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Design concepts
Learn about HCL Link services, projects, flows, maps and schemas.
Flows
A HCL Link flow is a transactional data flow comprised of processing nodes.
Introduction to Flows
This documentation describes how Flows can be run from REST API, listeners, or they can be scheduled.
Nodes
REST Client Node
The REST Client Node provides a simple and powerful way to access REST services.
Functionality
The REST Client Node operates in General, Configuration Script and Configuration Package modes.

Design concepts
Learn about HCL Link services, projects, flows, maps and schemas.
- Introduction
  The documentation provided here defiens the main artifacts in HCL Link. It is necessar to understand what these artifacts are and the relationship between them.
- Services
  Service definitions define REST services and the endpoints of a service.
- Projects
  A project is a container for HCL Link artifacts.
- Flows
  A HCL Link flow is a transactional data flow comprised of processing nodes.
  - Introduction to Flows
    This documentation describes how Flows can be run from REST API, listeners, or they can be scheduled.
    - Nodes
      - Map Node
        A Map Node invokes an HCL Link map within a flow.
      - Flow Node
        A Flow node invokes a sub-flow within a flow.
      - Source and Target Nodes
        Source and Target Nodes provide HCL Link with an outside-in approach to developing integrations.
      - Request Node
        The Request Node has a single input request terminal and a single output response terminal.
      - Cache Read and Write Nodes
        Cache Read and Cache Write node functionality is described in this section.
      - Clone Node
        The Clone Node has one input and two output terminals.
      - Decision Node
        The Decision Node routes input data to the true, or false terminals depending upon the condition.
      - Fail Node
        The Fail Node causes the flow execution to fail.
      - Format Converter Node
        The Format Converter Node can be used to quickly convert data from one format to another.
      - JSON Read Node
        This documentation describes the function and use of the JSON Read Node.
      - JSON Transform Node
        The JSON Transform node is used to transform JSON documents from one form to another.
      - Java Node
        The Java Node invokes a Java class, thus performing user defined functionality based on the properties specified for the Java class to act on the input.
      - Join Node
        The Join Node gathers the individual results and appends to a single output file or terminal.
      - Log Node
        The Log Node logs the raw data from the node input into the file and propagates the data from the input to the output terminal.
      - Passthrough Node
        The Passthrough Node propagates data from the input to the output terminal.
      - REST Client Node
        The REST Client Node provides a simple and powerful way to access REST services.
        Functionality
        The REST Client Node operates in General, Configuration Script and Configuration Package modes.
        Terminals
        The REST Client Node supports a number of terminals.
        Settings
        This section lists the settings available for the REST Client node.
        Authentication
        Provides the options to authenticate the connection. This is an optional property.
        Input Data Request Mode
        Input Data Request Mode is available, when you set Configuration Mode to Configuration Packages.
        Request Assignments
        Provides a quick and easy way to build request data, when the request data is not provided to the node's input terminal.
        Response Assignments
        Response Assignments are used to set flow variables based on values of elements of the response. This provides a simple way to parse responses to extract elements from the responses.
        Logging
        Specifies the level of logging to use for the log (trace) file produced by the node.
      - Route Node
        The Route Node provides a way to route data conditionally to one or more outputs of the node. The node bases decisions by evaluating a condition for a flow variable and determining whether to send the data to output 1 or 2 or both, based on the result of the condition.
      - Sleep Node
        The Sleep Node suspends the execution of the flow for the specified number of milliseconds
      - Split Node
        A Split Node should be used when there is a need to split CSV data processing. This might occur when CSV data processing becomes excessively time consuming.
    - Terminals
    - Flow terminals
      Flow terminals represent the inputs and outputs to a flow. Every node has input and/or ouptut terminals.
    - Scheduled flows
      This documentation describes the options for defining the flow schedule.
    - Listener
      A Flow that has a Map node as its first node, and uses a File adapter for an input, can enable that node's input to be a Watch.
    - Flow audits
      Flow audits are a way to retrieve more verbose information about a flow instance.
    - Flow variables
      Flow Variables are process data variables that go along with the flow execution, accessible to all nodes in the flow while it is being executed under flow executor/engine context.
    - Create a flow
      Steps required to create a flow.
    - Running flows in the Designer
      When you develop a flow in the Flow Designer you can run the flow directly from the Designer either in Link, or on a different runtime environment.
- Maps
  A HCL Link map defines how to generate data that complies to a specific schema. A map can have any number of inputs and outputs.
- Schemas
  Schemas specify the format of data witin HCL Link maps and flows.
- Connections and Actions
  This documentation describes connections and actions.
- Files
  Files are used in various places within HCL Link. HCL Link allows files to be uploaded to the HCL Linkserver.
- Flow variables
  Flow variables provide a means of passing information throughout a flow instance without requiring that the information to be passed through data links. flow variables are name-value pairs that persist, unless deleted.
- Cache variables
  Cache variables provide a means of processing information throughout a flow instance without requiring that the information to be passed through data links.

Functionality

The REST Client Node operates in General, Configuration Script and Configuration Package modes.

The REST Client Node modes are described here:

General: Specifies URL, method and other properties.
Configuration Script: References a script (JSON file) that contains the endpoint definitions.
Configuration Package: References a package (jar file) that contains the endpoint definitions, input/output formats and optionally Java plugin code.