48. Overview

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:

InterfaceDescription

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]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.



[1] HATEOAS stands for Hypermedia as the Engine of Application State