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
return state;
			}
		}
		return super.generalJumpTo( );
	}
	/**
	 * Creates structure instance given the structure name.
	 * 
	 * @param structDefn
	 *            the definition of the structure to create
	 * @return the structure instance created.
	 */
	static IStructure createStructure( StructureDefn structDefn )
	{
		synchronized ( StructureState.class )
		{
			if ( structDict == null )
				populateStructDict( );
		}
		assert structDefn != null;
		assert structDict != null;
		IStructure struct = null;
		try
		{
			Class c = (Class) structDict.get( structDefn.getName( )
					.toLowerCase( ) );
			if ( c == null )
				return null;
			struct = (IStructure) c.newInstance( );
		}