START_LISTEN - Atoti Hub

Overview

This operation will keep the listening stream open in the background. If a stream is opened on a directory, and that directory contains data, then the data will be loaded immediately when the stream is opened. Streams can be closed by using the STOP_LISTEN operation. The status of an open stream can be retrieved using the LIST_STATUS operation. The START_LISTEN operation can act on any fetching Topic.

Request

Java
JSON

`DlcStartListenRequest`

Key	Required	Type	Description
topics	Y	`Set<String>`	Set of topics or aliases.
topicOverrides		`Set<ILoadingTopicDescription>`	Topic overrides.
scope		`IDlcScope`	Scope Parameters
branch		`String`	The branch to operate on.
performGcOnStart		`Boolean`	Perform a Garbage collection before the datastore transaction.
performGcOnCompletion		`Boolean`	Perform a Garbage collection after the datastore transaction.
sourceName		`String`	The source name to operate on. See source to topic matching.
sourceType		`DlcSourceType`	The source type to operate on. See source to topic matching.

Example:

DlcStartListenRequest.builder()
    .topics("Topic1", "Topic2") // Required
    .topicOverrides(Set.of(CsvTopicDescription.builder("TopicToOverride", "glob:file*.csv")...build()))
    .scope(DlcScope.of("ScopeKey1", "ScopeValue1"))
    .branch("BranchToLoadInto")
    .sourceName("NameOfSourceToUse")
    .sourceType(DlcSourceType.LOCAL_SOURCE)
    .build();

`DlcStartListenRequestDTO`

Key	Required	Type	Description
topics	Y	`Set<String>`	Set of topics or aliases.
csvTopicOverrides		`Map<String, CsvTopicProperties>`	CSV Topic overrides.
scope		`Map<String, Object>`	Scope Parameters
branch		`String`	The branch to operate on.
performGcOnStart		`Boolean`	Perform a Garbage collection before the datastore transaction.
performGcOnCompletion		`Boolean`	Perform a Garbage collection after the datastore transaction.
sourceName		`String`	The source name to operate on. See source to topic matching.
sourceType		`DlcSourceType`	The source type to operate on. See source to topic matching.

Example:

{
  "operation": "START_LISTEN",
  "topics": ["Topic1", "Topic2"],
  "csvTopicOverrides": {
    "TopicToOverride": {
      "path": "glob:file*.csv"
    }
  },
  "scope": {
    "ScopeKey1": "ScopeValue1"
  },
  "branch": "BranchToLoadInto",
  "performGcOnStart": true,
  "performGcOnCompletion": true,
  "sourceName": "NameOfSourceToUse",
  "sourceType": "LOCAL_SOURCE"
}

Response

Java
JSON

`DlcStartListenResponse`

Key	Type	Description
report	`StartListenReport`	Report of what occurred during the `START_LISTEN` operation.
status	`DlcStatus`	Status of the DLC Operation.

`StartListenReport`

Key	Type	Description
listenIdPerTopic	`Map<String, String>`	A unique identifier to the stream that was opened for each Topic.

`DlcStatus`

A simple enum to capture if the DLC request was executed.

Key	Description
OK	Request was handled successfully.
ERROR	Request was not able to be performed correctly.

`DlcStartListenResponseDTO`

Key	Type	Description
listenIdPerTopic	`Map<String, String>`	A unique identifier to the stream that was opened for each Topic.

Example:

{
  "listenIdPerTopic": {
    "Topic1": "4320",
    "Topic2": "6550"
  },
  "status": "OK"
}

How it works

File source types

For file source types, the DLC will register a file listener and start listening on the specified topics. When the file watcher is notified of file updates, the DLC listen operation will execute a DLC LOAD operation to load the files that have been updated. This means that the listen operation will simply execute a LOAD operation on all file updates.

​Overview

​Request

​DlcStartListenRequest

​Example:

​DlcStartListenRequestDTO

​Example:

​Response

​DlcStartListenResponse

​StartListenReport

​DlcStatus

​DlcStartListenResponseDTO

​Example:

​How it works

​File source types

Overview

Request

`DlcStartListenRequest`

Example:

`DlcStartListenRequestDTO`

Example:

Response

`DlcStartListenResponse`

`StartListenReport`

`DlcStatus`

`DlcStartListenResponseDTO`

Example:

How it works

File source types