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== Introduction == We want to give to JWT the ability to monitor workflow engines (ie AgilPro, Bonita...) at thein runtime; to give the user the ability to check the state of a workflow from Eclipse. == Ideas == * We think that "monitoring a workflow" is a synonymous for "getting full workflow state" * To define a workflow state, we need a generic API to define a workflow. This API must fit with most of workflow engines. * The monitoring tool must be able to support several workflow engines, and several ways to access them (WebService, RMI, ...) == Workflow State Model == * Workflow Engine ** Process(*) *** name(1) ''String'' *** Project(1) **** name(1) ''String'' **** version(0..1) ''String'' **** properties(*) ***** name(1) ''String'' ***** value(1) ''String'' *** Activity(1) **** name(1) ''String'' **** state(1) ''String'' **** properties(*) ***** name(1) ''String'' ***** value(1) ''String'' == Concretely == * As this work has been done in the context of SCorWare SCA project, first implementation is done with the aim of monitoring a Workflow Engine (Bonita) through WebServices. SCorWare uses CXF webservice engine, with Aegis databinding. That is the only technologies that are currently supported. * However, we made some efforts to make the architecture extensible enough to handle other bindings; so that it might be easy to add a support for RMI, or an Eclipse internal Workflow Engine (eg MWE) or anything else. This is made by using extension points. == How do I monitor another workflow engine over another binding with this plugin? == # Implement an interface (WorkflowService) with your favorite workflow engine. (We use the "Adapter" design-pattern) # Make this service accessible to the user who wants to monitor it in Eclipse (you can use webservices, rmi, or anything you are able to write a client programmaticaly) # Implement an extension plug-in which defines the way to access the service (so called a service provider) from inside Eclipse. == Screenshot == These are a screenshot of what we currently have. Obviously, it can be improved... [[Image:jwt_monitor1.jpg|500px]] [[Image:jwt_monitor2.jpg|500px]] [[Image:jwt_monitor3.jpg|500px]] [[Image:jwt_monitor4.jpg|500px]] [[Image:jwt_monitor5.jpg|500px]] == Implementation == === General Schema === [[Image:jwt_monitoring.jpg]] === Comments === * The UI is implemented as an Eclipse View * The view uses the interface WorkflowService, and creates the tree wih the beans that WorkflowService methods provide. Those beans are then embedded in a composite pattern, to fit with TreeViewer requirements. * The interface WorkflowService is an adapter. Each workflow engine that is to be supported in JWT must implement this interface according to its own specifications. * When accessing a Workflow Service, the plug-in calls a method from a plug-in linked to the base plug-in through extension point. This extension provides an implementation for the interface WorkflowServiceProvider, and more specifically for its "processServiceAdd" method. * This way, we can consider that we have one plug-in per binding. (That's why SCA could be useful => One plug-in for several bindings) === Code === WorkflowService API: <source lang="java"> package org.eclipse.jwt.runtime.workflow; import org.eclipse.jwt.runtime.workflow.bean.Activity; import org.eclipse.jwt.runtime.workflow.bean.Process; import org.eclipse.jwt.runtime.workflow.bean.Processes; import org.eclipse.jwt.runtime.workflow.bean.Project; import org.eclipse.jwt.runtime.workflow.bean.Projects; /** * @author gdecarnin * * NB. These methods do not "officially" throw BonitaServerException because * it will rather result in an UndeclaredThrowableException in a ws client. */ public interface WorkflowService { public Projects listProjects(boolean returnProperties, boolean startableOnly, String login); public Project getProjectProperties(Project project, String login); public Process instanciateProject(Process process, String login); public Processes listUserActivities(boolean returnProperties, boolean returnTerminated, String login); public Process startActivity(Process process, String login); public Activity getActivityProperties(Process process, String login); public Activity setActivityProperties(Process process, String login); public Process terminateActivity(Process process, String login); } </source> == With SCA == * SCA is aimed to make binding between several components (eg a Workflow Engine that promotes a service to monitor it, and a client to this service that monitor it in another application...) become more abstract. When possible, we could use SCA to manage theses bindings in JWT. * We could provide a composite generator binary (for SCA) in the base plugin. This is possible by adding a binary without problem of license (see java2wsdl binary in STP), so that it could be part of an official release.

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