAULT_HECTOR_CONSIS_LEVEL

public static final String DEFAULT_HECTOR_CONSIS_LEVEL

Hector client default column family consistency level.

See Also:

Constant Field Values

Constructor Detail

CassandraClient

public CassandraClient()

Method Detail

initialize

public void initialize(Class<K> keyClass,
              Class<T> persistentClass)
                throws Exception

Method to maintain backward compatibility with earlier versions.

Throws:

Exception

initialize

public void initialize(Class<K> keyClass,
              Class<T> persistentClass,
              Properties properties)
                throws Exception

Given our key, persistentClass from CassandraStore.initialize(Class, Class, Properties) we make best efforts to dictate our data model. We make a quick check within org.apache.gora.cassandra.store.CassandraClient#checkKeyspace(String) to see if our keyspace has already been invented, this simple check prevents us from recreating the keyspace if it already exists. We then simple specify (based on the input keyclass) an appropriate serializer via {@link org.apache.gora.cassandra.serializers.GoraSerializerTypeInferer} before defining a mutator from and by which we can mutate this object.

Parameters:

keyClass - the Key by which we wish o assign a record object

persistentClass - the generated org.apache.org.gora.persistency.Peristent bean representing the data.

properties - key value pairs from gora.properties

Throws:

Exception

keyspaceExists

public boolean keyspaceExists()

Check if keyspace already exists.

checkKeyspace

public void checkKeyspace()

Check if keyspace already exists. If not, create it. In this method, we also utilize Hector's ConfigurableConsistencyLevel logic. It is set by passing a ConfigurableConsistencyLevel object right when the Keyspace is created. If we cannot find a consistency level within gora.properites, then column family consistency level is set to QUORUM (by default) which permits consistency to wait for a quorum of replicas to respond regardless of data center. QUORUM is Hector Client's default setting and we respect that here as well.

See Also:

http://hector-client.github.io/hector/build/html/content/consistency_level.html

dropKeyspace

public void dropKeyspace()

Drop keyspace.

addColumn

public void addColumn(K key,
             String fieldName,
             Object value)

Insert a field in a column.

Parameters:

key - the row key

fieldName - the field name

value - the field value.

deleteColumn

public void deleteColumn(K key,
                String familyName,
                ByteBuffer columnName)

Delete a row within the keyspace.

Parameters:

key -

fieldName -

columnName -

deleteByKey

public void deleteByKey(K key)

Deletes an entry based on its key.

Parameters:

key -

addSubColumn

public void addSubColumn(K key,
                String fieldName,
                ByteBuffer columnName,
                Object value)

Insert a member in a super column. This is used for map and record Avro types.

Parameters:

key - the row key

fieldName - the field name

columnName - the column name (the member name, or the index of array)

value - the member value

addSubColumn

public void addSubColumn(K key,
                String fieldName,
                String columnName,
                Object value)

Adds an subColumn inside the cassandraMapping file when a String is serialized

Parameters:

key - the row key

fieldName - the field name

columnName - the column name (the member name, or the index of array)

value - the member value

addSubColumn

public void addSubColumn(K key,
                String fieldName,
                Integer columnName,
                Object value)

Adds an subColumn inside the cassandraMapping file when an Integer is serialized

Parameters:

key - the row key

fieldName - the field name

columnName - the column name (the member name, or the index of array)

value - the member value

deleteSubColumn

public void deleteSubColumn(K key,
                   String fieldName,
                   ByteBuffer columnName)

Delete a member in a super column. This is used for map and record Avro types.

Parameters:

key - the row key

fieldName - the field name

columnName - the column name (the member name, or the index of array)

deleteSubColumn

public void deleteSubColumn(K key,
                   String fieldName,
                   String columnName)

Deletes a subColumn

Parameters:

key -

fieldName -

columnName -

deleteSubColumn

public void deleteSubColumn(K key,
                   String fieldName)

Deletes all subcolumns from a super column.

Parameters:

key - the row key.

fieldName - the field name.

deleteGenericArray

public void deleteGenericArray(K key,
                      String fieldName)

addGenericArray

public void addGenericArray(K key,
                   String fieldName,
                   org.apache.avro.generic.GenericArray<?> array)

deleteStatefulHashMap

public void deleteStatefulHashMap(K key,
                         String fieldName)

addStatefulHashMap

public void addStatefulHashMap(K key,
                      String fieldName,
                      Map<CharSequence,Object> map)

toByteBuffer

public ByteBuffer toByteBuffer(Object value)

Serialize value to ByteBuffer using GoraSerializerTypeInferer.getSerializer(Object).

Parameters:

value - the member value Object.

Returns:

ByteBuffer object

execute

public List<me.prettyprint.hector.api.beans.Row<K,ByteBuffer,ByteBuffer>> execute(CassandraQuery<K,T> cassandraQuery,
                                                                         String family)

Select a family column in the keyspace.

Parameters:

cassandraQuery - a wrapper of the query

family - the family name to be queried

Returns:

a list of family rows

getFamilyMap

public Map<String,List<String>> getFamilyMap(Query<K,T> query)

Select the families that contain at least one column mapped to a query field.

Parameters:

query - indicates the columns to select

Returns:

a map which keys are the family names and values the corresponding column names required to get all the query fields.

getCassandraMapping

public CassandraMapping getCassandraMapping()

Retrieves the cassandraMapping which holds whatever was mapped from the gora-cassandra-mapping.xml

Returns:

getReverseMap

public Map<String,String> getReverseMap(Query<K,T> query)

Select the field names according to the column names, which format if fully qualified: "family:column"

Parameters:

query -

Returns:

a map which keys are the fully qualified column names and values the query fields

isSuper

public boolean isSuper(String family)

Determines if a column is a superColumn or not.

Parameters:

family -

Returns:

boolean

executeSuper

public List<me.prettyprint.hector.api.beans.SuperRow<K,String,ByteBuffer,ByteBuffer>> executeSuper(CassandraQuery<K,T> cassandraQuery,
                                                                                          String family)

getKeyspaceName

public String getKeyspaceName()

Obtain Schema/Keyspace name

Returns:

Keyspace