LANG-1192 partial: implement format 'u' for FastDateFormat, day number of week

src/main/java/org/apache/commons/lang3/time/FastDateParser.java

@@ -601,6 +601,8 @@ private Strategy getStrategy(char f, int width, final Calendar definingCalendar)
             return MINUTE_STRATEGY;
         case 's':
             return SECOND_STRATEGY;
+        case 'u':
+            return DAY_OF_WEEK_STRATEGY;
         case 'w':
             return WEEK_OF_YEAR_STRATEGY;
         case 'y':
@@ -941,6 +943,12 @@ int modify(FastDateParser parser, final int iValue) {
     private static final Strategy WEEK_OF_MONTH_STRATEGY = new NumberStrategy(Calendar.WEEK_OF_MONTH);
     private static final Strategy DAY_OF_YEAR_STRATEGY = new NumberStrategy(Calendar.DAY_OF_YEAR);
     private static final Strategy DAY_OF_MONTH_STRATEGY = new NumberStrategy(Calendar.DAY_OF_MONTH);
+    private static final Strategy DAY_OF_WEEK_STRATEGY = new NumberStrategy(Calendar.DAY_OF_WEEK) {
+        @Override
+        int modify(FastDateParser parser, final int iValue) {
+            return iValue != 7 ? iValue + 1 : Calendar.SUNDAY;
+        }
+    };
     private static final Strategy DAY_OF_WEEK_IN_MONTH_STRATEGY = new NumberStrategy(Calendar.DAY_OF_WEEK_IN_MONTH);
     private static final Strategy HOUR_OF_DAY_STRATEGY = new NumberStrategy(Calendar.HOUR_OF_DAY);
     private static final Strategy HOUR24_OF_DAY_STRATEGY = new NumberStrategy(Calendar.HOUR_OF_DAY) {

src/main/java/org/apache/commons/lang3/time/FastDatePrinter.java

@@ -249,6 +249,9 @@ protected List<Rule> parsePattern() {
             case 'E': // day in week (text)
                 rule = new TextField(Calendar.DAY_OF_WEEK, tokenLen < 4 ? shortWeekdays : weekdays);
                 break;
+            case 'u': // day in week (number)
+                rule = new DayInWeekField(selectNumberRule(Calendar.DAY_OF_WEEK, tokenLen));
+                break;
             case 'D': // day in year (number)
                 rule = selectNumberRule(Calendar.DAY_OF_YEAR, tokenLen);
                 break;
@@ -1172,6 +1175,33 @@ public void appendTo(final Appendable buffer, final int value) throws IOExceptio
         }
     }
 
+    /**
+     * <p>Inner class to output the numeric day in week.</p>
+     */
+    private static class DayInWeekField implements NumberRule {
+        private final NumberRule mRule;
+
+        DayInWeekField(final NumberRule rule) {
+            mRule = rule;
+        }
+
+        @Override
+        public int estimateLength() {
+            return mRule.estimateLength();
+        }
+
+        @Override
+        public void appendTo(final Appendable buffer, final Calendar calendar) throws IOException {
+            int value = calendar.get(Calendar.DAY_OF_WEEK);
+            mRule.appendTo(buffer, value != Calendar.SUNDAY ? value - 1 : 7);
+        }
+
+        @Override
+        public void appendTo(final Appendable buffer, final int value) throws IOException {
+            mRule.appendTo(buffer, value);
+        }
+    }
+
     //-----------------------------------------------------------------------
 
     private static final ConcurrentMap<TimeZoneDisplayKey, String> cTimeZoneDisplayCache =

src/test/java/org/apache/commons/lang3/time/FastDateParserTest.java

@@ -702,4 +702,19 @@ public void testParseOffset() throws ParseException {
         cal.set(2015, Calendar.JULY, 4);
         Assert.assertEquals(cal.getTime(), date);
     }
+
+    @Test
+    public void testDayNumberOfWeek() throws ParseException {
+        final DateParser parser = getInstance("u");
+        Calendar calendar = Calendar.getInstance();
+
+        calendar.setTime(parser.parse("1"));
+        Assert.assertEquals(Calendar.MONDAY, calendar.get(Calendar.DAY_OF_WEEK));
+
+        calendar.setTime(parser.parse("6"));
+        Assert.assertEquals(Calendar.SATURDAY, calendar.get(Calendar.DAY_OF_WEEK));
+
+        calendar.setTime(parser.parse("7"));
+        Assert.assertEquals(Calendar.SUNDAY, calendar.get(Calendar.DAY_OF_WEEK));
+    }
 }

src/test/java/org/apache/commons/lang3/time/FastDatePrinterTest.java

@@ -420,4 +420,19 @@ public void testAppendableOptions() {
         long epoch = date.getTime();
         assertEquals(expected, format.format(epoch, sb).toString());
     }
+
+    @Test
+    public void testDayNumberOfWeek() {
+        final DatePrinter printer = getInstance("u");
+        Calendar calendar = Calendar.getInstance();
+
+        calendar.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);
+        assertEquals("1", printer.format(calendar.getTime()));
+
+        calendar.set(Calendar.DAY_OF_WEEK, Calendar.SATURDAY);
+        assertEquals("6", printer.format(calendar.getTime()));
+
+        calendar.set(Calendar.DAY_OF_WEEK, Calendar.SUNDAY);
+        assertEquals("7", printer.format(calendar.getTime()));
+    }
 }