net.corda.core.utilities / ProgressTracker

ProgressTracker

class ProgressTracker

A progress tracker helps surface information about the progress of an operation to a user interface or API of some kind. It lets you define a set of steps that represent an operation. A step is represented by an object (typically a singleton).

Steps may logically be children of other steps, which models the case where a large top level operation involves sub-operations which may also have a notion of progress. If a step has children, then the tracker will report the steps children as the "next step" after the parent. In other words, a parent step is considered to involve actual reportable work and is a thing. If the parent step simply groups other steps, then youll have to step over it manually.

Each step has a label. It is assumed by default that the label does not change. If you want a label to change, then you can emit a ProgressTracker.Change.Rendering object on the ProgressTracker.Step.changes observable stream after it changes. That object will propagate through to the top level trackers changes stream, which renderers can subscribe to in order to learn about progress.

An operation can move both forwards and backwards through steps, thus, a ProgressTracker can represent operations that include loops.

A progress tracker is not thread safe. You may move events from the thread making progress to another thread by using the Observable subscribeOn call.





Types

Change sealed class Change
DONE object DONE : Step
RelabelableStep inner class RelabelableStep : Step

This class makes it easier to relabel a step on the fly, to provide transient information.

Step class Step

The superclass of all step objects.

UNSTARTED object UNSTARTED : Step

Constructors

<init> ProgressTracker(vararg steps: Step)

A progress tracker helps surface information about the progress of an operation to a user interface or API of some kind. It lets you define a set of steps that represent an operation. A step is represented by an object (typically a singleton).

Properties

allSteps val allSteps: List<<ERROR CLASS><Int, Step>>

A list of all steps in this ProgressTracker and the children, with the indent level provided starting at zero. Note that UNSTARTED is never counted, and DONE is only counted at the calling level.

changes val changes: <ERROR CLASS><Change>

An observable stream of changes: includes child steps, resets and any changes emitted by individual steps (e.g. if a step changed its label or rendering).

currentStep var currentStep: Step

Reading returns the value of stepsstepIndex, writing moves the position of the current tracker. Once moved to the DONE state, this tracker is finished and the current step cannot be moved again.

currentStepRecursive val currentStepRecursive: Step

Returns the current step, descending into children to find the deepest step we are up to.

parent var parent: ProgressTracker?

The parent of this tracker: set automatically by the parent when a tracker is added as a child

stepIndex var stepIndex: Int

The zero-based index of the current step in the steps array (i.e. with UNSTARTED and DONE)

steps val steps: Array<Step>

The steps in this tracker, same as the steps passed to the constructor but with UNSTARTED and DONE inserted.

topLevelTracker val topLevelTracker: ProgressTracker

Functions

getChildProgressTracker fun getChildProgressTracker(step: Step): ProgressTracker?
nextStep fun nextStep(): Step

Iterates the progress tracker. If the current step has a child, the child is iterated instead (recursively). Returns the latest step at the bottom of the step tree.

setChildProgressTracker fun setChildProgressTracker(step: Step, childProgressTracker: ProgressTracker): Unit