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/core/DesignElement.java
* @param module
	 *            the root module
	 * @return true if this element is based on a template parameter definition,
	 *         otherwise false
	 */
	public boolean isTemplateParameterValue( Module module )
	{
		return getTemplateParameterElement( module ) != null;
	}
	/**
	 * Resolves a list of element reference.
	 * 
	 * @param module
	 *            the module information needed for the check, and records any
	 *            errors
	 * @param prop
	 *            the property whose type is element reference
	 * @return the list of element reference value and each reference value is
	 *         tried to resolve
	 */
	public List resolveElementReferenceList( Module module,
			ElementPropertyDefn prop )
	{
		Object value = propValues.get( prop.getName( ) );
		assert value == null || value instanceof List;
		assert prop.getTypeCode( ) == PropertyType.LIST_TYPE
				&& prop.getSubTypeCode( ) == PropertyType.ELEMENT_REF_TYPE;
		if ( value == null )
			return null;
		List valueList = (List) value;