Plugin Connector

What is a `Connector`?

A connector connects a property of the outbound entity instance with a property of the inbound entity instance and propagates the changes of the value.

During propagation a propagation function is called. The propagation function has one single input (the incoming value). Connectors of different types has different propagation functions.

The propagation function can only do simple things (like casting or logging) but in fact even these simple operations makes the control flow much simpler and much more readable.

How does a connector work?

The connector is a relation instance which connects two entity instances. The relation itself stores the names of the output property and the input property.

In theory, it's also possible to connect two properties of the same entity instance.

On construction the streams are connected.

On destruction of the connector, the stream will be removed.

Warning

Connecting properties of the same entity instance is discouraged to prevent feedback loops
No type checks are performed on construction (yet; you are responsible)
There is no check about feedback loops (yet; you are responsible)
Renaming the relation properties (outbound_property_name, inbound_property_name) doesn't have any effect (yet). You have to remove the old connector and recreate a new connector.

Components

Name	Description	Properties	Data Type	Socket Type
connector	Connects two properties	outbound_property_name	string	none
		inbound_property_name	string	none

buffer	A buffer for FIFOs and interpolation	buffer_size	number	none
		buffer	array	none

propagation_counter	Counts connector propagations. This component can be applied on all types of connectors	propagation_count	number	none

Relation Types

Name	Components	Description
buffered_fifo_connector	connector	This connector propagates the first inserted value of the FIFO buffer with the given size
	buffer
debounce_connector	connector	This connector propagates the value if and only if the value is different
debug_connector	connector	This connector logs the value before propagation (log level debug)
default_connector	connector	This is the default connector type, which simply does nothing than propagate the value
delay_connector	connector	This connector propagates the value after a given duration. This operation is blocking
numeric_interpolation_connector	connector	This connector propagates the average of the numeric elements in the buffer
	buffer
parse_float_connector	connector	This connector parses a string value and propagates a float value
parse_int_connector	connector	This connector parses a string value and propagates a int value
to_string_connector	connector	This connector converts the value of any type to string before propagation
trace_connector	connector	This connector logs the value before propagation (log level trace)
increment_by_connector	connector	This connector adds the value of the outbound property to the value of the inbound property
decrement_by_connector	connector	This connector subtracts the value of the outbound property from the value of the inbound property

Future: More (useful) connectors

Name	Components	Description
str_split_connector	connector	A string is split into tokens. Propagates an JSON array of string tokens
str_join_connector	connector	Joins an array of strings and propagates the resulting string

Platform Compatibility

Platform	Compatibility
Linux	✓
MacOS	✓
Windows	✓

Repository

Name	Repository
reactive-graph-plugin-connector	https://github.com/reactive-graph/plugins-core/tree/main/plugins/connector

Usage

GraphQL: Create a new connector

mutation {
  instances {
    relations {
      createConnector: create(
        edgeKey: {
          outboundId: "dc82735e-28ec-4c24-aedb-d968b73b288f",
          typeName: "default_connector--value--value"
          inboundId: "4cf8e6d8-f92e-4ffa-9610-ec0635f55e08",
        },
        properties: [
          {
            name: "outbound_property_name",
            value: "value"
          },
          {
            name: "inbound_property_name",
            value: "value"
          }
        ]
      ) {
        type {
          name
          fullName
        },
        properties(
          names: [
            "outbound_property_name",
            "inbound_property_name"
          ]
        ) {
          name
          value
        }
      }
    }
  }
}

Reactive Graph