Package oracle.kv.pubsub

Class NoSQLPublisher

java.lang.Object

oracle.kv.pubsub.NoSQLPublisher

All Implemented Interfaces:

Publisher<StreamOperation>

public class NoSQLPublisher
extends java.lang.Object
implements Publisher<StreamOperation>

Object represents a NoSQLPublisher which publishes changes to the NoSQL store on order, an implementation of Reactive Streams Publisher interface. For each kvstore, limit one instance of NoSQLPublisher running on a single JVM. For repeated request of publisher with same configuration, the same instance will be returned to user. If user requests a publisher instance to a kvstore with existing publisher, but with different configuration parameters, an exception will be raised to user. However, user is able to change the parameters of an existing publisher.

Field Summary

Fields

Modifier and Type	Field	Description
static int	DEFAULT_MAX_CONCURRENT_SUBS	Default maximum number of subscriptions.
static long	DEFAULT_SHARD_TIMEOUT_MS	Default shard timeout in milliseconds.

Method Summary

Modifier and Type	Method	Description
void	close(boolean delDir)	Closes a publisher without error, shut down all connection to source and free resources.
void	close(java.lang.Throwable cause, boolean delDir)	Closes a publisher, shut down all connection to source and free resources.
static NoSQLPublisher	get(NoSQLPublisherConfig config)	Returns a handle to the NoSQL publisher after verifying that the store exists and is accessible.
static NoSQLPublisher	get(NoSQLPublisherConfig config, java.util.logging.Logger logger)	Returns a handle to the NoSQL publisher after verifying that the store exists and is accessible.
static NoSQLPublisher	get(NoSQLPublisherConfig config, LoginCredentials loginCred)	Returns a handle to the NoSQL publisher after verifying that the store exists and is accessible.
static NoSQLPublisher	get(NoSQLPublisherConfig config, LoginCredentials loginCred, java.util.logging.Logger logger)	Returns a handle to the NoSQL publisher after verifying that the store exists and is accessible.
long	getStoreId()	Gets kvstore store id
java.lang.String	getStoreName()	Gets the kvstore name
boolean	isClosed()	Returns true is the publisher has already shutdown
void	subscribe(Subscriber<? super StreamOperation> s)	A Subscriber establishes a NoSQL Subscription to initiate the flow of elements from the Publisher.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_MAX_CONCURRENT_SUBS

public static final int DEFAULT_MAX_CONCURRENT_SUBS

Default maximum number of subscriptions.

See Also:

Constant Field Values

DEFAULT_SHARD_TIMEOUT_MS

public static final long DEFAULT_SHARD_TIMEOUT_MS

Default shard timeout in milliseconds.

See Also:

Constant Field Values

Method Detail

get

public static NoSQLPublisher get(NoSQLPublisherConfig config)

Returns a handle to the NoSQL publisher after verifying that the store exists and is accessible. An existing publisher instance will be returned if possible. If security is configured with the system properties, this method will return a NoSQL publisher to a secure store. However if no security is configured, this method will return return a NoSQL publisher for non-secure store.

Parameters:

config - publisher configuration

Returns:

an instance of the publisher

Throws:

PublisherFailureException - if unable to create a publisher

get

public static NoSQLPublisher get(NoSQLPublisherConfig config,
                                 java.util.logging.Logger logger)
                          throws PublisherFailureException

Returns a handle to the NoSQL publisher after verifying that the store exists and is accessible. An existing publisher instance will be returned if possible. If security is configured with the system properties, this method will return a NoSQL publisher to a secure store. However if no security is configured, this method will return return a NoSQL publisher for non-secure store.

Parameters:

config - publisher configuration

logger - private logger

Returns:

an instance of the publisher

Throws:

PublisherFailureException - if unable to create a publisher

get

public static NoSQLPublisher get(NoSQLPublisherConfig config,
                                 LoginCredentials loginCred)

Returns a handle to the NoSQL publisher after verifying that the store exists and is accessible. An existing publisher instance will be returned if possible.

Parameters:

config - publisher configuration

loginCred - login credentials

Returns:

an instance of the publisher

Throws:

PublisherFailureException - if unable to create a publisher

get

public static NoSQLPublisher get(NoSQLPublisherConfig config,
                                 LoginCredentials loginCred,
                                 java.util.logging.Logger logger)
                          throws PublisherFailureException

Returns a handle to the NoSQL publisher after verifying that the store exists and is accessible. An existing publisher instance will be returned if possible.

Parameters:

config - publisher configuration

loginCred - login credentials

logger - private logger

Returns:

an instance of the publisher

Throws:

PublisherFailureException - if unable to create a publisher

subscribe

public void subscribe(Subscriber<? super StreamOperation> s)
               throws java.lang.NullPointerException

A Subscriber establishes a NoSQL Subscription to initiate the flow of elements from the Publisher. As part of the Subscription creation, the subscription configuration is obtained via NoSQLSubscriber.getSubscriptionConfig(). The configuration contains information needed by the Publisher to start or resume the stream. Normal completion of this method results in NoSQLSubscriber.onSubscribe(org.reactivestreams.Subscription)being invoked.

Each publisher can have at most one subscriber from a subscription group specified in NoSQLSubscriptionConfig. For example, for a subscription group with three subscribers, each must run in a separate publisher, preferably on separate nodes. In other words, within each Publisher, all concurrent subscriptions must be from distinct groups. If a user tries to subscribe two subscriptions from the same group to same Publisher, a SubscriptionFailureException will be raised.

Note his method is not allowed to throw any exceptions other than NullPointerException. All other exceptions must be delivered via onError, according to rule Publisher.9 in reactive stream spec.

Specified by:

subscribe in interface Publisher<StreamOperation>

Parameters:

s - subscriber trying to use the publisher

Throws:

java.lang.NullPointerException - if subscriber is null

close

public void close(boolean delDir)

Closes a publisher without error, shut down all connection to source and free resources. A closed publisher cannot be reopened, but user will be able to create a new instance of NoSQLPublisher.

Parameters:

delDir - true if delete the publisher root directory

close

public void close(java.lang.Throwable cause,
                  boolean delDir)

Closes a publisher, shut down all connection to source and free resources. A closed publisher cannot be reopened, but user will be able to create a new instance of NoSQLPublisher.

Parameters:

cause - null if normal close, otherwise it is the cause of failure that leads to publisher close.

delDir - true if delete the publisher root directory

getStoreId

public long getStoreId()

Gets kvstore store id

Returns:

kvstore store id

getStoreName

public java.lang.String getStoreName()

Gets the kvstore name

Returns:

kvstore name

isClosed

public boolean isClosed()

Returns true is the publisher has already shutdown

Returns:

true is the publisher has already shutdown