Bug 120291 Data source and data set extended from library in a report are invalid.
Description: Data source and data set extended from library in a report are invalid. Steps to reproduce: 1. Drag a data source and data set from library explorer view. Noticed that their names are different from the names in library. 2. I want to use the data source extended from library to create a new data set. The data source is invalid. 3. The data set from library is also invalid. When editing it, NullPointerException is thrown out.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/StructureFactory.java
{
		return new SortKey( );
	}
	/**
	 * Creates an empty column hint structure.
	 * 
	 * @return an empty column hint structure
	 */
	public static ColumnHint createColumnHint( )
	{
		return new ColumnHint( );
	}
	/**
	 * Creates an empty highlight rule structure.
	 * 
	 * @return an empty highlight rule structure
	 */
	public static HighlightRule createHighlightRule( )
	{
		return new HighlightRule( );
	}
	/**
	 * Creates an empty map rule structure.
	 * 
	 * @return an empty map rule structure
	 */
	public static MapRule createMapRule( )
	{
		return new MapRule( );
	}