Add plusDays method for RDate

src/main/java/com/github/jarnaud/republican/RDate.java

@@ -1,12 +1,19 @@
 package com.github.jarnaud.republican;
 
+import java.time.LocalDate;
 import java.util.Objects;
 
 /**
  * A Republican local date.
  */
 public final class RDate implements Comparable<RDate> {
 
+    /**
+     * The first day in the Republican calendar (corresponding Republican day would be An 1 Vendemiaire 1).
+     * Dates before this date are undefined in the Republican calendar.
+     */
+    public static final LocalDate FIRST_DAY = LocalDate.of(1792, 9, 22);
+
     private final int year;
     private final RMonth month;
     private final int decade;
@@ -30,13 +37,37 @@ private int processDecade(int day) {
      *
      * @param year  the Republican year (eg. An XII).
      * @param month the Republican month.
-     * @param day   the Republican day in the month.
+     * @param day   the Republican day in the month, must be:
+     *              - between 1 and 30 for normal months.
+     *              - between 1 and 5 for Sanculottide on normal years.
+     *              - between 1 and 6 for Sanculottide on sextile years.
      * @return the Republican date.
      */
     public static RDate of(int year, RMonth month, int day) {
+        if (year < 1 || month == null || day < 1 || day > 30 || (month == RMonth.Sanculottide && day > 6)) {
+            throw new RuntimeException("Invalid parameters for building Republican date");
+        }
         return new RDate(year, month, day);
     }
 
+    /**
+     * Construct a new Republican date.
+     *
+     * @param year  the Republican year (eg. An XII).
+     * @param month the Republican month number, between 1 (for Vendemiaire) and 13 (for Sanculottide).
+     * @param day   the Republican day in the month, must be:
+     *              - between 1 and 30 for normal months.
+     *              - between 1 and 5 for Sanculottide on normal years.
+     *              - between 1 and 6 for Sanculottide on sextile years.
+     * @return the Republican date.
+     */
+    public static RDate of(int year, int month, int day) {
+        if (year < 1 || month < 1 || month > 13 || day < 1 || day > 30 || (month == 13 && day > 6)) {
+            throw new RuntimeException("Invalid parameters for building Republican date");
+        }
+        return new RDate(year, RMonth.values()[month - 1], day);
+    }
+
     public int getYear() {
         return year;
     }
@@ -91,19 +122,6 @@ public int hashCode() {
         return Objects.hash(year, month, decade, day);
     }
 
-    /**
-     * Return a copy of this date shifted by the given number of days.
-     * <p>
-     * TODO used by converter for shifting by 1 or 2 days within a month,
-     * TODO will need to handle month/year shift before being made public.
-     *
-     * @param daysToAdd the number of days to add.
-     * @return the new date.
-     */
-    RDate plusDays(int daysToAdd) {
-        return RDate.of(this.getYear(), this.getMonth(), this.getDay() + daysToAdd);
-    }
-
     public boolean isBefore(RDate date) {
         if (year != date.getYear()) return year < date.getYear();
         if (month.ordinal() != date.getMonth().ordinal()) return month.ordinal() < date.getMonth().ordinal();
@@ -122,4 +140,22 @@ public boolean isSextile() {
         return year >= 20 && year % 4 == 0 && (year % 100 != 0 || year % 400 == 0);
     }
 
+    /**
+     * Return a copy of this date shifted by the given number of days.
+     * Cannot go back before the first day of the Republican calendar (1792-09-22).
+     * <p>
+     * Uses converters to go through LocalDate implementation of plusDays.
+     *
+     * @param daysToAdd the number of days to add.
+     * @return the new date.
+     */
+    public RDate plusDays(int daysToAdd) {
+        LocalDate gregorianDate = new RGConverter().convert(this);
+        gregorianDate = gregorianDate.plusDays(daysToAdd);
+        if (gregorianDate.isBefore(FIRST_DAY)) {
+            throw new RuntimeException("Date " + gregorianDate + " is undefined in the Republican calendar.");
+        }
+        return new GRConverter().convert(gregorianDate);
+    }
+
 }

src/main/java/com/github/jarnaud/republican/RGConverter.java

@@ -57,7 +57,19 @@ private int getDaysSinceRYearStart(RDate rDate) {
      */
     private RDate getGregorianYearStartDay(int rYear) {
         RDate start = RDate.of(rYear, RMonth.Nivose, 12);
-        return start.plusDays(processShifts(rYear - 1));
+        return plusDays(start, processShifts(rYear - 1));
+    }
+
+    /**
+     * Return a copy of this date shifted by the given number of days.
+     * NB: used only by this converter for shifting by 1 or 2 days within a month (month/year shifts are not handled).
+     * Do not use as actual plus to add days on production dates
+     *
+     * @param daysToAdd the number of days to add.
+     * @return the new date.
+     */
+    private RDate plusDays(RDate date, int daysToAdd) {
+        return RDate.of(date.getYear(), date.getMonth(), date.getDay() + daysToAdd);
     }
 
     /**

src/test/java/com/github/jarnaud/republican/RDateTest.java

@@ -6,6 +6,21 @@
 
 public class RDateTest {
 
+    @Test
+    public void testOf1() {
+        assertEquals(RMonth.Vendemiaire, RDate.of(1, RMonth.Vendemiaire, 1).getMonth());
+        assertThrows(RuntimeException.class, () -> RDate.of(1, null, 1));
+        assertThrows(RuntimeException.class, () -> RDate.of(-5, null, 1));
+        assertThrows(RuntimeException.class, () -> RDate.of(12, RMonth.Sanculottide, 7));
+    }
+
+    @Test
+    public void testOf2() {
+        assertEquals(RMonth.Vendemiaire, RDate.of(1, 1, 1).getMonth());
+        assertThrows(RuntimeException.class, () -> RDate.of(1, 0, 1));
+        assertEquals(RDate.of(58, RMonth.Floreal, 1), RDate.of(58, 8, 1));
+    }
+
     @Test
     public void testDecade() {
         assertEquals(1, RDate.of(6, RMonth.Floreal, 1).getDecade());
@@ -20,7 +35,7 @@ public void testDecade() {
     }
 
     @Test
-    public void isBeforeTest() {
+    public void testIsBefore() {
         RDate d1 = RDate.of(6, RMonth.Floreal, 4);
         RDate d2 = RDate.of(6, RMonth.Floreal, 5);
         assertTrue(d1.isBefore(d2));
@@ -29,7 +44,7 @@ public void isBeforeTest() {
     }
 
     @Test
-    public void isSextileTest() {
+    public void testIsSextile() {
         assertFalse(RDate.of(1, RMonth.Floreal, 4).isSextile());
         assertFalse(RDate.of(2, RMonth.Floreal, 4).isSextile());
         assertTrue(RDate.of(3, RMonth.Floreal, 4).isSextile());
@@ -41,4 +56,9 @@ public void isSextileTest() {
         assertFalse(RDate.of(300, RMonth.Floreal, 4).isSextile());
         assertTrue(RDate.of(400, RMonth.Floreal, 4).isSextile());
     }
+
+    @Test
+    public void testPlusDays() {
+        assertEquals(RDate.of(1, 1, 1), RDate.of(1, 1, 1).plusDays(0));
+    }
 }