Space: The abstract space. More...

#include <space.h>

Inheritance diagram for jazz_bebop::Space:

Public Member Functions
	Space (pBaseAPI api, pName a_name)
	Bop: Create the Space.

virtual StatusCode	start ()

virtual StatusCode	shut_down ()

virtual StatusCode	load_meta ()
	Load the metadata of the Space.

virtual StatusCode	save_meta ()
	Save the metadata of the Space.

virtual RowNumber	num_rows ()
	Return the number of rows in the Space.

virtual void *	get_index_data (RowNumber row)
	Get a pointer to the data of the index of a given row.

virtual int	num_cols ()
	Get the number of columns in the Space.

virtual pName	col_name (int col)
	Get the name of a column.

virtual int	col_index (pName name)
	Get the index of a column.

virtual pLocator	locator (RowNumber row, int col, int &index)
	Get the location of a cell as a Locator.

virtual pRowSelection	where (pChar query)
	Get a RowSelection from a query.

virtual pColSelection	select (pChar query)
	Get a ColSelection from a query.

virtual pCaster	as (pChar query)
	Get the appropriate Caster from the AS clause of a query.

virtual bool	register_caster (pCaster cast)
	Register a Caster descendant to make it available in queries.

virtual StatusCode	get_row (pTransaction &p_txn, RowNumber row, pColSelection cols=nullptr, pCaster cast=nullptr)
	Get a row from the Space as a Tuple.

Public Member Functions inherited from jazz_elements::Service
	Service (pLogger a_logger, pConfigFile a_config)

virtual pChar const	id ()

void	log (int loglevel, const char *message)

void	log_printf (int loglevel, const char *fmt,...)

bool	get_conf_key (const char *key, int &value)

bool	get_conf_key (const char *key, double &value)

bool	get_conf_key (const char *key, std::string &value)

Protected Attributes
char	storage_base [SHORT_NAME_SIZE]
	The base name of the storage container.

Name	name
	The name of the Space.

pBaseAPI	p_api
	A pointer to the BaseAPI that provides access to containers.

Casters	casters
	A map of all the available Casters.

Additional Inherited Members
Data Fields inherited from jazz_elements::Service
pLogger	p_log
	The logger.

pConfigFile	p_conf
	The configuration file.

Detailed Description

Space: The abstract space.

This is the abstract parent of DataSpaces, Fields/SemSpaces and Snippet/Concept. A Space is an abstraction over many blocks that provides:

An abstraction in the form of rows and columns.
A mechanism to load and update its own metadata in a persisted way.

Through inheritance, it provides su things as:

Sharding and replication across a cluster.
A mechanism to load, update, invalidate blocks. This supports continuous update like in time series.
Indexing by time, key, embedding, etc.

The class Space is mostly empty. It provides the parent virtual interface and the parents of all the auxiliary classes used to access data.

See also: DataSpaces, Fields, jazz_models::SemSpaces, Snippet, jazz_models::Concept

Constructor & Destructor Documentation

◆ Space()

jazz_bebop::Space::Space	(	pBaseAPI	api,
		pName	a_name
	)

Bop: Create the Space.

Parameters

api	A pointer to a BaseAPI that provides access to containers.
a_name	The name of the Space.

Member Function Documentation

◆ start()

StatusCode jazz_bebop::Space::start ( )

virtual

Starts the Space service

Returns: SERVICE_NO_ERROR if successful, an error code otherwise.

Reimplemented from jazz_elements::Service.

Reimplemented in jazz_models::SemSpace.

◆ shut_down()

StatusCode jazz_bebop::Space::shut_down ( )

virtual

Shuts down the Space Service

Returns: SERVICE_NO_ERROR if successful, an error code otherwise.

Reimplemented from jazz_elements::Service.

◆ load_meta()

virtual StatusCode jazz_bebop::Space::load_meta ( )

inlinevirtual

Load the metadata of the Space.

This method must be implemented by descendants. It will load a record of metadata from //storage_base/storage_ent/name.

Returns: SERVICE_NO_ERROR if successful, an error code otherwise.

◆ save_meta()

virtual StatusCode jazz_bebop::Space::save_meta ( )

inlinevirtual

Save the metadata of the Space.

This method must be implemented by descendants. It will store a record of metadata into //storage_base/storage_ent/name.

Returns: SERVICE_NO_ERROR if successful, an error code otherwise.

◆ num_rows()

virtual RowNumber jazz_bebop::Space::num_rows ( )

inlinevirtual

Return the number of rows in the Space.

Returns: The number of rows in the Space or SPACE_NOT_A_ROW if the Space is invalid.

◆ get_index_data()

virtual void * jazz_bebop::Space::get_index_data ( RowNumber row )

inlinevirtual

Get a pointer to the data of the index of a given row.

Parameters

row	The row number.

Returns: A pointer to the index or nullptr if there is no index. Examples include a vector for an embedding, of a string for a key-based index and a TimePoint for a time-based index.

◆ num_cols()

virtual int jazz_bebop::Space::num_cols ( )

inlinevirtual

Get the number of columns in the Space.

Returns: The number of columns in the Space.

◆ col_name()

virtual pName jazz_bebop::Space::col_name ( int col )

inlinevirtual

Get the name of a column.

Parameters

col	The column index.

Returns: The name of the column or nullptr if the index is out of range.

◆ col_index()

virtual int jazz_bebop::Space::col_index ( pName name )

inlinevirtual

Get the index of a column.

Parameters

name	The name of the column.

Returns: The index of the column or -1 if the column is not found.

◆ locator()

virtual pLocator jazz_bebop::Space::locator	(	RowNumber	row,
		int	col,
		int &	index
	)

inlinevirtual

Get the location of a cell as a Locator.

Parameters

row	The row number.
col	The column index.
index	If the block contains multiple rows, which is the index of `row` in the block.

Returns: A pointer to a Locator object that can be used to access the cell or nullptr if the cell is not found.

◆ where()

virtual pRowSelection jazz_bebop::Space::where ( pChar query )

inlinevirtual

Get a RowSelection from a query.

Parameters

query A query string that is understood by the descendant. In Bop, this is the content of a WHERE clause with a syntax that depends on how the Space is indexed (Time, categorical, Embedding storage, ...).

Returns: A RowSelection object that can be used to iterate over the rows that match the query.

◆ select()

virtual pColSelection jazz_bebop::Space::select ( pChar query )

inlinevirtual

Get a ColSelection from a query.

Parameters

query By default, a list of comma separated column names. Spaces that use descendants of ColSelection may define a different interface.

Returns: A ColSelection object that can be used to iterate over the selected columns. If the query is invalid, the object will be invalid and return no columns. This is intentional since nullptr in a get_row() call means "all columns". An invalid query produces a selection of "no columns".

◆ as()

virtual pCaster jazz_bebop::Space::as ( pChar query )

inlinevirtual

Get the appropriate Caster from the AS clause of a query.

Parameters

query The name of the Caster to get.

Returns: A pointer to the Caster or nullptr if the Caster is not found.

◆ register_caster()

virtual bool jazz_bebop::Space::register_caster ( pCaster cast )

inlinevirtual

Register a Caster descendant to make it available in queries.

Parameters

cast	The Caster to register.

Returns: True if the Caster was successfully registered, false if a Caster with the same name is already registered.

◆ get_row()

virtual StatusCode jazz_bebop::Space::get_row	(	pTransaction &	p_txn,
		RowNumber	row,
		pColSelection	cols = `nullptr`,
		pCaster	cast = `nullptr`
	)

inlinevirtual

Get a row from the Space as a Tuple.

Parameters

p_txn	A transaction that will be used to get the result. It must be destroyed with: p_txn->p_owner->destroy_transaction(p_txn)
row	The row number as obtained from a RowSelection.next() call.
cols	Pointer to a ColSelection to specify columns to be retrieved. If nullptr, all columns are retrieved.
cast	Pointer to a Caster to convert the result. If nullptr, no conversion is done.

Returns: SERVICE_NO_ERROR if successful, an error code otherwise.

The documentation for this class was generated from the following files:

space.h
space.cpp

Public Member Functions

Protected Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ Space()

Member Function Documentation

◆ start()

◆ shut_down()

◆ load_meta()

◆ save_meta()

◆ num_rows()

◆ get_index_data()

◆ num_cols()

◆ col_name()

◆ col_index()

◆ locator()

◆ where()

◆ select()

◆ as()

◆ register_caster()

◆ get_row()