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Join Actor

The join actor merges multiple branches formed by a split task back into a single path. The actor is configured to expect a specific number of arrivals of records with the same record or tracking identifier. Once the expected number of each arrive the exit link is followed. Options for how to form the outgoing JSON record are also available with the box_resolve parameter.

The task follows the first or only link to the next task. No link label is needed.

The JSON used to designate a join task in a flow description is:

    "task-x": {
        "actor": "join",
        "trace": false,
        "count": 2,
        "box_resolve": "merge",
         "links": {
            "": "task-y"

Parameters the join expects are:

count The number of arrivals with the same record identifier before transitioning.
box_resolve The stategy to use for resolving how the contents of the outgoing record or box will be formed. Since the order of arrival can vary care should be used to avoid unexpected results. Options are:
merge Merge JSON object or arrays.
first The outgoing record will be the first record received.
last The outgoing record will be the last record received.
all All records are placed in an array that becomes the record for the outgoing record.