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/*
* Copyright © 2018 The GWT Authors
*
* Licensed 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.gwtproject.i18n.client;
import elemental2.core.JsArray;
import java.util.Date;
/**
* The TimeZone class implements a time zone information source for client applications. The time
* zone object is instantiated from a TimeZoneData object, which is made from a JSON string that
* contains all the data needed for the specified time zone. Applications can instantiate a time
* zone statically, in which case the data could be retrieved from the {@link
* org.gwtproject.i18n.client.constants.TimeZoneConstants TimeZoneConstants} class. Applications can
* also choose to instantiate from a string obtained from a server. The time zone string contains
* locale specific data. If the application only uses a short representation, the English data will
* usually satisfy the user's need. In the case that only the time zone offset is known, there is a
* decent fallback that only uses the time zone offset to create a TimeZone object.
*/
public class TimeZone implements org.gwtproject.i18n.shared.TimeZone {
// constants to reference time zone names in the time zone names array
private static final int STD_SHORT_NAME = 0;
private static final int STD_LONG_NAME = 1;
private static final int DLT_SHORT_NAME = 2;
private static final int DLT_LONG_NAME = 3;
/**
* This factory method provides a decent fallback to create a time zone object just based on a
* given time zone offset.
*
* @param timeZoneOffsetInMinutes time zone offset in minutes
* @return a new time zone object
*/
public static TimeZone createTimeZone(int timeZoneOffsetInMinutes) {
TimeZone tz = new TimeZone();
tz.standardOffset = timeZoneOffsetInMinutes;
tz.timezoneID = composePOSIXTimeZoneID(timeZoneOffsetInMinutes);
tz.tzNames = new String[2];
tz.tzNames[0] = composeUTCString(timeZoneOffsetInMinutes);
tz.tzNames[1] = composeUTCString(timeZoneOffsetInMinutes);
tz.transitionPoints = null;
tz.adjustments = null;
return tz;
}
/**
* This factory method creates a time zone instance from a JSON string that contains the time zone
* information for desired time zone. Applications can get such a string from the
* TimeZoneConstants class, or it can request the string from the server. Either way, the
* application obtains the original string from the data provided in the
* TimeZoneConstant.properties file, which was carefully prepared from CLDR and Olson time zone
* database.
*
* @param tzJSON JSON string that contains time zone data
* @return a new time zone object
*/
public static TimeZone createTimeZone(String tzJSON) {
TimeZoneInfo tzData = TimeZoneInfo.buildTimeZoneData(tzJSON);
return createTimeZone(tzData);
}
public static TimeZone createTimeZone(TimeZoneInfo timezoneData) {
TimeZone tz = new TimeZone();
tz.timezoneID = timezoneData.getID();
tz.standardOffset = -timezoneData.getStandardOffset();
JsArray jsTimezoneNames = timezoneData.getNames();
tz.tzNames = new String[jsTimezoneNames.length];
for (int i = 0; i < jsTimezoneNames.length; i++) {
tz.tzNames[i] = jsTimezoneNames.getAt(i);
}
JsArray transitions = timezoneData.getTransitions();
if (transitions == null || transitions.length == 0) {
tz.transitionPoints = null;
tz.adjustments = null;
} else {
int transitionNum = transitions.length / 2;
tz.transitionPoints = new int[transitionNum];
tz.adjustments = new int[transitionNum];
for (int i = 0; i < transitionNum; ++i) {
tz.transitionPoints[i] = transitions.getAt(i * 2);
tz.adjustments[i] = transitions.getAt(i * 2 + 1);
}
}
return tz;
}
/**
* In GMT representation, +/- has reverse sign of time zone offset. when offset == 480, it should
* output GMT-08:00.
*/
private static String composeGMTString(int offset) {
char data[] = {'G', 'M', 'T', '-', '0', '0', ':', '0', '0'};
if (offset <= 0) {
data[3] = '+';
offset = -offset; // suppress the '-' sign for text display.
}
data[4] = (char) (data[4] + (offset / 60) / 10);
data[5] = (char) (data[5] + (offset / 60) % 10);
data[7] = (char) (data[7] + (offset % 60) / 10);
data[8] = (char) (data[8] + offset % 10);
return new String(data);
}
/** POSIX time zone ID as fallback. */
private static String composePOSIXTimeZoneID(int offset) {
if (offset == 0) {
return "Etc/GMT";
}
String str;
if (offset < 0) {
offset = -offset;
str = "Etc/GMT-";
} else {
str = "Etc/GMT+";
}
return str + offsetDisplay(offset);
}
private static String composeUTCString(int offset) {
if (offset == 0) {
return "UTC";
}
String str;
if (offset < 0) {
offset = -offset;
str = "UTC+";
} else {
str = "UTC-";
}
return str + offsetDisplay(offset);
}
private static String offsetDisplay(int offset) {
int hour = offset / 60;
int mins = offset % 60;
if (mins == 0) {
return Integer.toString(hour);
}
return Integer.toString(hour) + ":" + Integer.toString(mins);
}
private String timezoneID;
private int standardOffset;
private String[] tzNames;
private int[] transitionPoints;
private int[] adjustments;
private TimeZone() {}
/* (non-Javadoc)
* @see org.gwtproject.i18n.client.TimeZoneIntf#getDaylightAdjustment(java.util.Date)
*/
@Override
public int getDaylightAdjustment(Date date) {
if (transitionPoints == null) {
return 0;
}
long timeInHours = date.getTime() / 1000 / 3600;
int index = 0;
while (index < transitionPoints.length && timeInHours >= transitionPoints[index]) {
++index;
}
return (index == 0) ? 0 : adjustments[index - 1];
}
/* (non-Javadoc)
* @see org.gwtproject.i18n.client.TimeZoneIntf#getGMTString(java.util.Date)
*/
@Override
public String getGMTString(Date date) {
return composeGMTString(getOffset(date));
}
/* (non-Javadoc)
* @see org.gwtproject.i18n.client.TimeZoneIntf#getID()
*/
@Override
public String getID() {
return timezoneID;
}
/* (non-Javadoc)
* @see org.gwtproject.i18n.client.TimeZoneIntf#getISOTimeZoneString(java.util.Date)
*/
@Override
public String getISOTimeZoneString(Date date) {
int offset = -getOffset(date);
char data[] = {'+', '0', '0', ':', '0', '0'};
if (offset < 0) {
data[0] = '-';
offset = -offset; // suppress the '-' sign for text display.
}
data[1] = (char) (data[1] + (offset / 60) / 10);
data[2] = (char) (data[2] + (offset / 60) % 10);
data[4] = (char) (data[4] + (offset % 60) / 10);
data[5] = (char) (data[5] + offset % 10);
return new String(data);
}
/* (non-Javadoc)
* @see org.gwtproject.i18n.client.TimeZoneIntf#getLongName(java.util.Date)
*/
@Override
public String getLongName(Date date) {
return tzNames[isDaylightTime(date) ? DLT_LONG_NAME : STD_LONG_NAME];
}
/* (non-Javadoc)
* @see org.gwtproject.i18n.client.TimeZoneIntf#getOffset(java.util.Date)
*/
@Override
public int getOffset(Date date) {
return standardOffset - getDaylightAdjustment(date);
}
/* (non-Javadoc)
* @see org.gwtproject.i18n.client.TimeZoneIntf#getRFCTimeZoneString(java.util.Date)
*/
@Override
public String getRFCTimeZoneString(Date date) {
int offset = -getOffset(date);
char data[] = {'+', '0', '0', '0', '0'};
if (offset < 0) {
data[0] = '-';
offset = -offset; // suppress the '-' sign for text display.
}
data[1] = (char) (data[1] + (offset / 60) / 10);
data[2] = (char) (data[2] + (offset / 60) % 10);
data[3] = (char) (data[3] + (offset % 60) / 10);
data[4] = (char) (data[4] + offset % 10);
return new String(data);
}
/* (non-Javadoc)
* @see org.gwtproject.i18n.client.TimeZoneIntf#getShortName(java.util.Date)
*/
@Override
public String getShortName(Date date) {
return tzNames[isDaylightTime(date) ? DLT_SHORT_NAME : STD_SHORT_NAME];
}
/* (non-Javadoc)
* @see org.gwtproject.i18n.client.TimeZoneIntf#getStandardOffset()
*/
@Override
public int getStandardOffset() {
return standardOffset;
}
/* (non-Javadoc)
* @see org.gwtproject.i18n.client.TimeZoneIntf#isDaylightTime(java.util.Date)
*/
@Override
public boolean isDaylightTime(Date date) {
return getDaylightAdjustment(date) > 0;
}
}