com.buabook.kdb.data

Class KdbTable

java.lang.Object

com.buabook.kdb.data.KdbTable

All Implemented Interfaces:

Iterable<KdbDict>

public class KdbTable
extends Object
implements Iterable<KdbDict>

Table Data Container for kdb

Data container representing a table that can be serialised and sent to a kdb process (via c)

Also provides the ability to accept a c.Flip object received from a kdb process and access it within Java, including iterating over it with the KdbDict object.

Implementation is not thread-safe.

(c) 2014 - 2017 Sport Trades Ltd

Since:

1 Apr 2014

Version:

1.1.0

Author:

Jas Rajasansir

See Also:

KdbTableIterator, KdbDict

Field Summary

Fields

Modifier and Type	Field and Description
private Map<String,List<Object>>	data The container of the kdb data stored column-wise
private static org.slf4j.Logger	log
private Integer	rowCount
private String	tableName The table name for the current instance

Constructor Summary

Constructors

Constructor and Description
KdbTable(String tableName) Instantiate an empty table structure
KdbTable(String tableName, c.Flip initialData) Instantiates a new kdb table object with a set of initial data in kdb format

Method Summary

Modifier and Type	Method and Description
void	addColumn(String columnName, List<Object> columnData) Adds a new column to the current table stored within the object.
void	addRow(KdbDict row)
void	addRow(Map<String,Object> row) Adds a row to a table based on an HashMap representation of the row (i.e.
void	append(KdbTable that) Appends the specified table onto the current table (similar to the kdb+ uj function)
static KdbTable	buildFromRowList(String name, List<KdbDict> rows) Accepts a list of KdbDict objects and generates a new KdbTable from it
void	changeTableName(String newTableName) Allows the name of the table stored within this object to be changed.
c.Flip	convertToFlip() Converts the nice Java representation of a kdb table into the actual format ready for sending across the wire to a kdb process.
void	deleteColumn(String columnName)
private void	doSetOfInitialDataSet(c.Flip initialData, boolean overwrite)
void	forceSetInitialDataSet(c.Flip initialData) Performs the initial (or subsequent) set of data from a kdb c.Flip object
static KdbTable	fromObject(Object object) Generates a new KdbTable object from an object.
KdbDict	getRow(int rowNumber) Provides the ability to return a specified row of the table.
Integer	getRowCount()
Map<String,List<Object>>	getTableData()
String	getTableName()
Boolean	isEmpty()
Iterator<KdbDict>	iterator()
void	setInitialDataSet(c.Flip initialData) Performs the initial set of data from a kdb c.Flip object
Stream<KdbDict>	stream() TODO: Implement Collection interface so this is an override

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Field Detail

log

private static final org.slf4j.Logger log

tableName

private String tableName

The table name for the current instance

data

private final Map<String,List<Object>> data

The container of the kdb data stored column-wise

rowCount

private Integer rowCount

Constructor Detail

KdbTable

public KdbTable(String tableName)
         throws IllegalArgumentException

Instantiate an empty table structure

Parameters:

tableName - The name of the table to create

Throws:

IllegalArgumentException - If the table name is empty or null

KdbTable

public KdbTable(String tableName,
                c.Flip initialData)
         throws DataOverwriteNotPermittedException

Instantiates a new kdb table object with a set of initial data in kdb format

Parameters:

tableName - The name of the table to create

initialData - The initial data set to populate the new object with

Throws:

IllegalArgumentException - If the table name is empty or null

DataOverwriteNotPermittedException

See Also:

#setInitialDataSet(Flip)

Method Detail

setInitialDataSet

public void setInitialDataSet(c.Flip initialData)
                       throws DataOverwriteNotPermittedException

Performs the initial set of data from a kdb c.Flip object

Parameters:

initialData - The dataset to use to set the object

Throws:

DataOverwriteNotPermittedException - If there is already data in the current data structure

See Also:

#doSetOfInitialDataSet(Flip, boolean)

forceSetInitialDataSet

public void forceSetInitialDataSet(c.Flip initialData)

Performs the initial (or subsequent) set of data from a kdb c.Flip object

Parameters:

initialData - The dataset to use to set the object

See Also:

#doSetOfInitialDataSet(Flip, boolean)

doSetOfInitialDataSet

private void doSetOfInitialDataSet(c.Flip initialData,
                                   boolean overwrite)
                            throws DataOverwriteNotPermittedException

Throws:

DataOverwriteNotPermittedException

addColumn

public void addColumn(String columnName,
                      List<Object> columnData)
               throws TableColumnAlreadyExistsException,
                      TableSchemaMismatchException

Adds a new column to the current table stored within the object.

Parameters:

columnName - The name of the new column

columnData - The list of new elements of the column

Throws:

TableColumnAlreadyExistsException - If there is a column with the same name as the one to be added

TableSchemaMismatchException - If the length of the new column does not match the current number of rows in the table

deleteColumn

public void deleteColumn(String columnName)

addRow

public void addRow(KdbDict row)
            throws TableSchemaMismatchException

Throws:

TableSchemaMismatchException

See Also:

addRow(Map)

addRow

public void addRow(Map<String,Object> row)
            throws TableSchemaMismatchException

Adds a row to a table based on an HashMap representation of the row (i.e. a kdb dictionary)

Parameters:

row - The new row to add

Throws:

TableSchemaMismatchException - If there are any missing columns from the new row

append

public void append(KdbTable that)
            throws TableSchemaMismatchException

Appends the specified table onto the current table (similar to the kdb+ uj function)

Throws:

TableSchemaMismatchException - If the two table names or table schemas do not match

getTableName

public String getTableName()

getTableData

public Map<String,List<Object>> getTableData()

convertToFlip

public c.Flip convertToFlip()

Converts the nice Java representation of a kdb table into the actual format ready for sending across the wire to a kdb process. NOTE: The columns of the generated table will always be in alphabetical order.

Returns:

The object that can be sent to a kdb process

getRowCount

public Integer getRowCount()

isEmpty

public Boolean isEmpty()

changeTableName

public void changeTableName(String newTableName)
                     throws UnsupportedOperationException

Allows the name of the table stored within this object to be changed.

Parameters:

newTableName - The new table name

Throws:

UnsupportedOperationException - If the new table name is null or an empty string

getRow

public KdbDict getRow(int rowNumber)
               throws ArrayIndexOutOfBoundsException

Provides the ability to return a specified row of the table. The row is provided as a KdbDict.

Parameters:

rowNumber - The row to retrieve

Returns:

The row

Throws:

ArrayIndexOutOfBoundsException - If the row requested is less than 0 or greater than or equal to the number of rows in the table

buildFromRowList

public static KdbTable buildFromRowList(String name,
                                        List<KdbDict> rows)
                                 throws TableSchemaMismatchException

Accepts a list of KdbDict objects and generates a new KdbTable from it

Parameters:

name - The name of the new table

rows - The list of rows to generate the table from

Returns:

The new table

Throws:

TableSchemaMismatchException

See Also:

addRow(KdbDict)

fromObject

public static KdbTable fromObject(Object object)
                           throws ClassCastException

Generates a new KdbTable object from an object. This method will only succeed if the object provided can be cast into a c.Flip.

Use this method along with KdbQuery to convert a query result into a table when one is expected.

Parameters:

object - The object to generate a new KdbTable from

Returns:

A new table or null if the provided object is null

Throws:

ClassCastException - If the specified object cannot be cast into a c.Flip

iterator

public Iterator<KdbDict> iterator()

Specified by:

iterator in interface Iterable<KdbDict>

stream

public Stream<KdbDict> stream()

TODO: Implement Collection interface so this is an override