Add BinaryHandler for DecimalFormat

[zdenek-jonas]

Add BinaryHandler for DecimalFormat class in java.text package.

Generic Handler does not load the whole class correctly.

stored:

loaded:

DigitList ist null.
In some basis scenario is an Exception raised:

java.lang.NullPointerException: Cannot enter synchronized block because "this.digitList" is null

	at java.base/java.text.DecimalFormat.doubleSubformat(DecimalFormat.java:750)
	at java.base/java.text.DecimalFormat.format(DecimalFormat.java:682)
	at java.base/java.text.DecimalFormat.format(DecimalFormat.java:635)
	at java.base/java.text.NumberFormat.format(NumberFormat.java:368)
	at test.microstream.various.text.DecimalFormatTest.decimalFormatAsFieldInDataClass(DecimalFormatTest.java:33)
	at java.base/java.lang.reflect.Method.invoke(Method.java:565)

    @Test
    void decimalFormatAsFieldInDataClass()
    {
        DecimalFormat df = new DecimalFormat("0.###");
        double sample = 3.14159;

        DecimalData root = new DecimalData(df);
        try (EmbeddedStorageManager storageManager = EmbeddedStorage.start(root, tempDir)) {
            storageManager.storeRoot();
        }

        DecimalData loaded = new DecimalData();
        try (EmbeddedStorageManager storageManager = EmbeddedStorage.start(loaded, tempDir)) {
            assertEquals(df.format(sample), loaded.getFormat().format(sample));
        }
    }

    private static class DecimalData
    {
        private DecimalFormat format;

        public DecimalData(DecimalFormat format)
        {
            this.format = format;
        }

        public DecimalData()
        {
        }

        public DecimalFormat getFormat()
        {
            return format;
        }

        public void setFormat(DecimalFormat format)
        {
            this.format = format;
        }
    }
}

[hg-ms]

The digitList field of DecimalFormat is null because it’s marked transient.
It could be initialized as a new java.text.DigitList after deserialization.
There are also other transient fields that should be initialized, see readObject method.
Doing so requires a custom type handler to be implemented.