Bug 152830 Need model's support to add jar files
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/writer/ModuleWriter.java
}
	/**
	 * Write an XML attribute from an element property.
	 * 
	 * @param obj
	 *            the element that has the property
	 * @param attr
	 *            the XML attribute name
	 * @param propName
	 *            the name of the property to write
	 */
	protected void attribute( DesignElement obj, String attr, String propName )
	{
		ElementPropertyDefn prop = obj.getPropertyDefn( propName );
		assert prop != null;
		Object value = obj.getLocalProperty( getModule( ), prop );
		if ( value == null )
			return;
		String xml = prop.getXmlValue( getModule( ), value );
		if ( xml == null )
			return;
		writer.attribute( attr, xml );
	}
	/**
	 * Returns the tag according to the simple property type. If the property
	 * type is structure or structure list, this method can not be used.
	 * 
	 * <ul>
	 * <li>EXPRESSION_TAG, if the property is expression;
	 * <li>XML_PROPERTY_TAG, if the property is xml;