Author: rsoika

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RELEASE 3.0 STARTED

We are now starting the next release of the Imixs Workflow 3.0

See: http://java.net/jira/browse/IMIXS_WORKFLOW-90

The general idea behind the new 3.0 release was to make use of the new EJB 3.1 container features. Because the current Imxis EntityServiceBean is in some methodes a little bit deprecated. One reason was the early implementation in the beginning of JEE5. The JPA methods are optimized for Toplink Driver which is no longer supported. So its time to make an Update!

General requirements for the new Workfow Engine

  • Replace the Entity Bean based on ItemCollection with a Map Interface
  • Use of EJB 3.1 features (JPA Map Feature)
  • Simplify the packaging (Light EJB API)
  • Optimize Scheduler Feature (persist settings in a entity)
  • No changes to the Workflow Service API – to make migration easy

Migration

A Migration is necessary as one of the main goals is to pesist no longer the ItemCollection Object but a simple portable Map Interface.
So we need a way to migrate application from Version 2.x to 3.0. As we learned in migrations from 1.x to 2.x this is not an easy work.
The goal of the new migration strategy must be a background migration.
So a tool should migrate workitems from a old datastorage into a new one running independed of a productive workflow app. This can be done by monitoring the $modified timestamp. As we know most of the data will not be changed during migration this can be done easily .

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IMIXS WORKFLOW – REPORT GENERATOR FOR PDF

With the latest version of Imixs Workflow now business reports can be created in a lot of different output formats like PDF, MS Excel, MS Word or any other XSL Transformation. Read more about the Imixs Workflow REST Interface and how it works.

http://www.imixs.org/xml/restservice.html

Imixs Workflow did not only empower you in building bpm solutions based on the JEE plattform. It also gives you a flexible architecture to fulfill business requirements like compliance features, creation of business reports and securing confidential business data in a fast and easy way.

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WHY ARE CHANGING THE REQUIREMENTS IN A SOFTWARE PROJECT SO OFTEN?

For several years I have developed even business applications for small, medium and large organizations. Actually, I should have learned a lot about what customers need. But like most software developers I am always surprised about endless changes during the project. You start a new software project but when you are approaching the end your customers have new ideas. Why is that? Continue reading “WHY ARE CHANGING THE REQUIREMENTS IN A SOFTWARE PROJECT SO OFTEN?”
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JPA – WORKING WITH GENERIC VALUE OBJECTS

Working with generic value objects and jpa is shown by the implementation of the ImixsEntityService EJB. This service ejb is provided by the Imixs Workflow Project. It can be used to store objects independent from a specific Entity Bean. Also queries with JPQL are possible.
See: http://www.imixs.org/jee/examples/entityservice.html
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IMIXS ADMIN CLIENT 2.1.1

The latest version of the Imixs Admin Client is finally released. TheImixs Admin Client is a Web Application which allows you to administrate a Imixs JEE Workflow Instance. The Admin Client can be deployed on any JEE Server independent from a workflow Application. So the Imixs Admin Client can be used to adminstrate different instances of the Imixs JEE Workflow Implemenation on the same JEE Application Server.

Downloadpage

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HIDING ACTIVIES FROM USER

Today I stumbled into an issue with hidden workflow activities. Normally you can simple hide an activity to unauthorized users by adding an application specific access role to the property section ‘Visiblity and Access’. For example you can add the role ‘org.imixs.ACCESSLEVEL.MANAGERACCESS’ to allow only Managers to use this workflow activity.

But this seems not to work. The reason is that the Imixs Modeler stores the read-access restriction into the property ‘namReaders’. And this is no read-access property per default. Only the property ‘$readAccess’ will be recognized by the workflow system to protect workitems.

But the solution is quite simple. You only need to add the field name to the Imixs EntityService Bean declaration from the ejb-jar.xml descriptor:

            <ejb-name>EntityServiceBean</ejb-name>
            <ejb-class>org.imixs.workflow.jee.ejb.EntityServiceBean</ejb-class>
            <session-type>Stateless</session-type>
            <env-entry>
                <description>Additional Reader Field for Workflow Model</description>
                <env-entry-name>READ_ACCESS_FIELDS</env-entry-name>
                <env-entry-type>java.lang.String</env-entry-type>
                <env-entry-value>namreaders</env-entry-value>
            </env-entry>            
        </session>

No the property ‘namReaders’ is treated by the Imixs Workflow System as a reader field.

I think we will change the Imixs Modeler in the next release to support also the default field ‘$readAccess’. So no further configuration will be necesary here.

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MYSQL AND BLOB FIELD SIZE

Using the Imixs Workflow together with mysql can lead into a problem with large data stored in a single workitem. The Database schema use by the Imixs Workflow will be generated automatically by the OR-Mapper (e.g. Toplink, Eclipslink). This is all done well. But the Data table ‘EntityData’ used by the Imixs Workflow engine contains the column ‘itemcollection’. This column will store all undstuctured data. And in some cases this data can become very large. For example when storing a attachment into a workitem the field can be serveral MB in size. The default field type in mysql is ‘BLOB’. And this fieldtype is restricted to a maximum size of 64KB. So the Imixs workflow engine can not store large workitems. This will result into a SQL Execption.

To avoid this problem the Datatype can be changed from ‘BLOB’ to ‘MEDIUMBLOB’ (=16MB) or ‘LONGBLOB’ (=4GB). This can be done with the MySQL Admin Client or from the MySQL command line.

ALTER TABLE <Tabellenname> CHANGE <columnname> <columnname> LONGBLOB;

To change the datatype for a example database ‘imixsdb’ use the following command:

ALTER TABLE ENTITYDATA CHANGE ITEMCOLLECTION ITEMCOLLECTION LONGBLOB;

 

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