Package oracle.kv.pubsub

Enum NoSQLStreamMode

java.lang.Object

java.lang.Enum<NoSQLStreamMode>

oracle.kv.pubsub.NoSQLStreamMode

All Implemented Interfaces:

Serializable, Comparable<NoSQLStreamMode>

public enum NoSQLStreamMode
extends Enum<NoSQLStreamMode>

Subscription stream mode used to configure the starting point for a NoSQL subscription.

Enum Constant Summary

Enum Constants

Enum Constant	Description
FROM_CHECKPOINT	Start the stream from the last checkpoint saved in the checkpoint table, using the next available position for shards where the checkpoint position is not available.
FROM_EXACT_CHECKPOINT	Start the stream from the last checkpoint saved in the checkpoint table, signaling an exception if the checkpoint position is not available.
FROM_EXACT_STREAM_POSITION	Start the stream from the specified start stream position, signaling an exception if the requested position is not available.
FROM_NOW	Start the stream from the latest available stream position.
FROM_STREAM_POSITION	Start the stream from the specified start stream position, using the next available position for shards where the requested position is not available.

Method Summary

Modifier and Type	Method	Description
static NoSQLStreamMode	valueOf(String name)	Returns the enum constant of this type with the specified name.
static NoSQLStreamMode[]	values()	Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Details

FROM_NOW

public static final NoSQLStreamMode FROM_NOW

Start the stream from the latest available stream position. Any existing checkpoint or specified start stream position will be ignored.

Example use case

A user creates a new table "User" and wants to stream all updates made to that table after the subscription is created. She can configure the subscription with:

 final NoSQLSubscriptionConfig subscriptionConfig =
     new NoSQLSubscriptionConfig.Builder("MyCheckpointTable")
     .setSubscribedTables("User")
     .setStreamMode(NoSQLStreamMode.FROM_NOW)
     .build();
 

In order to receive all updates made to the table, the user should create the subscription before any updates are made to the table. If not, updates made to the table before the subscription is created may be missed.

FROM_EXACT_STREAM_POSITION

public static final NoSQLStreamMode FROM_EXACT_STREAM_POSITION

Start the stream from the specified start stream position, signaling an exception if the requested position is not available. Any existing checkpoint will be ignored.

If the requested start position is not available on the master for any shard, the subscription will fail and the publisher will signal SubscriptionInsufficientLogException to the subscriber via NoSQLSubscriber.onError(java.lang.Throwable).

If the requested start position is later than the currently available position on the master for any shard, then the stream will start from the highest position available on the master for that shard. This situation can happen in unusual cases where the store has performed a hard rollback.

Example use case

A user wants to stream all updates made to table "User" starting from a given stream position, and needs to be notified with an exception if the requested stream position is not available. She can configure the subscription with:

 final NoSQLStreamPosition position = ...; // given stream position
 final NoSQLSubscriptionConfig subscriptionConfig =
     new NoSQLSubscriptionConfig.Builder("MyCheckpointTable")
     .setSubscribedTables("User")
     .setStreamMode(NoSQLStreamMode.FROM_EXACT_STREAM_POSITION)
     .setStartStreamPosition(position)
     .build();
 

FROM_STREAM_POSITION

public static final NoSQLStreamMode FROM_STREAM_POSITION

Start the stream from the specified start stream position, using the next available position for shards where the requested position is not available. Any existing checkpoint will be ignored.

This mode is the same as FROM_EXACT_STREAM_POSITION except that the stream will start from the next position available on the master rather than signaling an exception for any shards where the requested start position is not available.

If the requested start position is later than the currently available position on the master for any shard, then the stream will start from the highest position available on the master for that shard. This situation can happen in unusual cases where the store has performed a hard rollback.

Example use case

A user wants to stream all updates made to table "User" starting from a given stream position, but can tolerate missing updates if the requested stream position is not available. She can configure the subscription with:

 final NoSQLStreamPosition position = ...; // given stream position
 final NoSQLSubscriptionConfig subscriptionConfig =
     new NoSQLSubscriptionConfig.Builder("MyCheckpointTable")
     .setSubscribedTables("User")
     .setStreamMode(NoSQLStreamMode.FROM_STREAM_POSITION)
     .setStartStreamPosition(position)
     .build();
 

FROM_EXACT_CHECKPOINT

public static final NoSQLStreamMode FROM_EXACT_CHECKPOINT

Start the stream from the last checkpoint saved in the checkpoint table, signaling an exception if the checkpoint position is not available. Any specified start stream position will be ignored.

If the checkpoint table does not exist and the publisher is allowed to create a new checkpoint table for the user, as specified by NoSQLSubscriptionConfig.Builder.setCreateNewCheckpointTable(boolean), then the checkpoint table will be created and the stream will start from the latest position available on the master for each shard. If the checkpoint table does not exist and the publisher is not allowed to create a new checkpoint table, the subscription will fail and the publisher will signal SubscriptionFailureException to the subscriber via NoSQLSubscriber.onError(java.lang.Throwable).

If the checkpoint position is not available on the master for any shard, the subscription will fail and the publisher will signal SubscriptionInsufficientLogException to the subscriber via NoSQLSubscriber.onError(java.lang.Throwable).

If the checkpoint position is later than the currently available position on the master for any shard, then the stream will start from the highest position available on the master for that shard. This situation can happen in unusual cases where the store has performed a hard rollback.

Example use case

A user wants to stream all updates made to table "User" from the last checkpoint, and needs to be notified with an exception if the checkpoint position is not available. She can configure the subscription with:

 final NoSQLSubscriptionConfig subscriptionConfig =
     new NoSQLSubscriptionConfig.Builder("MyCheckpointTable")
     .setSubscribedTables("User")
     .setStreamMode(NoSQLStreamMode.FROM_EXACT_CHECKPOINT)
     .build();
 

FROM_CHECKPOINT

public static final NoSQLStreamMode FROM_CHECKPOINT

Start the stream from the last checkpoint saved in the checkpoint table, using the next available position for shards where the checkpoint position is not available. Any specified start stream position will be ignored.

This mode is same as FROM_EXACT_CHECKPOINT except that the stream will start from the next position available on the master rather than signaling an exception for any shards where the checkpoint position is not available.

If the checkpoint start position is later than the currently available position on the master for any shard, then the stream will start from the highest position available on the master for that shard. This situation can happen in unusual cases where the store has performed a hard rollback.

Example use case

A user wants to stream all updates made to table "User" from the latest saved checkpoint, but can tolerate missing updates if the checkpoint stream position is not available. She can configure the subscription with:

 final NoSQLSubscriptionConfig subscriptionConfig =
     new NoSQLSubscriptionConfig.Builder("MyCheckpointTable")
     .setSubscribedTables("User")
     .setStreamMode(NoSQLStreamMode.FROM_CHECKPOINT)
     .build();
 

Method Details

values

public static NoSQLStreamMode[] values()

Returns an array containing the constants of this enum type, in the order they are declared.

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static NoSQLStreamMode valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null