Name: dfC67450 Date: 10/20/97



The java.text.DecimalFormat.applyPattern(String pattern) allows to apply
illegal patterns such as "#.#.#"
Javadoc says:

 * The following shows the structure of the pattern.
 * pattern := subpattern{;subpattern}
 * subpattern := {prefix}integer{.fraction}{suffix}
 *
 * prefix := '\\u0000'..'\\uFFFD' - specialCharacters
 * suffix := '\\u0000'..'\\uFFFD' - specialCharacters
 * integer := '#'* '0'* '0'
 * fraction := '0'* '#'*
 *
 * Notation:
 * X* 0 or more instances of X
 * (X | Y) either X or Y.
 * X..Y any character from X up to Y, inclusive.
 * S - T characters in S, except those in T
 *
 * The first subpattern is for positive numbers. The second (optional)
 * subpattern is for negative numbers. (In both cases, ',' can occur
 * inside the integer portion--it is just too messy to indicate in BNF.)
 *
 * Here are the special characters used in the parts of the
 * subpattern, with notes on their usage.
 *
 * Symbol Meaning
 * 0 a digit
 * # a digit, zero shows as absent
 * . placeholder for decimal separator
 * , placeholder for grouping separator.
 * ; separates formats.
 * - default negative prefix.
 * % divide by 100 and show as percentage
 * X any other characters can be used in the prefix or suffix
 * ' used to quote special characters in a prefix or suffix.
 *
 * If there is no explicit negative subpattern, - is prefixed to the
 * positive form. That is, "0.00" alone is equivalent to "0.00;-0.00".
 *
 * Illegal formats, such as "#.#.#" or mixing '_' and '*' in the
 * same format, will cause an ParseException to be thrown.
 * From that ParseException, you can find the place in the string
 * where the error occurred.
 *
 
Here is the test demonstrating the bug:

-----------------Test.java------------------------
import java.text.*;

public class Test2 {
    public static void main (String args[]){
        DecimalFormat df = new DecimalFormat();
        try {
            df.applyPattern("#.#.#");
            System.out.println("applyPattern(\"#.#.#\") doesn't throw IllegalArgumentException");
            System.out.println("toPattern() returns \"" + df.toPattern() + "\"");
        } catch (IllegalArgumentException e) {
        }
    }
}
---------Output from the test---------------------
applyPattern("#.#.#") doesn't throw IllegalArgumentException
toPattern() returns "#.##."
--------------------------------------------------

======================================================================

Name: dfC67450 Date: 10/23/97



This method also allows to apply another illegal patterns such as
"#0.0#0#0" and "#,#suffix#0.#"

Yet another test demonstrating the bug
-----------------TestA.java------------------------
import java.text.*;

public class TestA {
    public static void main (String args[]){
        DecimalFormat df = new DecimalFormat();
        try {
            df.applyPattern("#0.0#0#0");
            System.out.println("applyPattern(\"#0.0#0#0\") doesn't throw IllegalArgumentException");
            System.out.println(" toPattern() returns \"" + df.toPattern() + "\"");
            System.out.println();
        } catch (IllegalArgumentException e) {
        }
        try {
            df.applyPattern("#,#suffix#0.#");
            System.out.println("applyPattern(\"#,#suffix#0.#\") doesn't throw IllegalArgumentException");
            System.out.println(" toPattern() returns \"" + df.toPattern() + "\"");
        } catch (IllegalArgumentException e) {
        }
    }
}
---------Output from the test---------------------
applyPattern("#0.0#0#0") doesn't throw IllegalArgumentException
  toPattern() returns "#0.000##"
 
applyPattern("#,#suffix#0.#") doesn't throw IllegalArgumentException
  toPattern() returns "#,#.0##suffix."
--------------------------------------------------

======================================================================