Date: Add DateFormatters class that uses java.time

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

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+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.elasticsearch.common.time;
+
+import java.time.ZoneId;
+import java.time.format.DateTimeFormatter;
+import java.time.format.DateTimeParseException;
+import java.time.temporal.TemporalAccessor;
+
+/**
+ * wrapper class around java.time.DateTimeFormatter that supports multiple formats for easier parsing,
+ * and one specific format for printing
+ */
+public class CompoundDateTimeFormatter {
+
+    final DateTimeFormatter printer;
+    final DateTimeFormatter[] parsers;
+
+    CompoundDateTimeFormatter(DateTimeFormatter ... parsers) {
+        if (parsers.length == 0) {
+            throw new IllegalArgumentException("at least one date time formatter is required");
+        }
+        this.printer = parsers[0];
+        this.parsers = parsers;
+    }
+
+    public TemporalAccessor parse(String input) {
+        DateTimeParseException failure = null;
+        for (int i = 0; i < parsers.length; i++) {
+            try {
+                return parsers[i].parse(input);
+            } catch (DateTimeParseException e) {
+                if (failure == null) {
+                    failure = e;
+                } else {
+                    failure.addSuppressed(e);
+                }
+            }
+        }
+
+        // ensure that all parsers exceptions are returned instead of only the last one
+        throw failure;
+    }
+
+    public CompoundDateTimeFormatter withZone(ZoneId zoneId) {
+        final DateTimeFormatter[] parsersWithZone = new DateTimeFormatter[parsers.length];
+        for (int i = 0; i < parsers.length; i++) {
+            parsersWithZone[i] = parsers[i].withZone(zoneId);
+        }
+
+        return new CompoundDateTimeFormatter(parsersWithZone);
+    }
+
+    public String format(TemporalAccessor accessor) {
+        return printer.format(accessor);
+    }
+}