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/metadata/ElementRefPropertyType.java
if ( !target.getDefn( ).isKindOf( targetDefn ) )
			throw new PropertyValueException( target.getName( ),
					PropertyValueException.DESIGN_EXCEPTION_WRONG_ELEMENT_TYPE,
					PropertyType.ELEMENT_REF_TYPE );
		
		return refValue;
	}
	/**
	 * Converts this property type into a string, return the element name of the
	 * referenced element.
	 * 
	 * @return the element name of the referenced element, return
	 *         <code>null</code> if value is null;
	 */
	public String toString( Module module, PropertyDefn defn, Object value )
	{
		if ( value == null )
			return null;
		if ( value instanceof String )
			return (String) value;
		ElementRefValue refValue = (ElementRefValue) value;
		if ( !StyledElement.STYLE_PROP.equals( defn.getName( ) ) )
		{
			return ReferenceValueUtil.needTheNamespacePrefix(
					(ReferenceValue) value, module );
		}
		return refValue.getName( );
	}
	/**