io.nflow.engine.workflow.curated

Class CronWorkflow

java.lang.Object

io.nflow.engine.model.ModelObject

io.nflow.engine.workflow.definition.AbstractWorkflowDefinition<S>

io.nflow.engine.workflow.definition.WorkflowDefinition<CronWorkflow.State>

io.nflow.engine.workflow.curated.CronWorkflow

Direct Known Subclasses:

MaintenanceWorkflow

public abstract class CronWorkflow
extends WorkflowDefinition<CronWorkflow.State>

Workflow that wakes up periodically to execute a task.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	CronWorkflow.State States of cron workflow.

Field Summary

Fields

Modifier and Type	Field and Description
static String	VAR_SCHEDULE Name of the state variable that stores schedule in cron syntax.

Fields inherited from class io.nflow.engine.workflow.definition.AbstractWorkflowDefinition

allowedTransitions, failureTransitions

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	CronWorkflow(String type) Extend cron workflow definition.
protected	CronWorkflow(String type, WorkflowSettings settings) Extend cron workflow definition with customized workflow settings.

Method Summary

Modifier and Type	Method and Description
protected org.joda.time.DateTime	getNextActivationTime(StateExecution execution, String cron) Calculates next activation time based on cron state variable.
NextAction	handleFailure(StateExecution execution) Tries to handle failures by calling handleFailureImpl(io.nflow.engine.workflow.definition.StateExecution).
protected boolean	handleFailureImpl(StateExecution execution) Logs an error and continues.
NextAction	schedule(StateExecution execution, String cron) Determines the next execution time for the doWork state by calling getNextActivationTime.
NextAction	waitForWorkToFinish(StateExecution execution) Calls waitForWorkToFinishImpl(io.nflow.engine.workflow.definition.StateExecution) to check if this instance should wait for work to finish or move to schedule state.
protected org.joda.time.DateTime	waitForWorkToFinishImpl(StateExecution execution) Returns null to move to schedule state immediately if there are no incompleted child workflows, or current time plus 1 hour to check again later.

Methods inherited from class io.nflow.engine.workflow.definition.WorkflowDefinition

getStates

Methods inherited from class io.nflow.engine.workflow.definition.AbstractWorkflowDefinition

getAllowedTransitions, getDescription, getErrorState, getFailureTransitions, getInitialState, getMethod, getName, getSettings, getState, getSupportedSignals, getType, isAllowedNextAction, isStartState, permit, permit, setDescription, setName

Methods inherited from class io.nflow.engine.model.ModelObject

equals, hashCode, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

VAR_SCHEDULE

public static final String VAR_SCHEDULE

Name of the state variable that stores schedule in cron syntax.

See Also:

Constant Field Values

Constructor Detail

CronWorkflow

protected CronWorkflow(String type,
                       WorkflowSettings settings)

Extend cron workflow definition with customized workflow settings. It is recommended to enable the workflow state and action history cleanup. Extending class must implement the 'doWork` state method. For example:

 public NextAction doWork(StateExecution execution) {
   // do the work here
   return NextAction.moveToState(schedule, "Work done");
 }
 

Parameters:

type - The type of the workflow.

settings - The workflow settings.

CronWorkflow

protected CronWorkflow(String type)

Extend cron workflow definition. Uses workflow settings that enable automatic workflow state and action history cleanup (delete history older than 45 days, run cleanup once per day). Extending class must implement the 'doWork` state method. For example:

 public NextAction doWork(StateExecution execution) {
   // do the work here
   if (rescheduleImmediately) {
     return NextAction.moveToState(schedule, "Work done");
   }
   return NextAction.moveToStateAfter(waitForWorkToFinish, DateTime.now().plusHours(hoursToWait), "Waiting for work to finish");
 }
 

Parameters:

type - The type of the workflow.

Method Detail

schedule

public NextAction schedule(StateExecution execution,
                           String cron)

Determines the next execution time for the doWork state by calling getNextActivationTime.

Parameters:

execution - The workflow execution context.

cron - The cron state variable.

Returns:

Action to go to doWork state at scheduled time.

getNextActivationTime

protected org.joda.time.DateTime getNextActivationTime(StateExecution execution,
                                                       String cron)

Calculates next activation time based on cron state variable. Override for custom scheduling.

Parameters:

execution - The workflow execution context.

cron - The cron schedule.

Returns:

The next activation time.

handleFailure

public NextAction handleFailure(StateExecution execution)

Tries to handle failures by calling handleFailureImpl(io.nflow.engine.workflow.definition.StateExecution).

Parameters:

execution - The workflow execution context.

Returns:

Action to go to schedule or failed state.

handleFailureImpl

protected boolean handleFailureImpl(StateExecution execution)

Logs an error and continues. Override for custom error handling.

Parameters:

execution - The workflow execution context.

Returns:

True if workflow should be rescheduled. False to go to failed state and wait for manual actions.

waitForWorkToFinish

public NextAction waitForWorkToFinish(StateExecution execution)

Calls waitForWorkToFinishImpl(io.nflow.engine.workflow.definition.StateExecution) to check if this instance should wait for work to finish or move to schedule state.

Parameters:

execution - The workflow execution context.

Returns:

Action to retry later or move to schedule state.

waitForWorkToFinishImpl

protected org.joda.time.DateTime waitForWorkToFinishImpl(StateExecution execution)

Returns null to move to schedule state immediately if there are no incompleted child workflows, or current time plus 1 hour to check again later. Override for custom logic.

Parameters:

execution - The workflow execution context.

Returns:

Time when check should be retried. Null to go to schedule state immediately.