CLDR-17851 fix for BH era

- BH, added in CLDR-18464, is out of order… attempt to find the prev and next era by date.

Author: srl295

tools/cldr-code/src/main/java/org/unicode/cldr/test/ExampleGenerator.java

@@ -3120,19 +3120,34 @@ private void handleEras(XPathParts parts, String value, List<String> examples) {
         if (eraData == null) {
             return; // no era data
         }
-        GregorianCalendar startCal = forDateString(eraData.getStart());
-        GregorianCalendar endCal = forDateString(eraData.getEnd());
+        GregorianCalendar startCal = eraData.getStartCalendar();
+        GregorianCalendar endCal = eraData.getEndCalendar();
 
-        final SupplementalCalendarData.EraData prevEra = calendarData.get(typeIndex - 1);
-        final SupplementalCalendarData.EraData nextEra = calendarData.get(typeIndex + 1);
+        final SupplementalCalendarData.EraData eminusone = calendarData.get(typeIndex - 1);
+        final SupplementalCalendarData.EraData eplusone = calendarData.get(typeIndex + 1);
+
+        SupplementalCalendarData.EraData prevEra = null;
+        SupplementalCalendarData.EraData nextEra = null;
+
+        // see if we can find the 'prev' and 'next' era by date
+        if (eminusone != null && eminusone.compareTo(eraData) < 0) {
+            prevEra = eminusone;
+        } else if (eplusone != null && eplusone.compareTo(eraData) < 0) {
+            prevEra = eplusone;
+        }
+        if (eminusone != null && eminusone.compareTo(eraData) > 0) {
+            nextEra = eminusone;
+        } else if (eplusone != null && eplusone.compareTo(eraData) > 0) {
+            nextEra = eplusone;
+        }
 
         if (startCal == null && prevEra != null && prevEra.getEnd() != null) {
-            startCal = forDateString(prevEra.getEnd());
+            startCal = prevEra.getEndCalendar();
             // shift forward so we are in the next era
             startCal.setTimeInMillis(startCal.getTimeInMillis() + (DateConstants.MILLIS_PER_DAY));
         }
         if (endCal == null && nextEra != null && nextEra.getStart() != null) {
-            endCal = forDateString(nextEra.getStart());
+            endCal = nextEra.getStartCalendar();
             // shift backward so we are in the prev era
             endCal.setTimeInMillis(endCal.getTimeInMillis() - (DateConstants.MILLIS_PER_DAY));
         }
@@ -3150,7 +3165,7 @@ private void handleEras(XPathParts parts, String value, List<String> examples) {
             sampleDate.setTimeInMillis(
                     sampleDate.getTimeInMillis() - (DateConstants.MILLIS_PER_DAY));
         } else if (startCal != null && endCal == null) {
-            sampleDate = forDateString("2002-07-15"); // CLDR repo root commit
+            sampleDate = new GregorianCalendar(2002, 6, 15); // CLDR repo root commit
             if (sampleDate.before(startCal)) {
                 sampleDate = startCal;
                 sampleDate.setTimeInMillis(
@@ -3183,24 +3198,6 @@ private void handleEras(XPathParts parts, String value, List<String> examples) {
         examples.add(sdf.format(sample));
     }
 
-    private GregorianCalendar forDateString(String ymd) {
-        if (ymd == null) return null;
-        int multiplier = 1;
-        if (ymd.startsWith("-")) {
-            multiplier = -1;
-            ymd = ymd.substring(1);
-        }
-        final String[] parts = ymd.split("-");
-        try {
-            return new GregorianCalendar(
-                    multiplier * Integer.parseInt(parts[0]),
-                    Integer.parseInt(parts[1]) - 1,
-                    Integer.parseInt(parts[2]));
-        } catch (NumberFormatException nfe) {
-            throw new IllegalArgumentException("While parsing date string " + ymd, nfe);
-        }
-    }
-
     /**
      * Add examples for quarters for the gregorian calendar, matching each quarter type (1, 2, 3, 4)
      * to a corresponding sample month and formatting an example with that date

tools/cldr-code/src/main/java/org/unicode/cldr/util/SupplementalCalendarData.java

@@ -1,6 +1,7 @@
 package org.unicode.cldr.util;
 
 import com.ibm.icu.impl.locale.XCldrStub.ImmutableMap;
+import com.ibm.icu.util.GregorianCalendar;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.Map;
@@ -10,7 +11,7 @@
 
 public class SupplementalCalendarData implements Iterable<String> {
     /** an <era> element */
-    public static class EraData {
+    public static class EraData implements Comparable<EraData> {
         static final int INDEX = 4; // index of our element
 
         /** the <era> xpath */
@@ -33,6 +34,14 @@ public String getEnd() {
             return xpath.getAttributeValue(INDEX, LDMLConstants.END);
         }
 
+        public GregorianCalendar getStartCalendar() {
+            return forDateString(getStart());
+        }
+
+        public GregorianCalendar getEndCalendar() {
+            return forDateString(getEnd());
+        }
+
         public String getCode() {
             return xpath.getAttributeValue(INDEX, LDMLConstants.CODE);
         }
@@ -49,6 +58,44 @@ public String toString() {
                     "ERA %d, [%s-%s] code=%s, aliases=%s",
                     getType(), getStart(), getEnd(), getCode(), String.join(",", getAliases()));
         }
+
+        private static final GregorianCalendar forDateString(String ymd) {
+            if (ymd == null) return null;
+            int multiplier = 1;
+            if (ymd.startsWith("-")) {
+                multiplier = -1;
+                ymd = ymd.substring(1);
+            }
+            final String[] parts = ymd.split("-");
+            try {
+                return new GregorianCalendar(
+                        multiplier * Integer.parseInt(parts[0]),
+                        Integer.parseInt(parts[1]) - 1,
+                        Integer.parseInt(parts[2]));
+            } catch (NumberFormatException nfe) {
+                throw new IllegalArgumentException("While parsing date string " + ymd, nfe);
+            }
+        }
+
+        private GregorianCalendar getLatest() {
+            GregorianCalendar l = getEndCalendar();
+            if (l == null) l = getStartCalendar();
+            return l;
+        }
+
+        /** only works within the same cal system */
+        @Override
+        public int compareTo(EraData o) {
+            final GregorianCalendar l = getLatest();
+            final GregorianCalendar ol = o.getLatest();
+            if (l == null || ol == null) {
+                // compare by id
+                return Integer.compare(getType(), o.getType());
+            } else {
+                // compare by date
+                return l.compareTo(ol);
+            }
+        }
     }
 
     /** a <calendar type=> element */