Bug 166015 Refactor designer actions to eclipse command framework
Eclipse command framework provide a more explicit way to manage UI actions contributions, we can take it's advantage to make our actions code more clean and maintainable.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/internal/ui/editors/schematic/actions/InsertColumnAction.java
for(Iterator it = columns.iterator();it.hasNext();)
		{
			if ( !canDrop( (ColumnHandle) it.next( ) ) )
			{
				return false;
			}
		}
		return true;
	}
	
	private boolean canDrop(ColumnHandle handle)
	{
		return ((ColumnHandle)handle).canDrop();
	}
	/**
	 * Runs action.
	 *  
	 */
	public void run( )
	{
		if ( Policy.TRACING_ACTIONS )
		{
			System.out.println( "Insert column action >> Run ..." ); 
		}
		if ( getTableEditPart( ) != null && getColumnHandles( ).size( ) == 1 )
		{
			getTableEditPart( ).insertColumn( getColumnNumber( getColumnHandles( ).get( 0 ) ) );
		}
	}
}