Input Pin   An input pin is a type of object node, that gives the node the capability of storing (buffering) tokens. Input pins are owned by actions and tokens may accumulate at an input pin waiting to be consumed by the action. Input pins only have incoming flows all of which must be object flows, and they provide values to the actions that consume the tokens.

Explanation

Actions often require input in the form of data or objects to carry out their work. Input pins provide a mechanism for presenting this information to the action and analogously output pins provide a place for actions to place the results of their work. Input pins are typically positioned on the side of an action and receive incoming object flows, which contain data or objects. They do not have outgoing flows but rather pass their tokens directly to the action that owns the input pin. In our daily lives we see examples of input pins. The in-tray on an office-worker's desk is like an input pin. Items are placed in the in-tray in a particular order, are generally of a particular type and in a particular state, (for example a refund waiting for approval), they can accumulate (pile up), and are typically attended to in a fixed order. The items are removed from the in-tray; some work is carried out by the office worker typically using the token from the in-tray as whole or partial input into the work. Any results or outputs of the work are placed in the out-tray; they will typically be collected from the out-tray by another office worker and placed in the in-tray at another worker's desk.

Important Points

		Input pins are owned by actions.		Input pins provide data or objects to actions and are owned by one (and only one) action.
		Input pins can have one or more incoming object flows but no outgoing flows.		An input pin can have any number of incoming flows all of which must be object flows but cannot have any outgoing flows as all tokens are passed directly to the action that owns the pin.

Related Entries

Output Pin  Paired Element,  Graphically Similar An output pin is related to an input pin in that they are paired elements and both elements are owned by an action. They have a similar appearance and can be distinguished by the fact that an input action has incoming flows with the arrowhead pointing towards the pin whereas an output pin has outgoing flows with the arrowheads pointing away from the pin.

Action  Used Together An action is related to an input pin in that the action owns the input pin. The input pin receives object tokens from incoming object flows making them available to the action.