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/ElementDefn.java
* Whether this element can be extended. If true, elements of this type can
	 * extend from another element of the same type. If false, elements cannot
	 * extend.
	 */
	protected boolean allowExtend = true;
	/**
	 * Determines which class that this element belongs to.
	 */
	protected String javaClass = null;
	/**
	 * The collection of semantic validation trigger definition.
	 */
	private SemanticTriggerDefnSet triggerDefnSet = null;
	/**
	 * The list contains the information that how the property sheet shows an
	 * property for an extension element.
	 */
	protected Map propVisibilites = null;
	/**
	 * The name of the XML element used when serializing this ROM element.
	 */
	protected String xmlElement;
	/**
	 * Sets the Java class which implements this element.
	 * 
	 * @param theClass
	 *            the Java class to set
	 */
	void setJavaClass( String theClass )
	{