State Datatype
Description
A state is an immutable datastructure that defines a collection of available transitions, management operations, and possibly initialization or termination triggers. Actionable features of a state are exposed when the state is within the current state path. The current state path is a path composed of the current state, it's parent, parent's patrent, etc. unit the root state is reached. As such, any operations declared within the root state will always be available where operations and/transitions in sub-states will only available if the associated state is present in the state path.
Attributes
| name | Set the state name. |
| terminal | If set to 'true' the state will be classified as a terminal state. |
Nested Elements
| trigger | An initialization or termination trigger. |
| state | A nested state. |
| transition | A state transition. |
| operation | A management operation. |
Example
<project name="standalone-graph-example" default="install"
xmlns:transit="antlib:dpml.tools.transit"
xmlns:x="dpml:depot"
xmlns:c="dpml:metro">
<transit:import uri="local:template:dpml/tools/standard"/>
<target name="build" depends="standard.build">
<x:plugin uri="link:plugin:dpml/metro/dpml-metro-tools"/>
<c:state>
<trigger event="initialization">
<transition name="startup" target="started">
<operation method="start"/>
</transition>
</trigger>
<state name="started">
<trigger event="termination">
<apply id="stop"/>
</trigger>
<transition name="stop" target="../stopped">
<operation method="stop"/>
</transition>
</state>
<state name="stopped">
<transition name="start" target="../started">
<operation method="start"/>
</transition>
</state>
</c:state>
</target>
</project>