The central entrypoint is the DataFlowTemplate class in package org.springframework.cloud.dataflow.rest.client.
This class implements the interface DataFlowOperations and delegates to sub-templates
that provide the specific functionality for each feature-set:
| Interface | Description |
|---|---|
StreamOperations | REST client for stream operations |
CounterOperations | REST client for counter operations |
FieldValueCounterOperations | REST client for field value counter operations |
AggregateCounterOperations | REST client for aggregate counter operations |
TaskOperations | REST client for task operations |
JobOperations | REST client for job operations |
AppRegistryOperations | REST client for app registry operations |
CompletionOperations | REST client for completion operations |
RuntimeOperations | REST Client for runtime operations |
When the DataFlowTemplate is being initialized, the sub-templates will be discovered
via the REST relations, which are provided by HATEOAS.[1]
![[Important]](images/important.png) | Important |
|---|---|
If a resource cannot be resolved, the respective sub-template will result in being NULL. A common cause is that Spring Cloud Data Flow offers for specific sets of features to be enabled/disabled when launching. For more information see Chapter 13, Controlling features with Data Flow server. |