Mappings

The Mappings interface is used to build up key/destination mappings that are applied on top of the full Dispatch payload before it is sent to a given Dispatcher.

Keys that are not mapped to are kept as they are, while a mapped destination replaces any existing value. The only exception is the root Dispatch.Keys.COMMAND_NAME key, where mapped values (constants or variables) are appended to any value already there, flattening lists one level, so that multiple commands can be collected (e.g. an existing ["a"] with a mapped ["b", ["c"]] gives ["a", "b", ["c"]]). If a parent along the destination path holds a value of a different type (e.g. a string where an object is needed, or an object where a list is needed), it is replaced. Sources are always read from the original payload, so mappings don't chain. Derived values should be computed with a dispatcher-scoped transformation, which runs before mappings.

Use the multiple mapFrom methods to supply the required source "key" and "destination" key, as well as any optional "path" entries required to access keys in nested object.

Using the following payload DataObject as an example (shown as JSON)

{
     "source" : "value",
     "path": {
         "to" : {
             "source": "nested value"
         }
     }
}

Simple usage for keys in the top level DataObject would look like so:

mapFrom("source", "destination")

More complex versions requiring accessing keys that exist in nested objects would look like so:

mapFrom(JsonPath["path"]["to"]["source"], JsonPath["path"]["to"]["destination"])

The mapFrom method returns a VariableOptions that allows for setting optional properties relevant to a mapping.

See also

Inheritors