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
*/
	public void dropUserPropertyDefn( UserPropertyDefn prop )
	{
		assert getDefn( ).allowsUserProperties( );
		assert userProperties != null;
		assert userProperties.get( prop.getName( ) ) == prop;
		userProperties.remove( prop.getName( ) );
	}
	/**
	 * Gets a user property definition defined on this class itself.
	 * <p>
	 * Part of: User-defined property system.
	 * 
	 * @param propName
	 *            The internal name of the user-defined property.
	 * @return The user-defined property definition, if any.
	 */
	public UserPropertyDefn getLocalUserPropertyDefn( String propName )
	{
		if ( userProperties == null )
			return null;
		return (UserPropertyDefn) userProperties.get( propName );
	}
	/**
	 * Gets the definition of a user-defined property defined in this element or
	 * somewhere up the inheritance chain.
	 * <p>
	 * Part of: User-defined property system.
	 * 
	 * @param propName