Java Code Examples for java.text.Format

Following code examples demonstrate how to use java.text.Formatfrom android. These examples are extracted from various highly rated open source projects. You can directly use these code snippets or view their entire linked source code. These snippets are extracted to provide contextual information about how to use this class in the real world. These samples also let you understand some good practices on how to use java.text.Formatand various code implementation of this class.

    public void test_clone() {
        try {
            Format fm = new MockFormat();
            Format fmc = (Format) fm.clone();
            assertEquals(fm.getClass(), fmc.getClass());
        } catch (Exception e) {
            fail("Unexpected exception " + e.toString());

    private class MockFormat extends Format {

        public StringBuffer format(Object obj, StringBuffer toAppendTo,
                FieldPosition pos) {
            if (obj == null)
                throw new NullPointerException("obj is null");
            return new StringBuffer("");

        public Object parseObject(String source, ParsePosition pos) {
            return null;

    public default void verifyGenericType()
    throws Exception {
        final Class<SUT> sut = createNewSUT();
        assertTrue("This j8unit test interface is used with a generic type that is illegaly not assignable to Format.class!",

Format is an abstract base class for formatting locale-sensitive information such as dates, messages

, and numbers.

Format defines the programming interface for formatting locale-sensitive objects into Strings (the format method) and for parsing Strings back into objects (the parseObject method).

Generally, a format's parseObject method must be able to parse any string formatted by its format method. However, there may be exceptional cases where this is not possible. For example, a format method might create two adjacent integer numbers with no separator in between, and in this case the parseObject could not tell which digits belong to which number. Subclassing

The Java Platform provides three specialized subclasses of Format-- DateFormat, MessageFormat, and NumberFormat--for formatting dates, messages, and numbers, respectively.

Concrete subclasses must implement three methods: format(Object obj, StringBuffer toAppendTo, FieldPosition pos) formatToCharacterIterator(Object obj) parseObject(String source, ParsePosition pos) These general methods allow polymorphic parsing and formatting of objects and are used, for example, by MessageFormat. Subclasses often also provide additional format methods for specific input types as well as parse methods for specific result types. Any parse method that does not take a ParsePosition argument should throw ParseException when no text in the required format is at the beginning of the input text.

Most subclasses will also implement the following factory methods: getInstance for getting a useful format object appropriate for the current locale getInstance(Locale) for getting a useful format object appropriate for the specified locale In addition, some subclasses may also implement other getXxxxInstance methods for more specialized control. For example, the NumberFormat class provides getPercentInstance and getCurrencyInstance methods for getting specialized number formatters.

Subclasses of Format that allow programmers to create objects for locales (with getInstance(Locale) for example) must also implement the following class method: public static Locale[] getAvailableLocales()

And finally subclasses may define a set of constants to identify the various fields in the formatted output. These constants are used to create a FieldPosition object which identifies what information is contained in the field and its position in the formatted result. These constants should be named item_FIELD where item identifies the field. For examples of these constants, see ERA_FIELD and its friends in DateFormat. Synchronization

Formats are generally not synchronized. It is recommended to create separate format instances for each thread. If multiple threads access a format concurrently, it must be synchronized externally. @see java.text.ParsePosition @see java.text.FieldPosition @see java.text.NumberFormat @see java.text.DateFormat @see java.text.MessageFormat @author Mark Davis

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