Bug 181121 Model should provide utility method for cube to get correspond dimension key.
In model cube handle, the relation of cube data set and dimension data sets are managed by a series of dimension condition handles.We need model to add utility method so that we can easily get corresponding dimension data set column names according to given cube dimension keys.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/parser/StructureState.java
* @param propDefn
	 *            the definition of the property which holds this structure
	 * @param theList
	 *            the structure list
	 */
	StructureState( ModuleParserHandler theHandler, DesignElement element,
			PropertyDefn propDefn, ArrayList theList )
	{
		super( theHandler, element );
		assert propDefn != null;
		assert theList != null;
		this.propDefn = propDefn;
		this.list = theList;
	}
	/**
	 * Constructs the state of the structure which is in one structure list.
	 * 
	 * @param theHandler
	 *            the design parser handler
	 * @param element
	 *            the element holding this structure
	 * @param propDefn
	 *            the definition of the property which holds this structure
	 * @param parentStruct
	 *            the structure that contains the current structure
	 */
	StructureState( ModuleParserHandler theHandler, DesignElement element,
			PropertyDefn propDefn, IStructure parentStruct )
	{
		super( theHandler, element );