org.apache.commons.lang3.time.FastTimeZone Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF 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.apache.commons.lang3.time;
import java.util.TimeZone;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* Faster methods to produce custom time zones.
*
* @since 3.7
*/
public class FastTimeZone {
private static final Pattern GMT_PATTERN = Pattern.compile("^(?:(?i)GMT)?([+-])?(\\d\\d?)?(:?(\\d\\d?))?$");
private static final TimeZone GREENWICH = new GmtTimeZone(false, 0, 0);
/**
* Gets the GMT TimeZone.
* @return A TimeZone with a raw offset of zero.
*/
public static TimeZone getGmtTimeZone() {
return GREENWICH;
}
/**
* Gets a TimeZone with GMT offsets. A GMT offset must be either 'Z', or 'UTC', or match
* (GMT)? hh?(:?mm?)?, where h and m are digits representing hours and minutes.
*
* @param pattern The GMT offset
* @return A TimeZone with offset from GMT or null, if pattern does not match.
*/
public static TimeZone getGmtTimeZone(final String pattern) {
if ("Z".equals(pattern) || "UTC".equals(pattern)) {
return GREENWICH;
}
final Matcher m = GMT_PATTERN.matcher(pattern);
if (m.matches()) {
final int hours = parseInt(m.group(2));
final int minutes = parseInt(m.group(4));
if (hours == 0 && minutes == 0) {
return GREENWICH;
}
return new GmtTimeZone(parseSign(m.group(1)), hours, minutes);
}
return null;
}
/**
* Gets a TimeZone, looking first for GMT custom ids, then falling back to Olson ids.
* A GMT custom id can be 'Z', or 'UTC', or has an optional prefix of GMT,
* followed by sign, hours digit(s), optional colon(':'), and optional minutes digits.
* i.e. [GMT] (+|-) Hours [[:] Minutes]
*
* @param id A GMT custom id (or Olson id
* @return A time zone
*/
public static TimeZone getTimeZone(final String id) {
final TimeZone tz = getGmtTimeZone(id);
if (tz != null) {
return tz;
}
return TimeZone.getTimeZone(id);
}
private static int parseInt(final String group) {
return group != null ? Integer.parseInt(group) : 0;
}
private static boolean parseSign(final String group) {
return group != null && group.charAt(0) == '-';
}
// do not instantiate
private FastTimeZone() {
}
}