Set start of the week to Monday for root locale (elastic#43652)

Introducing a IsoLocal.ROOT constant which should be used instead of java.util.Locale.ROOT in ES when dealing with dates. IsoLocal.ROOT  customises start of the week to be Monday instead of Sunday.

closes elastic#42588 an issue with investigation details
relates elastic#41670 bug raised (this won't fix it on its own. joda.parseInto has to be reimplemented
closes elastic#43275 an issue raised by community member

change skip reason

compile error

not orking spi

working unit test

cleanup

 change providers for 9+

revert changes IsoLocale

cleanup

move spi files to server

make unit test pass from gradle

expermienting with gradle tasks

uncomment jar hell check

only add settings in buildplugin

allign options for locale providers

buildSrc/src/main/groovy/org/elasticsearch/gradle/test/RestIntegTestTask.groovy

@@ -24,6 +24,7 @@ import org.elasticsearch.gradle.testclusters.RestTestRunnerTask
 import org.elasticsearch.gradle.tool.Boilerplate
 import org.elasticsearch.gradle.tool.ClasspathUtils
 import org.gradle.api.DefaultTask
+import org.gradle.api.JavaVersion
 import org.gradle.api.Task
 import org.gradle.api.file.FileCopyDetails
 import org.gradle.api.tasks.Copy

rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/310_date_agg_per_day_of_week.yml

@@ -0,0 +1,47 @@
+---
+setup:
+  - skip:
+      version: " - 7.3.99"
+      reason:  "only backported to 7.4 (7x)"
+
+  - do:
+        indices.create:
+          index: test
+          body:
+              mappings:
+                properties:
+                  date:
+                    type: date
+
+  - do:
+      index:
+        index: test
+        id:    1
+        body:  { "date": "2009-11-15T14:12:12" }
+
+  - do:
+      indices.refresh:
+        index: [test]
+
+---
+# The inserted document has a field date=2009-11-15T14:12:12 which is Sunday.
+# When aggregating per day of the week this should be considered as last day of the week (7)
+# and this value should be used in 'key_as_string'
+"Date aggregartion per day of week":
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        index: test
+        body:
+          aggregations:
+            test:
+              "date_histogram": {
+                "field": "date",
+                "calendar_interval": "day",
+                "format": "e",
+                "offset": 0
+              }
+
+  - match: {hits.total: 1}
+  - length: { aggregations.test.buckets: 1 }
+  - match: { aggregations.test.buckets.0.key_as_string: "7" }

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

@@ -0,0 +1,41 @@
+/*
+ * 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.util.Calendar;
+import java.util.Locale;
+import java.util.spi.CalendarDataProvider;
+
+public class IsoCalendarDataProvider extends CalendarDataProvider {
+
+    @Override
+    public int getFirstDayOfWeek(Locale locale) {
+        return Calendar.MONDAY;
+    }
+
+    @Override
+    public int getMinimalDaysInFirstWeek(Locale locale) {
+        return 4;
+    }
+
+    @Override
+    public Locale[] getAvailableLocales() {
+        return new Locale[]{Locale.ROOT};
+    }
+}

server/src/main/resources/META-INF/services/java.util.spi.CalendarDataProvider

@@ -0,0 +1 @@
+org.elasticsearch.common.time.IsoCalendarDataProvider

server/src/test/java/org/elasticsearch/common/joda/JavaJodaTimeDuellingTests.java

@@ -27,6 +27,7 @@
 import org.elasticsearch.test.ESTestCase;
 import org.joda.time.DateTime;
 import org.joda.time.DateTimeZone;
+import org.joda.time.format.DateTimeFormat;
 import org.joda.time.format.ISODateTimeFormat;
 
 import java.time.LocalDateTime;