Develop Reference

Convert to unixtime: same input, different output

Maybe this is a recurrent issue, but I need to explain my problem.
I must convert date+hour to Unix time format. I use Apache Commons Lang library, DateUtils class:
Date date = DateUtils.parseDate(strStartDateTime, new String[] { "ddMMyyyyHHmmss" });
Long dateLong = new Long(date.getTime());
Maybe Java Date class is old for this, but it seems to work fine.
But lately, I have detected that the same input, in right expected format, is returning different output in different executions.
I have been looking for a similar issue, and I have read that Java Date is old, joda-time library is recommended, etc.
It would be easy to convert with joda-time, but, why is this happening? Is reliable the code above? It's very likely I'm not taking something into account.
Any help or suggestion would be very appreciated.
Thanks in advance.

Excuse me, but finally I found the error. There was a wrong attribute definition.
It was my programming error; nothing related to time conversion. Thanks

How do I add the new currency code to Java?

The Chinese currency has the ISO 4217 code CNY. Since free global trading in that currency is restricted though, there's a second 'offshore' currency equivalent, called CNH. Wikipedia has a bit of summary of this all.
CNH isn't in ISO 4217, but I'd like to be able to use it in my app without having to write my own Currency class. Presumably there's some kind of list somewhere inside the JVM install. How do I go about adding additional currency codes?
EDIT: See this question for dealing with this in Java 7

Looks like support for this was added with Java 7.
For earlier versions, you could use an equivalent Currency class of your own devising, or less happily, replace the default java.util.Currency class (or java.util.CurrencyData, which contains the raw data) in your classpath (whitepaper).

Java Unit conversion

I have a database table which stores the units name in full like liters, kilograms, milliliters, milligrams etc.. I need a library to recogonize these units and convert it to the unit I wish to. How do i do this ?
Code Logic:
I will read the unit "liters" from database and i wish to convert it to milli-liters so her the input is "20 liters" and output should be "20000 milli-liters"
I downloaded JScience library but i am not sure how to do this. please tel me how to use that or suggest any alternative. It would be better if you explain me with a code sample. Thanks!!

I'm inclined to say use Frink, but it does WAY more than you need here, although it does solve the problem
20 litres -> milliliters
//gives 20000
And it is just a cool little language. In java you'd have to run it like any other scripting library. The website has loads of info

I'm not aware that JScience provides a facility for parsing strings like "20 liters" (that spelling makes me cringe...), so you'll probably have to handle that yourself, by tokenizing the string into quantities and units.
Once you have that, you can use JScience to convert between units easily enough, although obviously converting from litres to milliltres is trivial. But in principle, it's something like:
Measure<Integer, Volume> input = Measure.valueOf(20, NonSI.LITRE);
Measure<Integer, Volume> output = input.to(SI.MILLI(NonSI.LITRE));
System.out.println(output);

Porting XML parsing from Java to Objective C

I am trying to port code written in Java to Objective C (for iPhone), but I'm kind of confused about a few lines of my code (mentioned below). How should I port this efficiently?
Namespace nmgrhistory=Namespace.getNamespace("history", "http://www.mywebsite.com/History.xsd");
pEventEl.addContent(new Element("History",nmgrhistory));
Namespace nmgrState=Namespace.getNamespace("state", "http://www.mywebsite.com/State.xsd");
pEventEl.addContent(new Element("State",nmgrState));
Iterator<Element> eld=(Iterator<Element>) pEventEl.getChild(
pEventEl.getName() == "event"? "./history:history/state:state" : "./state:state",pEventEl.getNamespace());
I'm not very sure about the replacements for the classes Namespace, Iterator and Element.
Anybody having idea or having done this before, please enlighten me.

Ok... So although these are not the actual replacements ... But basically what u need for parsing XML in Objecive - C is "NSXMLParser"
so u can say that NSXMLParser is the replacement for Namespace
And for "Iterator" NSXMLParserDelegate has a method named:-
– parser:didStartElement:namespaceURI:qualifiedName:attributes:
OR
– parser:foundCharacters:

I don't know java, but the url's your are pointing at are .xsd files which are xml definition files. XML parsing on iOS is somewhat limited out of the box: NSXMLParser.
I strongly recommend one of the bazillion open source XML parsers. They're much more user friendly.

Well thanks to all for making the efforts to answer, but I got a nice library TouchXML that solves the purpose.

Rounding Half Up with Decimal Format in Android

I want to set the Rounding Mode to HALF_UP on my DecimalFormat, but eclipse is telling me that setRoundingMode() is not available on the DecimalFormat class. My project properties (and the overall Eclipse properties) are using the 1.6 compiler. The developer.android.com site says that I can use either Java 5 or 6 so I'm not sure what the problem is.
import java.math.RoundingMode;
import java.text.DecimalFormat;
completedValueFormatter = NumberFormat.getNumberInstance();
DecimalFormat completedDecimalFormat = (DecimalFormat)completedValueFormatter;
completedDecimalFormat.setRoundingMode(RoundingMode.HALF_UP);
I've also tried using the android tools to generate an ant-based project, tried this code in the project and also got the same compile error. So it doesn't appear to be related to Eclipse. It seems related to the Android API.
Any suggestions?

This doesn't truly answer why I can't use the Java 6 .setRoundingMode(RoundingMode) method in DecimalFormat, but it is at least a work-around.
int numDigitsToShow = this.completedValueFormatter.getMaximumFractionDigits();
BigDecimal bigDecimal = new BigDecimal(valueToBeRounded);
BigDecimal roundedBigDecimal = bigDecimal.setScale(numDigitsToShow, RoundingMode.HALF_UP);
return this.completedValueFormatter.format(roundedBigDecimal.doubleValue());
I create a BigDecimal with the value I need to round, then I get a BigDecimal of that value with the scale set to the number of digits I need to round my values to. Then I pass that rounded value off to my original NumberFormat for conversion to String.
If anyone has a better solution, I'm all ears!

Here is what I suspect the problem is, (assuming I am reading the docs properly) and its a doozy:
According to the java.text.DecimalFormat API documentation, you are not actually getting the Runtime Implimentation of the Java 1.6 RE, but are getting an android "Enhanced Version" that clearly doesn't include the setRoundingMode, which frankly bites.
"This is an enhanced version of DecimalFormat that is based on the standard version in the RI. New or changed functionality is labeled NEW."
A weakness in Java for many many many years has been the DecimalFormat class defaulted to HALF_ROUND_UP and had no way to change that, until JVM 1.6. Pity to see Android is keeping this need to kludge alive.
So looks like we are stuck Kludging BigDecimal scale Settings to format output all over any app that needs it, instead of simply being able to rely on a formatter call alone to get the job done. Not the end of the world, but very disappointing Google.
Of course that same doc says that setRondingMode() works, so perhaps this is a all out BUG??

I guess this would be the best option
http://download.oracle.com/javase/1.4.2/docs/api/java/lang/Math.html#ceil(double)