Remove unused EpochMillisDateFormatter (#37293)

This class has been superceded by a custom java time epoch millis date
parser.

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

@@ -1,119 +0,0 @@
-/*
- * 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.math.BigDecimal;
-import java.time.Instant;
-import java.time.ZoneId;
-import java.time.ZoneOffset;
-import java.time.format.DateTimeParseException;
-import java.time.temporal.TemporalAccessor;
-import java.util.Locale;
-import java.util.regex.Pattern;
-
-/**
- * This is a special formatter to parse the milliseconds since the epoch.
- * There is no way using a native java time date formatter to resemble
- * the required behaviour to parse negative milliseconds as well.
- *
- * This implementation simply tries to convert the input to a long and uses
- * this as the milliseconds since the epoch without involving any other
- * java time code
- */
-class EpochMillisDateFormatter implements DateFormatter {
-
-    private static final Pattern SPLIT_BY_DOT_PATTERN = Pattern.compile("\\.");
-    static final DateFormatter INSTANCE = new EpochMillisDateFormatter();
-    static final DateMathParser DATE_MATH_INSTANCE = new JavaDateMathParser(INSTANCE, INSTANCE);
-
-    private EpochMillisDateFormatter() {
-    }
-
-    @Override
-    public TemporalAccessor parse(String input) {
-        try {
-            if (input.contains(".")) {
-                String[] inputs = SPLIT_BY_DOT_PATTERN.split(input, 2);
-                Long milliSeconds = Long.valueOf(inputs[0]);
-                if (inputs[1].length() == 0) {
-                    // this is BWC compatible to joda time, nothing after the dot is allowed
-                    return Instant.ofEpochMilli(milliSeconds).atZone(ZoneOffset.UTC);
-                }
-                // scientific notation it is!
-                if (inputs[1].contains("e")) {
-                    return Instant.ofEpochMilli(Double.valueOf(input).longValue()).atZone(ZoneOffset.UTC);
-                }
-
-                if (inputs[1].length() > 6) {
-                    throw new DateTimeParseException("too much granularity after dot [" + input + "]", input, 0);
-                }
-                Long nanos = new BigDecimal(inputs[1]).movePointRight(6 - inputs[1].length()).longValueExact();
-                if (milliSeconds < 0) {
-                    nanos = nanos * -1;
-                }
-                return Instant.ofEpochMilli(milliSeconds).plusNanos(nanos).atZone(ZoneOffset.UTC);
-            } else {
-                return Instant.ofEpochMilli(Long.valueOf(input)).atZone(ZoneOffset.UTC);
-            }
-        } catch (NumberFormatException e) {
-            throw new DateTimeParseException("invalid number [" + input + "]", input, 0, e);
-        }
-    }
-    @Override
-    public DateFormatter withZone(ZoneId zoneId) {
-        if (ZoneOffset.UTC.equals(zoneId) == false) {
-            throw new IllegalArgumentException(pattern() + " date formatter can only be in zone offset UTC");
-        }
-        return INSTANCE;
-    }
-
-    @Override
-    public DateFormatter withLocale(Locale locale) {
-        if (Locale.ROOT.equals(locale) == false) {
-            throw new IllegalArgumentException(pattern() + " date formatter can only be in locale ROOT");
-        }
-        return this;
-    }
-
-    @Override
-    public String format(TemporalAccessor accessor) {
-        return String.valueOf(Instant.from(accessor).toEpochMilli());
-    }
-
-    @Override
-    public String pattern() {
-        return "epoch_millis";
-    }
-
-    @Override
-    public Locale locale() {
-        return Locale.ROOT;
-    }
-
-    @Override
-    public ZoneId zone() {
-        return ZoneOffset.UTC;
-    }
-
-    @Override
-    public DateMathParser toDateMathParser() {
-        return DATE_MATH_INSTANCE;
-    }
-}