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The channel is a passive component of a system. Agents can transmit information through it. Different from a storage, information written on a channel is volatile, being visible just in the moment of transmission by the sending agent. Therefore it is only useful for communication purposes. It is possible that more than two agents contribute to the communication process, e.g. in a broadcast / subscriber scenario. |
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The communication channel connects two agents. The information can flow in both directions. |
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The request / response channel also connects two agents, but the flow of information is determined by the direction of the request / response symbol. The request is sent as indicated by the request / response symbol and the response is returned in just the opposite direction. |
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This communication bus is used for broadcast communication. More than two agents are connected with it. |
You can move the channel by selecting the channel (not its edges) and dragging it to another location. You can modify the shape of the channel by clicking it twice (green handles) and dragging one of the handles.
You can delete the channel by selecting it (blue dotted outline) and pressing [Del] or by selecting Delete in the context menu.
Channel comments are used to show the information transmitted via a channel or the protocol used. To create a comment, select the channel and click Create Comment in the context menu. To change a comment, select the channel and click Set Comment in the context menu. To delete a channel comment, select the channel and click Delete Comment in the context popup menu.
The request symbol can only be created for channels that have exactly two connecting edges. To create the request symbol, select the channel and click Create Request Symbol in the context menu. If you wish to switch the direction of the request symbol, select the channel and click Flip Request Symbol in the context menu. To delete a request symbol, select the channel and click Delete Request Symbol in the context popup menu.
Each channel can have an arbitrary number of edges. The edges are always connected with one end to the channel. You can select a channel edge by clicking twice on the edge. The first click selects the whole channel (blue lines) and the second click selects the edge (green lines). You can delete a channel edge by pressing [Del] and you can move an edge by dragging it. Please note that you can only move a channel edge alongside the channel knob. In particular you cannot disconnect it from the channel knob.
To add an edge to a channel, select the channel knob by clicking it twice. The first click will select the entire channel (blue lines) and the second will select the channel knob only (green lines). You can now draw a new channel edge by moving the mouse pointer to one of the handles in the middle of either side of the channel knob, pressing [Ctrl] and dragging the mouse while keeping [Ctrl] pressed.
You can indicate that a channel occurs multiple times by selecting the agent, clicking with the right mouse button and picking Create shadow in the context menu.
You can remove the multiple instances by clicking the channel with the right mouse button and selecting Remove shadow in the context menu.