This section covers the technical aspects of Guvnor, it is not necessary to use this if you are integrating or an end user of the application. However, Drools is open source, so build instructions form part of the manual.
You may want to build from source if you want to re-use components, or embed the application within another.
The above diagram shows the major components of the system and how they integrate and are deployed. The User Guide has more details on the parts that are highly configurable (e.g. database).
Guvnor is deployed as a WAR, which provides user interfaces over the web, and provides binary packages using URLs (or files). It uses the JSR-170 standard for data storage (JCR). JBoss Seam is used as the component framework, and GWT is used as the widget toolkit for constructing the AJAX-based web user interface.
This section will go over the steps necessary to build various components. Mostly this is automated, but the manual process is described for thoroughness.
There are 2 modules: guvnor-repository (back end) and
guvnor-webapp (front end and rules integration). The
guvnor-webapp module depends on the guvnor-repository module, as
well as other components. Guvnor is part of the main build for all of Drools - when building Drools, Guvnor is
built alongside it.
Maven 2 is used as the build system. To get started, the whole of the source tree for JBoss Rules needs to be checked out. This includes the other modules, and the top level lib and repository directories (which are needed by the build); as the Guvnor build is part of the main Drools build.
Initially, go into the root of the jboss-rules checked out source tree, and run mvn
install to install all the components for the inter-project dependencies. If the build is broken (all
care is taken for this eventuality not to occur), the flag -DskipTests can be used to prevent
failing unit tests from preventing the build.
When wishing to build Guvnor, go into the guvnor-webapp directory, and run mvn package.
This will run the tests, and then build a deployable WAR. Once the WAR file is in the target directory, the Guvnor
is ready to go.
The GUI widgets for the web front end are developed with GWT (Google Web Toolkit).
Each module has a ready to go and up to date eclipse project configuration, so they can merely be imported
into the eclipse workspace. These projects are generated by Maven. Use the mvn eclipse:eclipse
command to refresh them in case they are wrong or outdated. They have been manually modified to have project
dependencies which means that the code can be stepped through when debugging.
Some environment variables are required in eclipse (for Window: >Preferences->Java->Build
path-> Classpath variables): the M2_REPO, as normal, to point to where Maven downloads
shared dependencies. GWT_HOME should point to where you installed GWT. GWT_DEV must
point to the platform specific "dev" JAR that ships with the version of GWT you have.
How to launch from Eclipse: unit tests can be launched, as normal (in which case only M2_REPO
setup is needed, GWT does not need to be downloaded separately), or it can be launched it in hosted
mode using the GWT browser, which is great for debugging (from GUI to back end, the code can be stepped
through, and changes made on the fly and simply hit refresh). There is a Guvnor.launch file
in in the guvnor-webapp directory. To launch Guvnor in debug mode, open the Run dialog
(->), and then choose
from the list. Launching this will open a new window, with Guvnor in debug mode, ready to go.
Downloading and debugging Guvnor with GWT is optional, so if there are no GUI issues being worked on then this step can be safely skipped.
Guvnor uses a service interface to separate the GUI from the back end functionality. In this case the back end
both includes the asset repository (guvnor-repository and JCR) as well as the compiler
specifics to deal with rules.
The main interface is RepositoryService, which is implemented in
ServiceImplementation. The GWT ajax front end talks to this interface using the asynchronous callback
mechanism that GWT uses. The Seam configuration file is beans.xml. Refer to the Seam
documentation, and the beans.xml file for details.
This service interface may be re-used by alternative components or front ends.
The GWT user interface may be re-used, as it is GWT is only one html page:
Guvnor.html.
Normally Guvnor is intended to be deployed as its own WAR, however it can be combined with another application (with some care), but it is easier to keep it as a separate WAR. We recommend deploying Guvnor by itself because this will make it easier to upgrade to newer releases as they come out.
The Guvnor.html file can be customized. For example to change logos or embed Guvnor in
another page. Take a look at the Guvnor.html file for details.
Refer to Chapter 12, Database configuration for for configuration options for database and filesystems.
Versions of assets are stored in the database along with the data.
When snapshots are created, copies are made of the entire package into a separate location in the JCR database.
For those familiar with JCR and Apache Jackrabbit, the *.cnd files are in the source for
the node type definitions as some wish to view these. In a nutshell, a package is a folder and
each asset is a file: an asset can either be textual or have a binary attachment.
As an open source project, contributions from the wider community are encouraged. In order to contribute consult the wiki and project home pages. A useful way to contribute is via logging issues or feature requests in JIRA. This is JIRA link to use.