topic Re: Migrating example source code from the Manning book in Alfresco Archive

Migrating example source code from the Manning book

jemmerling — Thu, 04 Jun 2015 02:32:42 GMT

If anyone is interested, I migrated the source code examples from the Manning book to the latest version of Activiti (5.17.0).First thing to be aware of is the installation process described in the book has been phased out, see http://bpmn20inaction.blogspot.nl/2013/02/activiti-in-action-updates-par

Re: Migrating example source code from the Manning book

jemmerling — Thu, 11 Jun 2015 23:00:50 GMT

Some updates having to do with database access. First I must confess I don't understand everything that is going on.

So the Activiti Explorer has a db.properties containing the following:

jdbc.url=jdbc:h2:mem:activiti;DB_CLOSE_DELAY=1000.

This implies an in-memory database. For the examples in the book to work i.e. the Book Order example in Chapter 1, it seems it should be using the stand-alone H2 instance as called for in the book.

Another thing I noticed is that in my home directory there was a couple of H2 database files including one named activiti.h2.db. I'm not certain how that got created (would an in-memory instance do that?). Also, when the Explorer launches it tries to create a new Activiti schema which makes sense for an in-memory database.

What I changed was to get everything to use the following URL: jdbc:h2:~/activiti this includes the Explorer and the Manning book example code. I was finally able to get the example to work! I can now see the new task in the Explorer. It did seem rather slow showing up, though.

However under the circumstances I am not convinced that if I were to bounce Tomcat there would not be a problem because some of my experimentation indicated it was failing startup due to trying to create a new schema instance where one already exists. Which makes sense for an in-memory H2 instance but not for a stand-alone instance, however the example in the book seems to require a stand-alone instance.

Just wondering if anybody has further insight?

Re: Migrating example source code from the Manning book

jbarrez — Fri, 12 Jun 2015 10:25:30 GMT

The book assumes an H2 database exposed to TCP I would assume.
This is an in memory database, but persistent in a file, so it would survive a reboot.

Re: Migrating example source code from the Manning book

jemmerling — Sat, 13 Jun 2015 14:14:22 GMT

1.) Can an in-memory H2 instance be accessed from a different JVM e.g. the Explorer data being accessed by the JUnit tests in the Manning book sample code? As that is needed for the examples to work.
2.) If the data is persisted between sessions then won't there still be a problem when Tomcat is bounced because the Explorer will try to recreate the schema from scratch?

Thanks!

–John Emmerling

Re: Migrating example source code from the Manning book

jbarrez — Tue, 16 Jun 2015 09:09:21 GMT

1. Yes, if you set up the H2 db with the TCP interface

2. No, there is a check in Activiti that checks if the schema is correct. Unless you mean something else with 'bounced'?