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
*/
	void setCanExtend( boolean flag )
	{
		allowExtend = flag;
	}
	/**
	 * Returns whether elements of this class can be extended.
	 * 
	 * @return True if the element can be extended, false if not.
	 */
	public boolean canExtend( )
	{
		return allowExtend;
	}
	/**
	 * Marks this element as abstract. Users never see abstract elements: they
	 * exist to simplify the description of other elements.
	 * 
	 * @param flag
	 *            true if the element is to be abstract, false if it is to be
	 *            concrete (user-visible)
	 */
	void setAbstract( boolean flag )
	{
		abstractElement = flag;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.model.metadata.IObjectDefn#findProperty(java.lang.String)