com.pushtechnology.diffusion.client.topics.details

Enum TopicType

java.lang.Object

java.lang.Enum<TopicType>

com.pushtechnology.diffusion.client.topics.details.TopicType

All Implemented Interfaces:

Serializable, Comparable<TopicType>

public enum TopicType
extends Enum<TopicType>

The topic type determines the type of the data values a topic publishes to subscribers.

Source Topics

Most topics are source topics. The characteristics of each type of source topic are summarized in the following table.

Topic type	State	Data type
STRING	Single scalar value.	String.
INT64	Single scalar value.	64-bit integer.
DOUBLE	Single scalar value.	Double precision floating point number.
BINARY	Single scalar value.	Arbitrary binary data.
RECORD_V2	Single composite value.	RecordV2 – Diffusion-specific data type. A list of records, each composed of field values, with an optional schema.
JSON	Single composite value.	JSON, backed by CBOR-format binary.
TIME_SERIES	Append-only log of events.	TimeSeries.Event containing a value of a well-known data type.

Routing Topics (deprecated)

A ROUTING topic can have a different source topic for each subscription.

Routing topics republish values from source topics. The data type is inherited from the source topic.

Routing topics are deprecated in favor of SessionTrees.

Since:

5.0

Author:

DiffusionData Limited

See Also:

TopicSpecification

Enum Constant Summary

Enum Constants

Enum Constant and Description
BINARY Topic that stores and publishes binary values.
DOUBLE Topic that stores and publishes IEEE 754 double-precision floating point numbers.
INT64 Topic that stores and publishes 64-bit integer values.
JSON Topic that stores and publishes JSON (JavaScript Object Notation) values.
RECORD_V2 Topic that stores and publishes data in the form of records and fields.
ROUTING Deprecated. since 6.7 Routing topics are deprecated. The more powerful SessionTrees feature should be used in their place.
STRING Topic that stores and publishes String values.
TIME_SERIES Time Series Topic.
UNKNOWN_TOPIC_TYPE A topic type that is unsupported by the session.

Method Summary

Modifier and Type	Method and Description
static TopicType	valueOf(String name) Returns the enum constant of this type with the specified name.
static TopicType[]	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 Detail

ROUTING

@Deprecated
public static final TopicType ROUTING

Deprecated. since 6.7

Routing topics are deprecated. The more powerful SessionTrees feature should be used in their place.

Routing Topic.

A topic that can reference different source topics for different sessions.

Each subscription to a routing topic is routed to a source topic. Updates to the source topic are routed back to the subscriber and appear to come from the routing topic.

The result is that a session may subscribe to a topic which is in reality supported by another topic and the mapping of the routing topic to the actual topic can be different for each session.

As an example, you may wish for all sessions to simply subscribe to a topic called "Prices" but depending upon the client type the actual topic could differ (Prices/Discount, Prices/Standard etc).

An instance of this topic may map any number of sessions to any number of different source topics.

From the point of view of a session subscribing to such a topic, a routing topic appears to be a normal topic but it has no state of its own and cannot be updated.

The mapping of sessions to source topics is performed by a control client session using the SubscriptionControl feature. When a session subscribes to the routing topic the control client is requested to provide the topic that the client is to be subscribed to. If there is no control client available to handle subscriptions at the time a session subscribed, the session will not be subscribed to the topic.

Alternatively, the routing can be determined by a user-written Java class (deployed on the server) which will be invoked to define the mapping of the topic to another data topic when a session subscribes.

When a source topic is removed that is mapped to from a routing topic then any session that were mapped to that source topic will be unsubscribed from the routing topic.

JSON

public static final TopicType JSON

Topic that stores and publishes JSON (JavaScript Object Notation) values. Based on the JSON data type.

Supports delta-streams.

Since:

5.7

BINARY

public static final TopicType BINARY

Topic that stores and publishes binary values. Based on the binary data type.

Supports delta-streams.

Since:

5.7

RECORD_V2

public static final TopicType RECORD_V2

Topic that stores and publishes data in the form of records and fields. Based on the RecordV2 data type.

Supports delta-streams.

Since:

6.0

DOUBLE

public static final TopicType DOUBLE

Topic that stores and publishes IEEE 754 double-precision floating point numbers. Based on the double data type.

Supports null Double values.

The topic does not support delta-streams — only complete values are transmitted.

Since:

6.0

INT64

public static final TopicType INT64

Topic that stores and publishes 64-bit integer values. Based on the int64 data type.

Supports null Long values.

The topic does not support delta-streams — only complete values are transmitted.

Since:

6.0

STRING

public static final TopicType STRING

Topic that stores and publishes String values. Based on the string data type.

Supports null String values.

Supports delta-streams.

Since:

6.0

TIME_SERIES

public static final TopicType TIME_SERIES

Time Series Topic.

A time series is a sequence of events. Each event contains a value and has server-assigned metadata comprised of a sequence number, timestamp, and author.

A time series topic allows sessions to access a time series that is maintained by the server. A time series topic has an associated event data type, such as Binary, String, or JSON, that determines the type of value associated with each event.

Retained range

The TIME_SERIES_SUBSCRIPTION_RANGE property configures the range of historic events retained by a time series topic. If the property is not specified, a time series topic will retain the ten most recent events.

Subscription range

The TIME_SERIES_SUBSCRIPTION_RANGE property configures a time series topic to send a range of historic events from the end of the time series to new subscribers. This is a convenient way to synchronize new subscribers without requiring the use of a range query.

By default, new subscribers will be sent the latest event if delta streams are enabled and no events if delta streams are disabled. See the description of Subscription range in the time series feature documentation.

Mandatory properties

The TIME_SERIES_EVENT_VALUE_TYPE property must be provided when creating a time series topic.

Since:

6.0

See Also:

TimeSeries

UNKNOWN_TOPIC_TYPE

public static final TopicType UNKNOWN_TOPIC_TYPE

A topic type that is unsupported by the session.

Since:

6.1

Method Detail

values

public static TopicType[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (TopicType c : TopicType.values())
    System.out.println(c);

Returns:

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

valueOf

public static TopicType 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