Package org.jenkinsci.plugins.workflow.steps

Class SynchronousNonBlockingStepExecution<T>

java.lang.Object

org.jenkinsci.plugins.workflow.steps.StepExecution

org.jenkinsci.plugins.workflow.steps.SynchronousNonBlockingStepExecution<T>

Type Parameters:

T - the type of the return value (may be Void)

All Implemented Interfaces:

Serializable

public abstract class SynchronousNonBlockingStepExecution<T>
extends StepExecution

Similar to SynchronousStepExecution (it executes synchronously too) but it does not block the CPS VM thread.

See Also:

StepExecution, Serialized Form

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	SynchronousNonBlockingStepExecution(StepContext context)

Method Summary

Modifier and Type	Method	Description
boolean	blocksRestart()	Allows a step to indicate that AsynchronousExecution.blocksRestart() should be true.
String	getStatus()	May be overridden to provide specific information about what a step is currently doing, for diagnostic purposes.
void	onResume()	Called when StepExecution is brought back into memory after restart.
protected abstract T	run()	Meat of the execution.
boolean	start()	Start execution of something and report the end result back to the given callback.
void	stop(Throwable cause)	If the computation is going synchronously, try to cancel that.

Methods inherited from class org.jenkinsci.plugins.workflow.steps.StepExecution

applyAll, applyAll, getContext, getStatusBounded

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SynchronousNonBlockingStepExecution

protected SynchronousNonBlockingStepExecution(@NonNull
                                              StepContext context)

Method Detail

run

protected abstract T run()
                  throws Exception

Meat of the execution. When this method returns, a step execution is over.

Throws:

Exception

start

public final boolean start()
                    throws Exception

Description copied from class: StepExecution

Start execution of something and report the end result back to the given callback.

Arguments are passed when instantiating steps.

This method will run in the CPS VM thread and as such should not perform I/O or block. Use SynchronousNonBlockingStepExecution or GeneralNonBlockingStepExecution as needed.

Specified by:

start in class StepExecution

Returns:

true if the execution of this step has synchronously completed before this method returns. It is the callee's responsibility to set the return value via StepContext.onSuccess(Object) or FutureCallback.onFailure(Throwable). false if the asynchronous execution has started and that StepContext will be notified when the result comes in. (Note that the nature of asynchrony is such that it is possible for the StepContext to be already notified before this method returns.)

Throws:

Exception - if any exception is thrown, Step is assumed to have completed abnormally synchronously (as if FutureCallback.onFailure(java.lang.Throwable) is called and the method returned true.)

stop

public void stop(Throwable cause)
          throws Exception

If the computation is going synchronously, try to cancel that.

Overrides:

stop in class StepExecution

Parameters:

cause - Contextual information that lets the step know what resulted in stopping an executing step, passed in the hope that this will assist diagnostics.

Throws:

Exception

onResume

public void onResume()

Description copied from class: StepExecution

Called when StepExecution is brought back into memory after restart. Convenient for re-establishing the polling.

Currently not permitted to throw exceptions, but may report errors via FutureCallback.onFailure(java.lang.Throwable).

Overrides:

onResume in class StepExecution

See Also:

SynchronousResumeNotSupportedException

getStatus

@NonNull
public String getStatus()

Description copied from class: StepExecution

May be overridden to provide specific information about what a step is currently doing, for diagnostic purposes. Typical format should be a short, lowercase phrase. It should not be localized as this is intended for use by developers as well as users. May include technical details about Jenkins internals if relevant.

Overrides:

getStatus in class StepExecution

Returns:

current status, or null if unimplemented

See Also:

StepExecution.getStatusBounded(long, java.util.concurrent.TimeUnit)

blocksRestart

public boolean blocksRestart()

Description copied from class: StepExecution

Allows a step to indicate that AsynchronousExecution.blocksRestart() should be true. Typically this would be true if StepExecution.getStatus() indicates that the step is in the middle of something active, as opposed to waiting for an external event or a body to complete.

Note that activity in the CPS VM thread automatically blocks restart, so overriding this is only necessary for steps using a background thread, such as SynchronousNonBlockingStepExecution or GeneralNonBlockingStepExecution.

Overrides:

blocksRestart in class StepExecution

Returns:

false by default