ICU-3668 document that user subclasses are not supported in the Format hierarchy

X-SVN-Rev: 14833

icu4c/source/i18n/unicode/choicfmt.h

@@ -246,6 +246,10 @@ class MessageFormat;
  *       return 0;
  *   }
  * \endcode
+ *
+ * <p><em>User subclasses are not supported.</em> While clients may write
+ * subclasses, such code will not necessarily work and will not be
+ * guaranteed to work stably from release to release.
  */
 class U_I18N_API ChoiceFormat: public NumberFormat {
 public:

icu4c/source/i18n/unicode/datefmt.h

@@ -124,6 +124,10 @@ class TimeZone;
  *   <li>   Align any particular field, or find out where it is for selection
  *          on the screen.
  * </ul>
+ *
+ * <p><em>User subclasses are not supported.</em> While clients may write
+ * subclasses, such code will not necessarily work and will not be
+ * guaranteed to work stably from release to release.
  */
 class U_I18N_API DateFormat : public Format {
 public:

icu4c/source/i18n/unicode/decimfmt.h

@@ -550,6 +550,12 @@ class ChoiceFormat;
  *
  * <p>DecimalFormat objects are not synchronized.  Multiple
  * threads should not access one formatter concurrently.
+ *
+ * <p><strong>Subclassing</strong>
+ *
+ * <p><em>User subclasses are not supported.</em> While clients may write
+ * subclasses, such code will not necessarily work and will not be
+ * guaranteed to work stably from release to release.
  */
 class U_I18N_API DecimalFormat: public NumberFormat {
 public:

icu4c/source/i18n/unicode/format.h

@@ -83,13 +83,9 @@ class ResourceBundle;
  * retured for methods which take no ParsePosition.  For the method
  * that takes a ParsePosition, the index parameter is left unchanged.
  * <P>
- * [Subclassing.] All base classes that provide static functions that
- * create objects for Locales must implement the following static:
- * <pre>
- * \code
- *       public static const Locale* getAvailableLocales(long&)
- * \endcode
- * </pre>
+ * <em>User subclasses are not supported.</em> While clients may write
+ * subclasses, such code will not necessarily work and will not be
+ * guaranteed to work stably from release to release.
  */
 class U_I18N_API Format : public UObject {
 public:

icu4c/source/i18n/unicode/msgfmt.h

@@ -227,7 +227,7 @@ class DateFormat;
  * the string patterns), then be careful not to produce a format that
  * recurses on itself, which will cause an infinite loop.
  * <P>
- * <EM>Note:<EM>Subformats are numbered by their order in the pattern.
+ * <EM>Note:</EM> Subformats are numbered by their order in the pattern.
  * This is <EM>not</EM> the same as the argumentIndex.
  * <pre>
  * \code
@@ -238,6 +238,10 @@ class DateFormat;
  *    format2 affects the second variable {0}
  * \endcode
  * </pre>
+ *
+ * <p><em>User subclasses are not supported.</em> While clients may write
+ * subclasses, such code will not necessarily work and will not be
+ * guaranteed to work stably from release to release.
  */
 class U_I18N_API MessageFormat : public Format {
 public:

icu4c/source/i18n/unicode/numfmt.h

@@ -128,6 +128,11 @@ typedef const void* URegistryKey;
  * widthToAlignmentPoint) before drawing the text.  It also works
  * where there is no decimal, but possibly additional characters at
  * the end, e.g. with parentheses in negative numbers: "(12)" for -12.
+ * <p>
+ * <em>User subclasses are not supported.</em> While clients may write
+ * subclasses, such code will not necessarily work and will not be
+ * guaranteed to work stably from release to release.
+ *
  * @stable ICU 2.0
  */
 class U_I18N_API NumberFormat : public Format {

icu4c/source/i18n/unicode/rbnf.h

@@ -457,6 +457,10 @@ class Collator;
  * <p>See the resource data and the demo program for annotated examples of real rule sets
  * using these features.</p>
  *
+ * <p><em>User subclasses are not supported.</em> While clients may write
+ * subclasses, such code will not necessarily work and will not be
+ * guaranteed to work stably from release to release.
+ *
  * @author Richard Gillam
  * @see NumberFormat
  * @see DecimalFormat

icu4c/source/i18n/unicode/smpdtfmt.h

@@ -191,6 +191,10 @@ class DateFormat;
  * year, whether hours are zero based or not (0 vs 12 or 24), and the timezone.
  * There is one common number format to handle all the numbers; the digit count
  * is handled programmatically according to the pattern.
+ *
+ * <p><em>User subclasses are not supported.</em> While clients may write
+ * subclasses, such code will not necessarily work and will not be
+ * guaranteed to work stably from release to release.
  */
 class U_I18N_API SimpleDateFormat: public DateFormat {
 public: