ee.telekom.workflow.graph.Node Maven / Gradle / Ivy
package ee.telekom.workflow.graph;
import ee.telekom.workflow.core.workitem.WorkItem;
/**
* A {@link Node} corresponds to an action in a workflow definition. E.g. it may
* perform some function. In some cases it may not complete immediately, but
* enter a wait state. At some point it will be completed and the execution can
* continue.
*
*
*
* Every node may have multiple outgoing {@link Transition}s. When a node is
* completed, it may pick which transition(s) to proceed trough.
*
*
*
* Note, that node implementations may not contain any {@link GraphInstance}
* specific execution state. If a node implementation requires such state, this
* state either must reside in the {@link Token} implementation or in the
* graph instance's {@link Environment}.
*/
public interface Node{
/**
* Returns the node's unique id. The id must be unique to the containing
* {@link Graph}.
*
* @return the node's unique id
*/
int getId();
/**
* Returns the node's name. A node may have a name describing it within the
* workflow.
*
* @return the node's name
*/
String getName();
/**
* Performs node specific logic. Either from the execute method, or later
* from the outside, the {@link GraphEngineFacade#complete(WorkItem)} method
* must be called to continue executing the {@link GraphInstance}.
*
* @param engine
* the {@link GraphEngine} which is performing the execution
* @param token
* the {@link Token} which is currently executing in this node
*/
void execute( GraphEngine engine, Token token );
/**
* Called when the {@link GraphEngine} cancels the execution of a
* {@link Token}, that is currently pointing to this node and is in a wait
* state.
*
* @param engine
* the {@link GraphEngine} which is performing the execution
* @param token
* the {@link Token} pointing to this node
*/
void cancel( GraphEngine engine, Token token );
/**
* When a token execution on a node completes and returns control back to
* the engine, then the engine mandates the node to store the node execution
* result into the graph instance's environment.
*
* @param environment
* the environment to store the result in
* @param result
* the result to be stored
*/
void store( Environment environment, Object result );
}