bpmn-instanes

Instances management for cquencial:bpmn-engine. This extension allows you to easily access (and thus manage) running process instances.

Installation

Add this package with cquencial:bpmn-engine to your packages list (if you didn't already install cquencial:bpmn-engine):

meteor add cquencial:bpmn-engine cquencial:bpmn-instances

How it works

If the extension is active each new created process instance (new Bpmn.Engine) will receive a unique instanceId (which is also a relevant part of other extensions). A document, keeping this instanceId is created and added to the Bpmn.instances.collection Collection. By the same id a reference to the instance is added to a cache dictionary.

You can create subscribe to the collection and therefore let your client's manage the instances. See the example project for some use cases.

If a process ends, is stopped or cancelled or the server restarts, the reference and the document are removed from the cache / the collection.

Usage

The extension is off by default. To activate it, you need to switch the extension to on in your server environment. Note, that the extension is not to be imported by itself but decorated to the Bpmn class/object.

import { Bpmn } from 'cquencial:bpmn-engine';

Bpmn.instances.on();

This activates the extension to listen to every possible BPMN process state change and creates a new persistence state, that is saved to the collection.

If you want to extension to be off just call

Bpmn.instances.off();

API

The extension provides some methods to manage the instances manually and which are also used internally.

Currently the functionality works only without problems on the server.

Bpmn.instances.get( instanceId )

Returns a process instance (created by new Bpmn.Engine ) that is stored in the cache. Returns undefined if the cache has no instance referenced by the given indtanceId.

Bpmn.instances.size()

Returns the size of the cache object / the number of cached process instances.

Bpmn.instances.has( instanceId )

Returns true if an instance is cached by the given instanceId and if the collection has a document with that id. Otherwise returns false.

Bpmn.instances.add({ instanceId, engine })

Adds an existing engine (process instance) to the collection and cache by a given instanceId. Usually it is the engine.instanceId property but this way it allows you to alternatively use custom ids (like uuid).

Bpmn.instances.remove({ instanceId })

Removes an engine from collection / cache by given instanceId

Collection

The extension ships with a Mongo.Collection and a caching dictionary by default. The collection and the cache are deleted on each server restart (because the running process instances will also be wiped from memory and thus all instance reeferences will be null pointers).

If you want to keep your instances persistent you may check out cquencial:bpmn-persistence.