com.buabook.kdb.consumer

Class KdbConsumer

java.lang.Object

com.buabook.kdb.connection.KdbConnection

com.buabook.kdb.consumer.KdbConsumer

All Implemented Interfaces:

AutoCloseable

public class KdbConsumer
extends KdbConnection

KDB Data Consumer

Provides the ability to consume real-time streaming data from a KDB process into a KdbTable for use within a Java application

(c) 2014 - 2015 Sport Trades Ltd

Since:

23 Apr 2014

Version:

1.1.0

Author:

Jas Rajasansir

Field Summary

Fields

Modifier and Type	Field and Description
private static org.slf4j.Logger	log
private IKdbRawDataConsumer	rawDataConsumer A listener object that will consume any valid message received from the kdb process
private static String	SUB_FUNCTION
private KdbDict	subscriptionConfiguration An optional dictionary of subscription information if the upstream kdb process supports subscription configuration
private List<String>	subscriptionTables The list of tables that this consumer will subscribe to
private static List<String>	SUPPORTED_UPD_FUNCTIONS
private IKdbTableConsumer	tableConsumer A listener object that will only consume table updates
private static Integer	UPD_ARRAY_LENGTH The length of the array returned by kdb in order for it to be considered as a valid update message

Fields inherited from class com.buabook.kdb.connection.KdbConnection

reconnectIntervalMs

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	KdbConsumer(KdbProcess server, KdbDict subscriptionConfiguration, IKdbRawDataConsumer rawDataConsumer, IKdbTableConsumer tableConsumer)
protected	KdbConsumer(KdbProcess server, List<String> tables, IKdbRawDataConsumer rawDataConsumer, IKdbTableConsumer tableConsumer) Generates a new kdb consumer (which is generally a consumer from a kdb TickerPlant)
	KdbConsumer(KdbProcess server, List<String> tables, IKdbTableConsumer tableConsumer)
private	KdbConsumer(KdbProcess server, List<String> tables, KdbDict subscriptionConfiguration, IKdbRawDataConsumer rawDataConsumer, IKdbTableConsumer tableConsumer)

Method Summary

Modifier and Type	Method and Description
private void	listen() Commences listening for messages to be sent to this consumer from the kdb process.
void	reconnect() Performs the reconnection logic as defined in the super class.
private Boolean	subscribe() Performs a subscription request to the kdb process (.u.sub) with the specified list of tables and symbols specified at object construction time
void	subscribeAndListen() Once connection to the process has been established (performed during object construction), then this function is called to first subscribe to the kdb TickerPlant and, if successful, start listening for update messages

Methods inherited from class com.buabook.kdb.connection.KdbConnection

close, connect, disconnect, getConnection, getRemoteProcess, isConnected

Methods inherited from class java.lang.Object

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

Field Detail

log

private static final org.slf4j.Logger log

SUPPORTED_UPD_FUNCTIONS

private static final List<String> SUPPORTED_UPD_FUNCTIONS

SUB_FUNCTION

private static final String SUB_FUNCTION

See Also:

Constant Field Values

UPD_ARRAY_LENGTH

private static final Integer UPD_ARRAY_LENGTH

The length of the array returned by kdb in order for it to be considered as a valid update message

subscriptionTables

private final List<String> subscriptionTables

The list of tables that this consumer will subscribe to

subscriptionConfiguration

private final KdbDict subscriptionConfiguration

An optional dictionary of subscription information if the upstream kdb process supports subscription configuration

rawDataConsumer

private final IKdbRawDataConsumer rawDataConsumer

A listener object that will consume any valid message received from the kdb process

tableConsumer

private final IKdbTableConsumer tableConsumer

A listener object that will only consume table updates

Constructor Detail

KdbConsumer

private KdbConsumer(KdbProcess server,
                    List<String> tables,
                    KdbDict subscriptionConfiguration,
                    IKdbRawDataConsumer rawDataConsumer,
                    IKdbTableConsumer tableConsumer)
             throws KdbTargetProcessUnavailableException

Throws:

KdbTargetProcessUnavailableException

KdbConsumer

protected KdbConsumer(KdbProcess server,
                      List<String> tables,
                      IKdbRawDataConsumer rawDataConsumer,
                      IKdbTableConsumer tableConsumer)
               throws KdbTargetProcessUnavailableException

Generates a new kdb consumer (which is generally a consumer from a kdb TickerPlant)

Parameters:

server - The kdb process to connect to

tables - The list of tables that should be subscribed to. NOTE: This cannot be null, pass an empty list

rawDataConsumer - A listener object that will consume every message from the kdb process

tableConsumer - A listener object that will consume only table messages from the kdb process

Throws:

KdbTargetProcessUnavailableException - If the consumer cannot connect to the target kdb process

NullPointerException - If either tables or syms is null. Also if both rawDataConsumer and tableConsumer null, the constructor must be passed one or the other

KdbConsumer

protected KdbConsumer(KdbProcess server,
                      KdbDict subscriptionConfiguration,
                      IKdbRawDataConsumer rawDataConsumer,
                      IKdbTableConsumer tableConsumer)
               throws KdbTargetProcessUnavailableException

Throws:

KdbTargetProcessUnavailableException

KdbConsumer

public KdbConsumer(KdbProcess server,
                   List<String> tables,
                   IKdbTableConsumer tableConsumer)
            throws KdbTargetProcessUnavailableException

Throws:

KdbTargetProcessUnavailableException

See Also:

KdbConsumer(KdbProcess, List, IKdbRawDataConsumer, IKdbTableConsumer)

Method Detail

subscribeAndListen

public void subscribeAndListen()
                        throws KdbProcessSubscriptionFailedException

Once connection to the process has been established (performed during object construction), then this function is called to first subscribe to the kdb TickerPlant and, if successful, start listening for update messages

Throws:

KdbProcessSubscriptionFailedException - If the subscription to the TickerPlant fails

See Also:

subscribe(), listen()

reconnect

public void reconnect()

Performs the reconnection logic as defined in the super class. If the reconnection is successful then we re-subscribe to the process before continuing to listen for update messages.

Overrides:

reconnect in class KdbConnection

See Also:

KdbConnection.reconnectIntervalMs

subscribe

private Boolean subscribe()
                   throws UnsupportedOperationException

Performs a subscription request to the kdb process (.u.sub) with the specified list of tables and symbols specified at object construction time

Returns:

True if the subscription result from the kdb process is not null, false otherwise

Throws:

UnsupportedOperationException

listen

private void listen()

Commences listening for messages to be sent to this consumer from the kdb process. The thread this object is running in will block waiting for each message and then route the message to the two listener objects as appropriate

See Also:

rawDataConsumer, tableConsumer