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
*             one defined in the <code>defn</code>.
	 */
	public Object validateValue( Module module, PropertyDefn defn, Object value )
			throws PropertyValueException
	{
		if ( value == null )
			return null;
		ElementDefn targetDefn = (ElementDefn) defn.getTargetElementType( );
		if ( value instanceof String )
		{
			logger.log( Level.FINE,
					"Validate the value of the element reference property as a string: " 
							+ value );
			return validateStringValue( module, targetDefn, defn,
					(String) value );
		}
		if ( value instanceof DesignElement )
		{
			logger.log( Level.FINE,
					"Validate the value of the element reference property as a DesignElement " 
							+ ( (DesignElement) value ).getName( ) );
			DesignElement target = (DesignElement) value;
			return validateElementValue( module, targetDefn, defn, target );
		}
		
		logger.log( Level.SEVERE, "Invalid value type: " + value ); 
		throw new PropertyValueException( value,
				PropertyValueException.DESIGN_EXCEPTION_INVALID_VALUE,
				PropertyType.ELEMENT_REF_TYPE );
	}