Bug 146709 Dates still do not work from main report to sub reports...
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/util/ParameterValidationUtil.java
if ( number == null )
				return null;
			return new Double( number.doubleValue( ) );
		}
		else if ( DesignChoiceConstants.PARAM_TYPE_DECIMAL
				.equalsIgnoreCase( dataType ) )
		{
			Number number = doValidateNumber( dataType, value, locale );
			if ( number == null )
				return null;
			return new BigDecimal( number.doubleValue( ) );
		}
		else if ( DesignChoiceConstants.PARAM_TYPE_BOOLEAN
				.equalsIgnoreCase( dataType ) )
		{
			return doValidateBoolean( value, locale );
		}
		else if ( DesignChoiceConstants.PARAM_TYPE_STRING
				.equalsIgnoreCase( dataType ) )
		{
			return value;
		}
		else
		{
			assert false;
			return null;
		}
	}
	/**
	 * Validates the input value at the given locale. The format is: short date