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
* <code>DesignElement</code> class, or one of its subclasses. For
 * convenience, we often use the word "property" to mean a property value.
 * Property values can be in two states: set or unset. An unset value generally
 * causes the model to inherit the property value from the parent element (if
 * any). Properties in BIRT work much like properties in JavaScript objects.
 * </dd>
 * </dl>
 * 
 * <h3>System and User Properties</h3>
 * 
 * BIRT defines a wide range of element types, each with a wide range of
 * properties. Properties defined by BIRT itself are called
 * <em>system properties</em>. They are defined as part of the element type
 * definition in the meta-data file. System properties are of two types: normal
 * or <em>intrinsic</em>. An intrinsic property is one defined by a member
 * variable the DesignElement class or one of its subclasses. An normal property
 * is stored as a name/value pair in the DesignElement class.
 * <p>
 * BIRT also allows users to define their own properties. Such properties are
 * called, unsurprisingly, user properties. User properties are defined on an
 * element and are available to that element, and any elements that derive from
 * that element (see below.)
 * <p>
 * For the most part, system and user properties are defined in the same way as
 * implemented by the {@link ElementPropertyDefn}class. The few differences are
 * represented by the {@link SystemPropertyDefn}and
 * {@link org.eclipse.birt.report.model.api.core.UserPropertyDefn}classes.
 * 
 * <h3>Element Inheritance</h3>
 *