Better exception messages from FastDateParser.parse(String)

Author: garydgregory

src/changes/changes.xml

@@ -98,6 +98,7 @@ The <action> type attribute can be add,update,fix,remove.
     <action                   type="fix" dev="ggregory" due-to="Gary Gregory, David Du">Simplify literal assignments in ArrayFillTest #1567.</action>
     <action                   type="fix" dev="ggregory" due-to="Gary Gregory, David Du">Make ArrayUtils methods implementation consistent with other overloads #1568.</action>
     <action                   type="fix" dev="ggregory" due-to="ThrawnCA, Gary Gregory">Fix handling of null marker in StringUtils.abbreviate(String, String, int, int) #1571.</action>
+    <action                   type="fix" dev="ggregory" due-to="Gary Gregory">Better exception messages from FastDateParser.parse(String).</action>
     <!-- ADD -->
     <action                   type="add" dev="ggregory" due-to="Gary Gregory">Add JavaVersion.JAVA_27.</action>
     <action                   type="add" dev="ggregory" due-to="Gary Gregory">Add SystemUtils.IS_JAVA_27.</action>

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

@@ -47,6 +47,7 @@
 import org.apache.commons.lang3.ArraySorter;
 import org.apache.commons.lang3.CharUtils;
 import org.apache.commons.lang3.LocaleUtils;
+import org.apache.commons.lang3.StringUtils;
 
 /**
  * FastDateParser is a fast and thread-safe version of {@link java.text.SimpleDateFormat}.
@@ -323,7 +324,7 @@ boolean parse(final FastDateParser parser, final Calendar calendar, final String
          */
         @Override
         public String toString() {
-            return "NumberStrategy [field=" + field + "]";
+            return getClass().getSimpleName() + " [field=" + field + "]";
         }
     }
 
@@ -1027,11 +1028,12 @@ public Date parse(final String source) throws ParseException {
         final Date date = parse(source, pp);
         if (date == null) {
             // Add a note regarding supported date range
+            final int errorIndex = pp.getErrorIndex();
+            final String msg = String.format("Unparseable date: '%s', parse position = %s", source, pp);
             if (locale.equals(JAPANESE_IMPERIAL)) {
-                throw new ParseException("(The " + locale + " locale does not support dates before 1868 AD)\nUnparseable date: \"" + source,
-                        pp.getErrorIndex());
+                throw new ParseException(String.format("; the %s locale does not support dates before 1868-01-01.", locale, msg), errorIndex);
             }
-            throw new ParseException("Unparseable date: " + source, pp.getErrorIndex());
+            throw new ParseException(msg, errorIndex);
         }
         return date;
     }
@@ -1129,6 +1131,6 @@ public String toString() {
      */
     public String toStringAll() {
         return "FastDateParser [pattern=" + pattern + ", timeZone=" + timeZone + ", locale=" + locale + ", century=" + century + ", startYear=" + startYear
-                + ", patterns=" + patterns + "]";
+                + ", patterns=" + StringUtils.join(patterns, ", " + System.lineSeparator() + "\t") + "]";
     }
 }