Adding a transition to a state machine

A transition channels execution from one state to the next by recognizing the triggering event, evaluating the conditions necessary for execution to flow through it, and determining what actions can occur should execution be allowed. An event can trigger more than one transition at a time, but only one of those transitions will fire.

To add a transition, proceed as follows:
  1. Drop a state onto the canvas.
  2. Move the cursor over the state until the yellow "lollipop" appears above it as shown in this image.
    The yellow 'lollipop' appears when you highlight a state on the canvas.
  3. Hold the left mouse button The cursor will change appearance, and will look like a crossed out circle.
  4. Drag the cursor out over the canvas. When you hover over a valid target, the crossed out circle disappears.
  5. Click the activity that you want to link to. A dark grey arrow will appear on the canvas linking the source and target activities.
  6. To designate the transition's visual path on the canvas, right-click the transition, select Layout and choose from one of the following two options:
    Option Description
    Bendpoint This is the default setting, and will automatically choose the shortest and most direct path. You can manually adjust this path by selecting the transition, clicking the tiny black box that appears at the midpoint of the transition, and then dragging it to a new location. Two new black boxes will appear at the mid-point of each half, and you can adjust these as well until the transition appears on the canvas as you want.
    Rectilinear Choose this setting to have the transition automatically drawn for you. The bends will always be at ninety degree angles.
    You will only see one of these options at a time. When one option appears in the drop-down menu, then the other one is, by default, the active choice.
Note: Exceptions that occur while processing a user action are ignored and the transition continues in all cases except one: When the triggering event is a call event and the operation defines a fault message, the transition will stop and the fault will be propagated back to the caller. Control will remain in the current state for this one case.
Click on one of the following links to configure this new transition.
Related tasks
Working with composite states
Adding a state to a state machine
Adding an entry or an exit action to a state

Feedback
(C) Copyright IBM Corporation 2005, 2007. All Rights Reserved.