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
* null if either the property is unset, or the reference is unresolved.
	 * 
	 * @param module
	 *            the module
	 * @param propName
	 *            the name of the element reference property to get
	 * @return the element referenced by the property
	 */
	public DesignElement getReferenceProperty( Module module, String propName )
	{
		ElementRefValue ref = (ElementRefValue) getProperty( module, propName );
		if ( ref == null )
			return null;
		return ref.getElement( );
	}
	/**
	 * Returns whether this element has references. That is, whether any other
	 * elements reference this one using an element reference property. This
	 * query does not check for "extends" references.
	 * 
	 * @return whether other elements refer to this one
	 */
	public boolean hasReferences( )
	{
		return false;
	}
	/**
	 * Creates the Factory data structures for specialized property access. This
	 * method uses specialized property resolution rules:
	 * <p>