Positive integers only in java.text.NumberFormat?

Question

How would I make a java.text.NumberFormat instance that only allows positive integer numbers?

Actually, it would be nice if it only allowed from 1 and on.

Docs say that the formatting for postive/negative is divided by the ";" character, but putting nothing in the negative formatting or simply not using the ";" doesn't disables negative numbers.

These won't do it apparently:

NumberFormat nf = new DecimalFormat("#;");
// or
NumberFormat nf = new DecimalFormat("#");
// or
NumberFormat nf = new DecimalFormat("#;0");

What exactly do you mean with "only allows positive integer numbers"? Additionally, doc also says: "The negative subpattern is optional; if absent, then the positive subpattern prefixed with the localized minus sign ('-' in most locales) is used as the negative subpattern." — Seelenvirtuose, Oct 27 '14 at 07:27
See if this helps: http://stackoverflow.com/a/16227148/2115983 — Vishnu, Oct 27 '14 at 07:31
What else is there to explain? Positive integer numbers only. I don't know how can I put it in clear terms. Maybe this article can help? http://en.wikipedia.org/wiki/Natural_number Natural numbers, without 0. That means 1, 2, 3, 4, and so on. Not -1, not 2.5. — TheStack, Oct 27 '14 at 21:13
Its a JavaFX text field that applies the formatter. The formatter should only allow for integer numbers >= 1. — TheStack, Oct 27 '14 at 21:26

score 2 · Answer 1 · answered Oct 28 '14 at 06:21

2

Another approach would have been to create your own NumberFormat, that uses a DecimalFormat to convert from string to integer, and then apply any limits to that resulting integer.

answered Oct 28 '14 at 06:21

tbeernot

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Formatting and input validation are two different concerns and should probably be handled by different classes. Good answer from @tbeernot – Guillaume Oct 28 '14 at 06:39

score 0 · Accepted Answer · answered Oct 27 '14 at 21:34

Turns out jfxtras BigDecimalField (link to Javadocs) has a method for setting the minimum value allowed. This, combined with a NumberFormat that only allows for integer numbers, allows me to make a field that only accepts integers bigger or equal than 1.

bigDecimalFld.setFormat( new DecimalFormat( "#;" ) );
bigDecimalFld.setMinValue( new BigDecimal( 1 ) );

Positive integers only in java.text.NumberFormat?

2 Answers2