[Fmt-Nu] Method java.text.DecimalFormat.applyPattern(String pattern) works incorrectly.

Name: dsR10051 Date: 09/14/2001



The method of class java.text.DecimalFormat
public void applyPattern(String pattern)
works incorrectly if the suffix of the pattern
contains the special characters.
In this case method can throw IllegalArgumentException
or can ignore the special characters and continue normal job processing.

The javadoc for pattern syntax of java.text.DecimalFormat says:
(captured from jdk1.3 on account of simplicity of declaration.

pattern := pos_pattern{';' neg_pattern}
pos_pattern := {prefix}number{suffix}
suffix := '\u0000'..'\uFFFD' - special_characters

and for Special Pattern Characters:
"They must be quoted, unless noted otherwise, if
they are to appear in the prefix or suffix as literals."

So, suffix that contains any special characters should be considered as invalid
and IllegalArgumentException should be thrown, unless noted otherwise.

If suffix contains the special character that is first entry in the pattern,
the IllegalArgumentException is thrown by the applyPattern method.
But if number (shown above in the second line of the pattern syntax) contains
this special character, applyPattern ignores it and set suffix
of the DecimalFormat object to the suffix pattern without this character.
For example, if "#.#suffix0" pattern value is passed to the applyPattern method,
the IllegalArgumentException is thrown by it. But if the pattern is
"0.0suffix0", DecimalFormat suffix is setted to "suffix" and no
exception is thrown.

Here is minimized test:

import java.text.*;

public class DecimalFormatTest01 {

    public static void main (String[] args) {
        String pattern1 = "#.#suffix0";
        String pattern2 = "0.0suffix0";
        DecimalFormat df = new DecimalFormat();
        try {
            df.applyPattern(pattern1);
            System.out.println("FAILED: IllegalArgumentException expected for pattern " + pattern1);
            System.out.println("Suffix: " + df.getPositiveSuffix());
        } catch (IllegalArgumentException iae) {
            // OKAY
        }
        try {
            df.applyPattern(pattern2);
            System.out.println("FAILED: IllegalArgumentException expected for pattern " + pattern2);
            System.out.println("Suffix: " + df.getPositiveSuffix());
        } catch (IllegalArgumentException iae) {
            // OKAY
        }
    }
}
--- Output ---
$ /set/jdk-builds/JDK1.4.0beta2-b78/solaris/bin/java DecimalFormatTest01
FAILED: IllegalArgumentException expected for pattern 0.0suffix0
Suffix: suffix
$
________________

Here is the letter from IBM that sent to jck-comments.

12) api/java_text/DecimalFormat/index.html#Pattern: DecimalFormat
applyPattern and toPattern tests subtests: 0044, 0055, 0058

Test Description:

These tests perform domain testing of input and output conditions, and
external pre-conditions for class DecimalFormat, method public void
applyPattern(String pattern).

Specification:

The Java? 2 Platform, Standard Edition, v1.3 API Specification
(java.lang.DecimalFormat): "Illegal patterns, such as "#.#.#" or "#.###,
###", will cause DecimalFormat to throw an IllegalArgumentException with a
message that describes the problem."
The Java? 2 Platform, Standard Edition, v1.3 API Specification
(java.lang.DecimalFormat pattern syntax):
"number := integer{'.' fraction}{exponent}
prefix := '\u0000'..'\uFFFD' - special_characters
suffix := '\u0000'..'\uFFFD' - special_characters
integer := min_int | '#' | '#' integer | '#' ',' integer
min_int := '0' | '0' min_int | '0' ',' min_int
fraction := '0'* '#'* exponent := 'E' '0' '0'*"

Rationale to Exclude:

Two of the applyPattern tests call the method applyPattern with string
argument "###,000.000suffix2##". By definintion in the API specification,
only characters from '\u0000' through '\uFFFD', excluding the special
characters, are valid for the suffix. The specificaiton defines '#' as a
special character, hence pattern "###,000.000suffix2##" is invalid and
should throw an IllegalArgumentException. For this reason, this test should
be excluded because it is testing Sun's implementation of the applyPattern
() method, which allows for such an invalid pattern, and not the
specification.
--- end of letter ---

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