org.apache.gora.mongodb.store

Class MongoStore<K,T extends PersistentBase>

java.lang.Object

org.apache.gora.store.impl.DataStoreBase<K,T>

org.apache.gora.mongodb.store.MongoStore<K,T>

Type Parameters:

K - class to be used for the key

T - class to be persisted within the store

All Implemented Interfaces:

Closeable, AutoCloseable, DataStore<K,T>, org.apache.hadoop.conf.Configurable, org.apache.hadoop.io.Writable

public class MongoStore<K,T extends PersistentBase>
extends DataStoreBase<K,T>

Implementation of a MongoDB data store to be used by gora.

Author:

Fabien Poulard , Damien Raude-Morvan

Field Summary

Fields

Modifier and Type	Field and Description
static String	DEFAULT_MAPPING_FILE Default value for mapping file
static org.slf4j.Logger	LOG
static String	PROP_MAPPING_FILE Property pointing to the file for the mapping
static String	PROP_MONGO_DB Property to select the database
static String	PROP_MONGO_LOGIN Property pointing to the username to connect to the server
static String	PROP_MONGO_SECRET Property pointing to the secret to connect to the server
static String	PROP_MONGO_SERVERS Property pointing to the host where the server is running
static String	PROP_OVERRIDING Property indicating if the hadoop configuration has priority or not

Fields inherited from class org.apache.gora.store.impl.DataStoreBase

autoCreateSchema, beanFactory, conf, datumReader, datumWriter, fieldMap, keyClass, persistentClass, properties, schema

Constructor Summary

Constructors

Constructor and Description
MongoStore()

Method Summary

Methods

Modifier and Type	Method and Description
void	close() Release the resources linked to this collection
void	createSchema() Create a new collection in MongoDB if necessary.
String	decodeFieldKey(String key) Ensure Key decoding -> middle dots replaced with dots
boolean	delete(K key) Deletes the object with the given key
long	deleteByQuery(Query<K,T> query) Deletes all the objects matching the query.
void	deleteSchema() Drop the collection.
String	encodeFieldKey(String key) Ensure Key encoding -> dots replaced with middle dots
Result<K,T>	execute(Query<K,T> query) Execute the query and return the result.
void	flush() Ensure the data is synced to disk.
T	get(K key, String[] fields) Retrieve an entry from the store with only selected fields.
MongoMapping	getMapping()
List<PartitionQuery<K,T>>	getPartitions(Query<K,T> query) Partitions the given query and returns a list of PartitionQuerys, which will execute on local data.
String	getSchemaName() Accessor to the name of the collection used.
String	getSchemaName(String mappingSchemaName, Class<?> persistentClass) Returns the name of the schema to use for the persistent class.
void	initialize(Class<K> keyClass, Class<T> pPersistentClass, Properties properties) Initialize the data store by reading the credentials, setting the client's properties up and reading the mapping file.
T	newInstance(com.mongodb.DBObject obj, String[] fields) Build a new instance of the persisted class from the DBObject retrieved from the database.
Query<K,T>	newQuery() Create a new Query to query the datastore.
void	put(K key, T obj) Persist an object into the store.
boolean	schemaExists() Check if the collection already exists or should be created.

Methods inherited from class org.apache.gora.store.impl.DataStoreBase

equals, get, getBeanFactory, getConf, getFields, getFieldsToQuery, getKeyClass, getOrCreateConf, getPersistentClass, newKey, newPersistent, readFields, setBeanFactory, setConf, setKeyClass, setPersistentClass, truncateSchema, write

Methods inherited from class java.lang.Object

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

Field Detail

LOG

public static final org.slf4j.Logger LOG

PROP_OVERRIDING

public static final String PROP_OVERRIDING

Property indicating if the hadoop configuration has priority or not

See Also:

Constant Field Values

PROP_MAPPING_FILE

public static final String PROP_MAPPING_FILE

Property pointing to the file for the mapping

See Also:

Constant Field Values

PROP_MONGO_SERVERS

public static final String PROP_MONGO_SERVERS

Property pointing to the host where the server is running

See Also:

Constant Field Values

PROP_MONGO_LOGIN

public static final String PROP_MONGO_LOGIN

Property pointing to the username to connect to the server

See Also:

Constant Field Values

PROP_MONGO_SECRET

public static final String PROP_MONGO_SECRET

Property pointing to the secret to connect to the server

See Also:

Constant Field Values

DEFAULT_MAPPING_FILE

public static final String DEFAULT_MAPPING_FILE

Default value for mapping file

See Also:

Constant Field Values

PROP_MONGO_DB

public static String PROP_MONGO_DB

Property to select the database

Constructor Detail

MongoStore

public MongoStore()

Method Detail

initialize

public void initialize(Class<K> keyClass,
              Class<T> pPersistentClass,
              Properties properties)

Initialize the data store by reading the credentials, setting the client's properties up and reading the mapping file.

Specified by:

initialize in interface DataStore<K,T extends PersistentBase>

Overrides:

initialize in class DataStoreBase<K,T extends PersistentBase>

Parameters:

keyClass - the class of the keys

pPersistentClass - the class of the persistent objects

properties - extra metadata

getMapping

public MongoMapping getMapping()

getSchemaName

public String getSchemaName()

Accessor to the name of the collection used.

Returns:

schema name

getSchemaName

public String getSchemaName(String mappingSchemaName,
                   Class<?> persistentClass)

Description copied from class: DataStoreBase

Returns the name of the schema to use for the persistent class. First the schema name in the Configuration is used. If null, the schema name in the defined properties is returned. If null then the provided mappingSchemaName is returned. If this is null too, the class name, without the package, of the persistent class is returned.

Overrides:

getSchemaName in class DataStoreBase<K,T extends PersistentBase>

Parameters:

mappingSchemaName - the name of the schema as read from the mapping file

persistentClass - persistent class

createSchema

public void createSchema()

Create a new collection in MongoDB if necessary.

deleteSchema

public void deleteSchema()

Drop the collection.

schemaExists

public boolean schemaExists()

Check if the collection already exists or should be created.

Returns:

whether schema exists

flush

public void flush()

Ensure the data is synced to disk.

close

public void close()

Release the resources linked to this collection

get

public T get(K key,
    String[] fields)

Retrieve an entry from the store with only selected fields.

Parameters:

key - identifier of the document in the database

fields - list of fields to be loaded from the database

Returns:

the Object corresponding to the key or null if it cannot be found

Throws:

IOException

put

public void put(K key,
       T obj)

Persist an object into the store.

Parameters:

key - identifier of the object in the store

obj - the object to be inserted

delete

public boolean delete(K key)

Description copied from interface: DataStore

Deletes the object with the given key

Parameters:

key - the key of the object

Returns:

whether the object was successfully deleted

deleteByQuery

public long deleteByQuery(Query<K,T> query)

Description copied from interface: DataStore

Deletes all the objects matching the query. See also the note on visibility.

Parameters:

query - matching records to this query will be deleted

Returns:

number of deleted records

execute

public Result<K,T> execute(Query<K,T> query)

Execute the query and return the result.

Parameters:

query - the query to execute.

Returns:

the results as a Result object.

newQuery

public Query<K,T> newQuery()

Create a new Query to query the datastore.

Returns:

a new Query.

getPartitions

public List<PartitionQuery<K,T>> getPartitions(Query<K,T> query)
                                                               throws IOException

Partitions the given query and returns a list of PartitionQuerys, which will execute on local data.

Parameters:

query - the base query to create the partitions for. If the query is null, then the data store returns the partitions for the default query (returning every object)

Returns:

a List of PartitionQuery's

Throws:

IOException

newInstance

public T newInstance(com.mongodb.DBObject obj,
            String[] fields)

Build a new instance of the persisted class from the DBObject retrieved from the database.

Parameters:

obj - the DBObject that results from the query to the database

fields - the list of fields to be mapped to the persistence class instance

Returns:

a persistence class instance which content was deserialized from the DBObject

Throws:

IOException

encodeFieldKey

public String encodeFieldKey(String key)

Ensure Key encoding -> dots replaced with middle dots

Parameters:

key - char with only dots.

Returns:

encoded string with "·" chars..

decodeFieldKey

public String decodeFieldKey(String key)

Ensure Key decoding -> middle dots replaced with dots

Parameters:

key - encoded string with "·" chars.

Returns:

Cleanup up char with only dots.