Bug 149251 Inconsistent Handling of a Non-inheritable ROM Property
For a ROM property defined to be non-inheritable, an empty string property value should be consistently handled as an empty string, not as null. For example, an oda.dataSource extension defines a data source property with canInherit=false. When a oda-data-source handle get saved in a report design, it correctly includes the tag for such property, even when an empty string value is specified. <oda-data-source extensionID="my.oda.plugin" name="my Data Source" id="24"> ... <property name="ApplicationServer"></property> </oda-data-source> However, later when using the DE API to read its property value, a null is returned. Then when the report design is subsequently saved, the property tag is lost. Expects that an empty string value of a non-inhertiable property should be preserved.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/ModuleHandle.java
* Returns a cascading parameter group handle with the given group name
	 * 
	 * @param groupName
	 *            name of the cascading parameter group.
	 * @return a handle to the cascading parameter group. Returns
	 *         <code>null</code> if the cascading group with the given name is
	 *         not found.
	 */
	public CascadingParameterGroupHandle findCascadingParameterGroup(
			String groupName )
	{
		DesignElement element = module.findParameter( groupName );
		if ( element == null || !( element instanceof CascadingParameterGroup ) )
			return null;
		return (CascadingParameterGroupHandle) element.getHandle( element
				.getRoot( ) );
	}
	/**
	 * Returns a slot handle to work with the styles within the report. Note
	 * that the order of the styles within the slot is unimportant.
	 * 
	 * @return A handle for working with the styles.
	 */
	public SlotHandle getStyles( )
	{
		return getSlot( IReportDesignModel.STYLE_SLOT );
	}
	/**
	 * Gets a handle to deal with a translation. A translation is identified by
	 * its resourceKey and locale.