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/PropertySearchStrategy.java
* 
	 * @return the instance of <code>PropertySearchStrategy</code>
	 */
	public static PropertySearchStrategy getInstance( )
	{
		return instance;
	}
	/**
	 * Gets a property value given its definition. This version does the
	 * property search with style reference, extends reference and containment.
	 * The default value style property defined in session is also searched, but
	 * the default value defined in ROM will not be returned.
	 * 
	 * @param module
	 *            the module
	 * @param element
	 *            the element to start search
	 * @param prop
	 *            definition of the property to get
	 * @return The property value, or null if no value is set.
	 */
	public Object getPropertyExceptRomDefault( Module module,
			DesignElement element, ElementPropertyDefn prop )
	{
		if ( prop.isIntrinsic( ) )
		{
			
			Object value = element.getIntrinsicProperty( prop.getName( ) );
			if ( value != null )
				return value;