Bug 319351 Refactor data set editor pages' codes[28193]
Build Identifier: 20100708 Refactor data set editor pages' codes. Reproducible: Always
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/data/ui/util/DataSetProvider.java
private transient Hashtable htColumns = new Hashtable( 10 );
	private static Hashtable htDataSourceExtensions = new Hashtable( 10 );
	private transient Hashtable sessionTable = new Hashtable( 10 );
	
	private static final char RENAME_SEPARATOR = '_';
	private static String UNNAME_PREFIX = "UNNAMED"; 
	private boolean needToFocusOnOutput = true;
	/**
	 * @return
	 */
	private static DataSetProvider newInstance( )
	{
		return new DataSetProvider( );
	}
	/**
	 * 
	 * @return
	 */
	public static DataSetProvider getCurrentInstance( )
	{
		if ( instance == null )
			instance = newInstance( );
		return instance;
	}
	/**
	 * get columns data by data set name
	 * 
	 * @param dataSetName
	 * @param refresh