Add method that parses dates without throwing exceptions

server/src/main/java/org/elasticsearch/common/time/DateFormatter.java

@@ -18,6 +18,7 @@
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Locale;
+import java.util.Optional;
 
 public interface DateFormatter {
 
@@ -30,6 +31,14 @@ public interface DateFormatter {
      */
     TemporalAccessor parse(String input);
 
+    /**
+     * Try to parse input to a java time TemporalAccessor
+     * @param input An arbitrary string resembling the string representation of a date or time
+     * @return      Tuple containing a boolean value indicating parsing success or failure and a java time object containing
+     * the parsed input in the case of successful parsing
+     */
+    Optional<TemporalAccessor> parseWithoutException(String input);
+
     /**
      * Parse the given input into millis-since-epoch.
      */

server/src/main/java/org/elasticsearch/common/time/JavaDateFormatter.java

@@ -27,6 +27,7 @@
 import java.util.Locale;
 import java.util.Map;
 import java.util.Objects;
+import java.util.Optional;
 import java.util.function.Consumer;
 import java.util.stream.Collectors;
 
@@ -176,6 +177,19 @@ public TemporalAccessor parse(String input) {
         }
     }
 
+    @Override
+    public Optional<TemporalAccessor> parseWithoutException(String input) {
+        for (DateTimeFormatter formatter : parsers) {
+            ParsePosition pos = new ParsePosition(0);
+            Object object = formatter.toFormat().parseObject(input, pos);
+            if (parsingSucceeded(object, input, pos)) {
+                return Optional.of((TemporalAccessor) object);
+            }
+        }
+
+        return Optional.empty();
+    }
+
     /**
      * Attempt parsing the input without throwing exception. If multiple parsers are provided,
      * it will continue iterating if the previous parser failed. The pattern must fully match, meaning whole input was used.

server/src/test/java/org/elasticsearch/common/time/DateFormattersTests.java

@@ -36,10 +36,19 @@
 public class DateFormattersTests extends ESTestCase {
 
     private void assertParseException(String input, String format) {
+        assertParseException(input, format, true);
+    }
+
+    private void assertParseException(String input, String format, boolean testParseWithoutException) {
+
         DateFormatter javaTimeFormatter = DateFormatter.forPattern(format);
         IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> javaTimeFormatter.parse(input));
         assertThat(e.getMessage(), containsString(input));
         assertThat(e.getMessage(), containsString(format));
+        if (testParseWithoutException) {
+            var result = javaTimeFormatter.parseWithoutException(input);
+            assertTrue(result.isEmpty());
+        }
     }
 
     private void assertParses(String input, String format) {
@@ -53,6 +62,11 @@ private void assertParses(String input, DateFormatter formatter) {
         ZonedDateTime zonedDateTime = DateFormatters.from(javaTimeAccessor);
 
         assertThat(zonedDateTime, notNullValue());
+
+        var result = formatter.parseWithoutException(input);
+        assertFalse(result.isEmpty());
+        ZonedDateTime zdt2 = DateFormatters.from(result.get());
+        assertThat(zonedDateTime, equalTo(zdt2));
     }
 
     private void assertDateMathEquals(String text, String pattern) {
@@ -426,8 +440,8 @@ public void testFractionalSeconds() {
     }
 
     public void testIncorrectFormat() {
-        assertParseException("2021-01-01T23-35-00Z", "strict_date_optional_time||epoch_millis");
-        assertParseException("2021-01-01T23-35-00Z", "strict_date_optional_time");
+        assertParseException("2021-01-01T23-35-00Z", "strict_date_optional_time||epoch_millis", false);
+        assertParseException("2021-01-01T23-35-00Z", "strict_date_optional_time", false);
     }
 
     public void testMinMillis() {