Bug 139343 [regression]Can not use __document to preview report document when deploy birt.
Summary: [regression]Can not use __document to preview report document when deploy birt. Steps to reproduce: 1. Deploy birt 2. Render a report document 3. Preview the report document by using __document Result: The design file C:\apps\jakarta-tomcat-5.5.7\webapps\birt060428\ has error and can not be run.
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/context/BaseAttributeBean.java
Object parameterValue = parameters.get( parameterName );
			if ( parameterObj.isHidden( ) )
			{
				continue;
			}
			if ( parameterValue == null && !parameterObj.allowNull( ) )
			{
				missingParameter = true;
				break;
			}
			if ( IScalarParameterDefn.TYPE_STRING == parameterObj.getDataType( ) )
			{
				String parameterStringValue = (String) parameterValue;
				if ( parameterStringValue != null
						&& parameterStringValue.length( ) <= 0
						&& !parameterObj.allowBlank( ) )
				{
					missingParameter = true;
					break;
				}
			}
		}
		return missingParameter;
	}
	private Map getParsedParameters( IViewerReportDesignHandle design,
			Collection parameterList, HttpServletRequest request,
			InputOptions options ) throws ReportServiceException
	{
		Map params = new HashMap( );
		for ( Iterator iter = parameterList.iterator( ); iter.hasNext( ); )