Java tutorial
/* * Copyright 2008 Google Inc. * * 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 com.google.gwt.i18n.shared.impl; import java.util.Date; /** * Implementation detail of DateTimeFormat -- not a public API and subject to * change. * * DateRecord class exposes almost the same set of interface as Date class with * only a few exceptions. The main purpose is the record all the information * during parsing phase and resolve them in a later time when all information * can be processed together. */ @SuppressWarnings("deprecation") public class DateRecord extends Date { /* * The serial version UID is only defined because this class is implicitly * serializable, causing warnings due to its absence. It will generally not be * used. */ private static final long serialVersionUID = -1278816193740448162L; public static final int AM = 0; public static final int PM = 1; private static final int JS_START_YEAR = 1900; private int era; private int year; private int month; private int dayOfMonth; private int ampm; private int hours; private int minutes; private int seconds; private int milliseconds; private int tzOffset; private int dayOfWeek; private boolean ambiguousYear; /** * Initialize DateExt object with default value. Here we use -1 for most of * the field to indicate that field is not set. */ public DateRecord() { era = -1; ambiguousYear = false; year = Integer.MIN_VALUE; month = -1; dayOfMonth = -1; ampm = -1; hours = -1; minutes = -1; seconds = -1; milliseconds = -1; dayOfWeek = -1; tzOffset = Integer.MIN_VALUE; } /** * calcDate uses all the field available so far to fill a Date object. For * those information that is not provided, the existing value in 'date' will * be kept. Ambiguous year will be resolved after the date/time values are * resolved. * * If the strict option is set to true, calcDate will calculate certain * invalid dates by wrapping around as needed. For example, February 30 will * wrap to March 2. * * @param date The Date object being filled. Its value should be set to an * acceptable default before pass in to this method * @param strict true to be strict when parsing * @return true if successful, otherwise false. */ public boolean calcDate(Date date, boolean strict) { // Year 0 is 1 BC, and so on. if (this.era == 0 && this.year > 0) { this.year = -(this.year - 1); } if (this.year > Integer.MIN_VALUE) { date.setYear(this.year - JS_START_YEAR); } // "setMonth" and "setDate" is a little bit tricky. Suppose content in // date is 11/30, switch month to 02 will lead to 03/02 since 02/30 does // not exist. And you certain won't like 02/12 turn out to be 03/12. So // here to set date to a smaller number before month, and later setMonth. // Real date is set after, and that might cause month switch. However, // that's desired. int orgDayOfMonth = date.getDate(); date.setDate(1); if (this.month >= 0) { date.setMonth(this.month); } if (this.dayOfMonth >= 0) { date.setDate(this.dayOfMonth); } else if (this.month >= 0) { // If the month was parsed but dayOfMonth was not, then the current day of // the month shouldn't affect the parsed month. For example, if "Feb2006" // is parse on January 31, the resulting date should be in February, not // March. So, we limit the day of the month to the maximum day within the // parsed month. Date tmp = new Date(date.getYear(), date.getMonth(), 35); int daysInCurrentMonth = 35 - tmp.getDate(); date.setDate(Math.min(daysInCurrentMonth, orgDayOfMonth)); } else { date.setDate(orgDayOfMonth); } // adjust ampm if (this.hours < 0) { this.hours = date.getHours(); } if (this.ampm > 0) { if (this.hours < 12) { this.hours += 12; } } date.setHours(this.hours); if (this.minutes >= 0) { date.setMinutes(this.minutes); } if (this.seconds >= 0) { date.setSeconds(this.seconds); } if (this.milliseconds >= 0) { date.setTime(date.getTime() / 1000 * 1000 + this.milliseconds); } // If strict, verify that the original date fields match the calculated date // fields. We do this before we set the timezone offset, which will skew all // of the dates. // // We don't need to check the day of week as it is guaranteed to be correct // or return false below. if (strict) { if ((this.year > Integer.MIN_VALUE) && ((this.year - JS_START_YEAR) != date.getYear())) { return false; } if ((this.month >= 0) && (this.month != date.getMonth())) { return false; } if ((this.dayOfMonth >= 0) && (this.dayOfMonth != date.getDate())) { return false; } // Times have well defined maximums if (this.hours >= 24) { return false; } if (this.minutes >= 60) { return false; } if (this.seconds >= 60) { return false; } if (this.milliseconds >= 1000) { return false; } } // Resolve ambiguous year if needed. if (this.ambiguousYear) { // the two-digit year == the default start year Date defaultCenturyStart = new Date(); defaultCenturyStart.setYear(defaultCenturyStart.getYear() - 80); if (date.before(defaultCenturyStart)) { date.setYear(defaultCenturyStart.getYear() + 100); } } // Date is resolved to the nearest dayOfWeek if date is not explicitly // specified. There is one exception, if the nearest dayOfWeek falls // into a different month, the 2nd nearest dayOfWeek, which is on the // other direction, will be used. if (this.dayOfWeek >= 0) { if (this.dayOfMonth == -1) { // Adjust to the nearest day of the week. int adjustment = (7 + this.dayOfWeek - date.getDay()) % 7; if (adjustment > 3) { adjustment -= 7; } int orgMonth = date.getMonth(); date.setDate(date.getDate() + adjustment); // If the nearest weekday fall into a different month, we will use the // 2nd nearest weekday, which will be on the other direction, and is // sure fall into the same month. if (date.getMonth() != orgMonth) { date.setDate(date.getDate() + (adjustment > 0 ? -7 : 7)); } } else { if (date.getDay() != this.dayOfWeek) { return false; } } } // Adjust time zone. if (this.tzOffset > Integer.MIN_VALUE) { int offset = date.getTimezoneOffset(); date.setTime(date.getTime() + (this.tzOffset - offset) * 60 * 1000); // HBJ date.setTime(date.getTime() + this.tzOffset * 60 * 1000); } return true; } /** * Set ambiguous year field. This flag indicates that a 2 digit years's * century need to be determined by its date/time value. This can only be * resolved after its date/time is known. * * @param ambiguousYear true if it is ambiguous year. */ public void setAmbiguousYear(boolean ambiguousYear) { this.ambiguousYear = ambiguousYear; } /** * Set morning/afternoon field. * * @param ampm ampm value. */ public void setAmpm(int ampm) { this.ampm = ampm; } /** * Set dayOfMonth field. * * @param day dayOfMonth value */ public void setDayOfMonth(int day) { this.dayOfMonth = day; } /** * Set dayOfWeek field. * * @param dayOfWeek day of the week. */ public void setDayOfWeek(int dayOfWeek) { this.dayOfWeek = dayOfWeek; } /** * Set Era field. * * @param era era value being set. */ public void setEra(int era) { this.era = era; } /** * Set hour field. * * @param hours hour value. */ @Override public void setHours(int hours) { this.hours = hours; } /** * Set milliseconds field. * * @param milliseconds milliseconds value. */ public void setMilliseconds(int milliseconds) { this.milliseconds = milliseconds; } /** * Set minute field. * * @param minutes minute value. */ @Override public void setMinutes(int minutes) { this.minutes = minutes; } /** * Set month field. * * @param month month value. */ @Override public void setMonth(int month) { this.month = month; } /** * Set seconds field. * * @param seconds second value. */ @Override public void setSeconds(int seconds) { this.seconds = seconds; } /** * Set timezone offset, in minutes. * * @param tzOffset timezone offset. */ public void setTzOffset(int tzOffset) { this.tzOffset = tzOffset; } /** * Set year field. * * @param value year value. */ @Override public void setYear(int value) { this.year = value; } }