JWT Extensions

This page provides information on how to extend the JWT Workflow Editor (JWT-WE).

Overview

The JWT Workflow Editor defines several extension points and mechanisms that allow users to customize and extend the abilities and properties of JWT-WE without changing the editor itself. However, there may be cases in which it becomes necessary to alter the Workflow Editor code itself, notably when the new features need to be implemented by committers of the JWT project. This page is intended to describe how third party suppliers can extend JWT-WE (e.g. with custom views on the model elements) through external plugins using the defined extension points as well as how JWT committers can deal with recurring tasks like adding new options to the Eclipse preferences dialog.

Extending JWT-WE through Plugins

Adding Property Sheet Pages

The workflow editor contains support for a multi-tab property sheet (TabbedPropertiesView) which is only activated if additional tabs are provided by plugins. If this is not the case, the classical property sheet is used which does not display any tabs. If the multi-tab sheet is used, a single tab Standard is always shown, which contains the model element properties as would be normally shown in the classical property sheet.

The classical property sheet without tabs that shows the model element properties

The multi-tab sheet with the Standard tab that shows the model element properties

To add a new property sheet page to the editor, it is necessary to define a new property tab in the plugin.xml and fill it with one or more property sections. The implementation of property sections is described in this Eclipse article: [1]. Once the property section have been implemented, they can be registered with the property tab.

The required steps to create one ore more new property tab(s) are:

• Create a new plugin project
• Add jwt-we to your project dependencies
• Add an extension for the point org.eclipse.ui.views.properties.tabbed.propertyTabs
• Create a new propertyTabs child element for this extension point and set its contributorID to org.eclipse.jwt.we.editors.WEEditor
• Create a new propertyTab child element for each property tab that you wish to add to the property sheet. The label corresponds to the displayed name of the tab (use % as prefix to load a language specific caption from plugin.properties). The category should be set to WEStandardCategory. The id should be a unique identifier (use org.eclipse.jwt.we.propertytabs. as prefix) and setting afterTab to org.eclipse.jwt.we.PropertyTabStandard will ensure that the standard tab remains the topmost tab entry.

The required steps to register property sections with the newly defined tab(s) are:

• Add an extension for the point org.eclipse.ui.views.properties.tabbed.propertySections
• Create a new propertySections child element for this extension point and set its contributorID to org.eclipse.jwt.we.editors.WEEditor
• Create a new propertySection child element for each property section that you wish to add to one of your property tabs. The tab must be set to the id of the property tab which should contain this section. The id should be a unique identifier (use org.eclipse.jwt.we.propertysections. as prefix). The class attribute connects this entry to the actual implementation of the section, which should be a subclass of org.eclipse.ui.views.properties.tabbed.AbstractPropertySection. Setting enablesFor to 1 ensures, that the section is only available if a single element is selected. afterSection can be used to specify the arrangement of multiple sections in one tab.
• Create an input child for each section and assign its type a Java class type like org.eclipse.emf.ecore.EObject. The property section/tab is only shown if an element of this type (or a subtype) is selected.

The following excerpt from plugin.xml shows the definition of a new property tab (Advanced) that contains only one section (implemented in org.eclipse.jwt.we.propertiesexample.sections.AdvancedPropertySection). The new property tab is only activated if a model element of the type org.eclipse.jwt.we.model.processes.ActivityNode is selected.

   <extension
         point="org.eclipse.ui.views.properties.tabbed.propertyTabs">
      <propertyTabs
            contributorId="org.eclipse.jwt.we.editors.WEEditor">
         <propertyTab
               afterTab="org.eclipse.jwt.we.propertytabs.Standard"
               category="WEStandardCategory"
               id="org.eclipse.jwt.we.propertytabs.Advanced"
               label="%properties_Advanced_label">
         </propertyTab>
      </propertyTabs>
   </extension>
   <extension
         point="org.eclipse.ui.views.properties.tabbed.propertySections">
      <propertySections
            contributorId="org.eclipse.jwt.we.editors.WEEditor">
         <propertySection
               class="org.eclipse.jwt.we.propertiesexample.sections.AdvancedPropertySection"
               enablesFor="1"
               id="org.eclipse.jwt.we.propertysections.Advanced"
               tab="org.eclipse.jwt.we.propertytabs.Advanced">
            <input
                  type="org.eclipse.jwt.we.model.processes.ActivityNode">
            </input>
         </propertySection>
      </propertySections>
   </extension>

An additional tab named Advanced was added to the multi-tab property sheet