Re: Workflow in Database

I implemented the JDBCWorkflowFactory, and it seems to work ;-)
Ok, how does it work:
At the moment it uses one table with 2 fields (WF_NAME; WF_DEFINITION)
the first contains the name of the workflow and the second contains
the whole workflow definition xml as a blob.

problems:
1. osworkflow doesn't correctly encode strings in xml,
if you have && in a beanshell script it'll just write it down like that,
instead of escaping it. (e.g. with CDATA) (--> see jira bug WF-152)
this causes problems when you try to save the example workflow into
database.
2. patch for ConfigLoader required:
persistence properties must be loaded before the JDBCWorkflowFactory is initialized,
because I load the DB settings from the persistence properties.
I could change it to load the setting from a property in the factory section of osworkflow.xml,
but this would just create yet another place where you have to set the datasource. :-(

If nobody disagrees, I'll put this patch and JDBCWorkflowFactory.java in jira.

philipp

Index: java/com/opensymphony/workflow/config/ConfigLoader.java
===================================================================
RCS file:
/cvs/apps/flow/opensymphony/osworkflow/src/java/com/opensymphony/workflow/config/ConfigLoader.java,v
retrieving revision 1.2
diff -r1.2 ConfigLoader.java
77a78,87
> persistence = p.getAttribute("class");
>
> NodeList args = p.getElementsByTagName("property");
> persistenceArgs = new HashMap();
>
> for (int i = 0; i < args.getLength(); i++) {
> Element e = (Element) args.item(i);
> persistenceArgs.put(e.getAttribute("key"), e.getAttribute("value"));
> }
>
98,107d107
< }
<
< persistence = p.getAttribute("class");
<
< NodeList args = p.getElementsByTagName("property");
< persistenceArgs = new HashMap();
<
< for (int i = 0; i < args.getLength(); i++) {
< Element e = (Element) args.item(i);
< persistenceArgs.put(e.getAttribute("key"), e.getAttribute("value"));


----- Original Message ----- 
From: "Hani Suleiman" <[email protected]>
To: <[email protected]>
Sent: Thursday, May 01, 2003 6:15 PM
Subject: Re: [Opensymphony-developers] Workflow in Database


> I've added the load(InputStream) method, it's in CVS now.
>
> For the other issue, I don't think it's a good idea to add that. The
> reason is that the way it is set up currently, the save method is free
> to choose any way of saving. It doesn't need to store it as an xml file
> either. It could persist the workflow descriptor to a set of database
> tables which model its structure, or to a swing JTree model.
>
> The WorkflowLoader is a convenience class, and so I don't think it's
> such a big deal to duplicate the small amount of code it is to write
> out the xml file. You could always have your jdbc factory subclass
> XMLWorkflowFactory, and use its writing method. Okok, so this wasn't
> possible before, but I just fixed it in XMLWorkflowFactory.
>
> You can subclass it (JDBCXMLWorkflowFactory) and override the
> saveWorkflow method, then use the writeXML method to write out your
> workflow to whatever Writer you want.
>
> Let me know if you have any problems with your implementation!
>
> Hani
>
> On Thursday, May 1, 2003, at 10:03 AM, Philipp Hug wrote:
>
> > I wrote a class to put workflow definitions in a JDBC database,
> > but I need some patches in osWorkflow to prevent code duplication:
> >
> > 1. WorkflowLoader.java
> > --> add an additional load method that takes an InputStream instead of
> > an
> > URL
> >     /**
> >      * Load a workflow descriptor from a URL
> >      */
> >     public static WorkflowDescriptor load(final URL url) throws
> > SAXException, IOException {
> >         return load(url.openStream());
> >     }
> >
> >     /**
> >      * Load a workflow descriptor from an InputStream
> >      */
> >     public static WorkflowDescriptor load(final InputStream is) throws
> > SAXException, IOException {
> > ----
> >
> > 2. Move save() code from XMLWorkflowFactory into a new class similar to
> > WorkflowLoader, otherwise the code
> > would need to be duplicated. It's just a small part of code but anyway:
> >
> > the code could look like that:
> > public static save(OutputStream os) {
> >         Writer out = new OutputStreamWriter(os);
> >
> >         PrintWriter writer = new PrintWriter(new BufferedWriter(out));
> >         writer.println("<?xml version=\"1.0\" encoding=\"UTF-8\"?>");
> >
> >         writer.println("<!DOCTYPE workflow PUBLIC \"-//OpenSymphony
> > Group//DTD OSWorkflow 2.5//EN\"
> > \"http://www.opensymphony.com/osworkflow/workflow.dtd\">");
> >         descriptor.writeXML(writer, 0);
> >         writer.flush();
> >         writer.close();
> > }
> >
> > What do you think? Should I submit a feature request/bug in JIRA?
> >
> > philipp
> >
> >
> >
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>
>
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