Bug 180864 Change Allow Null option in Cascading Group.[0705]
Description: Change Allow Null option in Cascading Group. Build number:2.2.0.v20070404 Steps to reproduce: 1. New a cascading group and add sub parameter. Expected result: Is Required option in cascading group definition dialog. Actual result: Allow null value option in Cascading Group definition dialog Error log:N/A
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/CascadingParametersDialog.java
{
		String type = getSelectedDataType( );
		String formatStr = ""; 
		if ( DesignChoiceConstants.PARAM_TYPE_STRING.equals( type ) )
		{
			formatStr = new StringFormatter( pattern, ULocale.getDefault( ) ).format( DEFAULT_PREVIEW_STRING );
		}
		else if ( DesignChoiceConstants.PARAM_TYPE_DATETIME.equals( type ) )
		{
			formatStr = new DateFormatter( pattern ).format( new Date( ) );
		}
		else if ( DesignChoiceConstants.PARAM_TYPE_DECIMAL.equals( type )
				|| DesignChoiceConstants.PARAM_TYPE_FLOAT.equals( type ) )
		{
			formatStr = new NumberFormatter( pattern ).format( DEFAULT_PREVIEW_NUMBER );
		}
		else if ( DesignChoiceConstants.PARAM_TYPE_INTEGER.equals( type ) )
		{
			formatStr = new NumberFormatter( pattern ).format( DEFAULT_PREVIEW_INTEGER_NUMBER );
		}
		previewLable.setText( UIUtil.convertToGUIString( formatStr ) );
	}
	private String getColumnName( ScalarParameterHandle handle, String column )
	{
		CachedMetaDataHandle cmdh = null;
		try
		{
			DataSetHandle dataSet = getDataSet( handle );
			if ( dataSet == null )
			{