Chapter 21. JBoss Developer Studio

Procedure 21.1. Task

1. Create a new session in JBoss Rules.
2. Select Window Preferences. A "Preferences" dialog will appear.
3. On the left side of this dialog, under the JBoss Rules category, select "Installed JBoss Rules runtimes". The panel on the right should then show the currently defined JBoss Rules runtimes.
4. Click on the add button. A dialog will pop up asking for the name of your runtime and the location on your file system where it can be found.
5. To use the default jar files from the JBoss Rules Eclipse plugin, create a new JBoss Rules runtime automatically by clicking the Create a new Drools 5 runtime ... button. A file browser will appear, asking you to select the folder on your file system where you want this runtime to be created. The plugin will then automatically copy all required dependencies to the specified folder.
6. To use one specific release of the JBoss Rules project, create a folder on your file system that contains all the necessary JBoss Rules libraries and dependencies. Give your runtime a name and select the location of this folder containing all the required jars. Click OK.
7. The runtime will appear in your table of installed JBoss Rules runtimes. Click on checkbox in front of the newly created runtime to make it the default JBoss Rules runtime. The default JBoss Rules runtime will be used as the runtime of all your JBoss Rules projects that have not selected a project-specific runtime.
8. Restart Eclipse if you changed the default runtime and you want to make sure that all the projects that are using the default runtime update their classpath accordingly.

Procedure 21.2. Task

1. Use the New JBoss Rules Project wizard to create a new JBoss Rules Project.
2. Alternatively, convert an existing Java project to a JBoss Rules project using the action by right-clicking on a Java object then clicking the Convert to JBoss Rules Project dialogue. The plugin will automatically add all the required jars to the classpath of your project.
3. Optionally, on the last page of the New JBoss Rules Project wizard you can choose to have a project-specific runtime. Uncheck the Use default JBoss Rules runtime checkbox and select the appropriate runtime in the drop-down box.
4. To access the preferences and add runtimes, go to the workspace preferences and click Configure workspace settings ....
5. You can change the runtime of a JBoss Rules project at any time by opening the project properties and selecting the JBoss Rules category. Mark the Enable project specific settings checkbox and select the appropriate runtime from the drop-down box.
6. Click the Configure workspace settings ... link. This opens the workspace preferences showing the currently installed runtimes. Use the menu to add new runtimes in this space. If you deselect the Enable project specific settings checkbox, it will use the default runtime as defined in your global preferences.

Procedure 21.3. Task

1. Create an empty text .drl file.
2. Copy and paste your rule into it.
3. Save and exit.
4. Alternatively, use the Rules Wizard to create a rule but pressing Ctrl+N or by choosing it from the toolbar.
5. The wizard will ask for some basic options for generating a rule resource. For storing rule files you would typically create a directory src/rules and create suitably named subdirectories. The package name is mandatory, and is similar to a package name in Java. (That is, it establishes a namespace for grouping related rules.)
6. Select the options that suit you and click Finish.

Procedure 21.4. Task

1. To be able to use JBoss Rules views, create breakpoints in your code by invoking the working memory. For example, the line where you call workingMemory.fireAllRules() is an ideal place to place a break.
2. If the debugger halts at a joinpoint, select the working memory variable in the debug variables view. The available views can then be used to show the details of the selected working memory.

Procedure 21.5. Task

1. To create an audit log, execute the rules engine. You will be given the option of creating a new audit log.
2. Enter the following code:

   StatefulKnowledgeSession ksession = kbase.newStatefulKnowledgeSession();
   // Create a new Knowledge Runtime Logger, that logs to file.
   // An event.log file is created in the subdirectory log dir (which must exist) of the working directory
   KnowledgeRuntimeLogger logger = KnowledgeRuntimeLoggerFactory.newFileLogger( ksession, "log/event");
   
   ksession.insert(...);
   ksession.fireAllRules();
   
   // stop logging
   logger.close();

3. Open the log by clicking the Open Log action, the first icon in the Audit View, and select the file. The Audit View now shows all events that where logged during the executing of the rules.

Procedure 21.6. Task

1. Open the DSL editor and select the mapping tab.
2. Select a mapping item (a row in the table) to see the expression and mapping in the text fields below the table.
3. Double click or press the edit button to open the edit dialog.
4. Other buttons let you remove and add mappings. Don't remove mappings while they are still in use.

Procedure 21.7. Task

1. To create breakpoints for easier debugging of rules, open the DRL editor and load the DRL file you wish to use.
2. Double-click the ruler of the DRL editor at the line where you want to add a breakpoint. Note that rule breakpoints can only be created in the consequence of a rule. Double-clicking on a line where no breakpoint is allowed will do nothing. A breakpoint can be removed by double-clicking the ruler once more.
3. Right-click the ruler. A popup menu will show up, containing the Toggle breakpoint action. Note that rule breakpoints can only be created in the consequence of a rule. The action is automatically disabled if no rule breakpoint is allowed at that line.
4. Click the action to add a breakpoint at the selected line, or remove it if there was one already.

   Note

   The Debug Perspective contains a Breakpoints view which can be used to see all defined breakpoints, get their properties, enable/disable or remove them, and so on.

Procedure 21.8. Task

1. Open the DRL Editor.
2. Select the main class of your application.
3. Right-click on it and select the Debug As > sub-menu and select JBoss Rules Application.
   Alternatively, you can also select the Debug ... menu item to open a new dialog for creating, managing and running debug configurations.
4. Select the Drools Application item in the left tree and click the New launch configuration button (leftmost icon in the toolbar above the tree). This will create a new configuration with some of the properties already filled in based on the main class you selected in the beginning.
5. Change the name of your debug configuration to something meaningful. You can accept the defaults for all other properties.
6. Click the Debug button on the bottom to start debugging your application. You only have to define your debug configuration once. The next time you run your JBoss Rules application, you can select the previously defined configuration in the tree as a sub-element of the JBoss Rules tree node, and then click the JBoss Rules button. The Eclipse toolbar also contains shortcut buttons to quickly re-execute one of your previous configurations.