Bug 207120 Please model provide an API for data type conversion.
Currently, there're two data types: column data type and parameter data type. But they're inconsistent. Could model provide APIs for conversion between the two types. Thanks. In addition: please check the code into head and 2.2.1 branch, because we have a 2.2.1 bug to fix.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/ModuleUtil.java
e.setProperty( ImageHandle.ACTION_PROP, action );
			action.setContext( new StructureContext( e, ImageHandle.ACTION_PROP) );
			return getActionHandle( e.getHandle( module ) );
		}
		if ( !streamData.markSupported( ) )
			streamData = new BufferedInputStream( streamData );
		assert streamData.markSupported( );
		parse( handler, streamData, "" ); 
		if ( element != null )
		{
			Action action = (Action) image.getProperty( handler.getModule( ),
					IImageItemModel.ACTION_PROP );
			e.setProperty( IImageItemModel.ACTION_PROP, action );
			action.setContext( new StructureContext( e, ImageHandle.ACTION_PROP) );
		}
		return getActionHandle( e.getHandle( module ) );
	}
	/**
	 * Gets the action handle of this element.
	 * 
	 * @param element
	 * @return action handle
	 */
	private static ActionHandle getActionHandle( DesignElementHandle element )
	{
		PropertyHandle propHandle = element
				.getPropertyHandle( IImageItemModel.ACTION_PROP );
		Action action = (Action) propHandle.getValue( );
		if ( action == null )
			return null;