Java tutorial
/* =========================================================== * JFreeChart : a free chart library for the Java(tm) platform * =========================================================== * * (C) Copyright 2000-2013, by Object Refinery Limited and Contributors. * * Project Info: http://www.jfree.org/jfreechart/index.html * * This library is free software; you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License as published by * the Free Software Foundation; either version 2.1 of the License, or * (at your option) any later version. * * This library is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public * License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, * USA. * * [Oracle and Java are registered trademarks of Oracle and/or its affiliates. * Other names may be trademarks of their respective owners.] * * --------- * Week.java * --------- * (C) Copyright 2001-2013, by Object Refinery Limited and Contributors. * * Original Author: David Gilbert (for Object Refinery Limited); * Contributor(s): Aimin Han; * * Changes * ------- * 11-Oct-2001 : Version 1 (DG); * 18-Dec-2001 : Changed order of parameters in constructor (DG); * 19-Dec-2001 : Added a new constructor as suggested by Paul English (DG); * 29-Jan-2002 : Worked on the parseWeek() method (DG); * 13-Feb-2002 : Fixed bug in Week(Date) constructor (DG); * 26-Feb-2002 : Changed getStart(), getMiddle() and getEnd() methods to * evaluate with reference to a particular time zone (DG); * 05-Apr-2002 : Reinstated this class to the JCommon library (DG); * 24-Jun-2002 : Removed unnecessary main method (DG); * 10-Sep-2002 : Added getSerialIndex() method (DG); * 06-Oct-2002 : Fixed errors reported by Checkstyle (DG); * 18-Oct-2002 : Changed to observe 52 or 53 weeks per year, consistent with * GregorianCalendar. Thanks to Aimin Han for the code (DG); * 02-Jan-2003 : Removed debug code (DG); * 13-Mar-2003 : Moved to com.jrefinery.data.time package, and implemented * Serializable (DG); * 21-Oct-2003 : Added hashCode() method (DG); * 24-May-2004 : Modified getFirstMillisecond() and getLastMillisecond() to * take account of firstDayOfWeek setting in Java's Calendar * class (DG); * 30-Sep-2004 : Replaced getTime().getTime() with getTimeInMillis() (DG); * 04-Nov-2004 : Reverted change of 30-Sep-2004, because it won't work for * JDK 1.3 (DG); * ------------- JFREECHART 1.0.x --------------------------------------------- * 06-Mar-2006 : Fix for bug 1448828, incorrect calculation of week and year * for the first few days of some years (DG); * 05-Oct-2006 : Updated API docs (DG); * 06-Oct-2006 : Refactored to cache first and last millisecond values (DG); * 09-Jan-2007 : Fixed bug in next() (DG); * 28-Aug-2007 : Added new constructor to avoid problem in creating new * instances (DG); * 19-Dec-2007 : Fixed bug in deprecated constructor (DG); * 16-Sep-2008 : Deprecated DEFAULT_TIME_ZONE (DG); * 05-Jul-2012 : Replaced getTime().getTime() with getTimeInMillis() (DG); * 03-Jul-2013 : Use ParamChecks (DG); * */ package org.jfree.data.time; import java.io.Serializable; import java.util.Calendar; import java.util.Date; import java.util.Locale; import java.util.TimeZone; import org.jfree.chart.util.ParamChecks; /** * A calendar week. All years are considered to have 53 weeks, numbered from 1 * to 53, although in many cases the 53rd week is empty. Most of the time, the * 1st week of the year *begins* in the previous calendar year, but it always * finishes in the current year (this behaviour matches the workings of the * <code>GregorianCalendar</code> class). * <P> * This class is immutable, which is a requirement for all * {@link RegularTimePeriod} subclasses. */ public class Week extends RegularTimePeriod implements Serializable { /** For serialization. */ private static final long serialVersionUID = 1856387786939865061L; /** Constant for the first week in the year. */ public static final int FIRST_WEEK_IN_YEAR = 1; /** Constant for the last week in the year. */ public static final int LAST_WEEK_IN_YEAR = 53; /** The year in which the week falls. */ private short year; /** The week (1-53). */ private byte week; /** The first millisecond. */ private long firstMillisecond; /** The last millisecond. */ private long lastMillisecond; /** * Creates a new time period for the week in which the current system * date/time falls. */ public Week() { this(new Date()); } /** * Creates a time period representing the week in the specified year. * * @param week the week (1 to 53). * @param year the year (1900 to 9999). */ public Week(int week, int year) { if ((week < FIRST_WEEK_IN_YEAR) && (week > LAST_WEEK_IN_YEAR)) { throw new IllegalArgumentException("The 'week' argument must be in the range 1 - 53."); } this.week = (byte) week; this.year = (short) year; peg(Calendar.getInstance()); } /** * Creates a time period representing the week in the specified year. * * @param week the week (1 to 53). * @param year the year (1900 to 9999). */ public Week(int week, Year year) { if ((week < FIRST_WEEK_IN_YEAR) && (week > LAST_WEEK_IN_YEAR)) { throw new IllegalArgumentException("The 'week' argument must be in the range 1 - 53."); } this.week = (byte) week; this.year = (short) year.getYear(); peg(Calendar.getInstance()); } /** * Creates a time period for the week in which the specified date/time * falls, using the default time zone and locale (the locale can affect the * day-of-the-week that marks the beginning of the week, as well as the * minimal number of days in the first week of the year). * * @param time the time (<code>null</code> not permitted). * * @see #Week(Date, TimeZone, Locale) */ public Week(Date time) { // defer argument checking... this(time, TimeZone.getDefault(), Locale.getDefault()); } /** * Creates a time period for the week in which the specified date/time * falls, calculated relative to the specified time zone. * * @param time the date/time (<code>null</code> not permitted). * @param zone the time zone (<code>null</code> not permitted). * * @deprecated As of 1.0.7, use {@link #Week(Date, TimeZone, Locale)}. */ public Week(Date time, TimeZone zone) { // defer argument checking... this(time, zone, Locale.getDefault()); } /** * Creates a time period for the week in which the specified date/time * falls, calculated relative to the specified time zone. * * @param time the date/time (<code>null</code> not permitted). * @param zone the time zone (<code>null</code> not permitted). * @param locale the locale (<code>null</code> not permitted). * * @since 1.0.7 */ public Week(Date time, TimeZone zone, Locale locale) { ParamChecks.nullNotPermitted(time, "time"); ParamChecks.nullNotPermitted(zone, "zone"); ParamChecks.nullNotPermitted(locale, "locale"); Calendar calendar = Calendar.getInstance(zone, locale); calendar.setTime(time); // sometimes the last few days of the year are considered to fall in // the *first* week of the following year. Refer to the Javadocs for // GregorianCalendar. int tempWeek = calendar.get(Calendar.WEEK_OF_YEAR); if (tempWeek == 1 && calendar.get(Calendar.MONTH) == Calendar.DECEMBER) { this.week = 1; this.year = (short) (calendar.get(Calendar.YEAR) + 1); } else { this.week = (byte) Math.min(tempWeek, LAST_WEEK_IN_YEAR); int yyyy = calendar.get(Calendar.YEAR); // alternatively, sometimes the first few days of the year are // considered to fall in the *last* week of the previous year... if (calendar.get(Calendar.MONTH) == Calendar.JANUARY && this.week >= 52) { yyyy--; } this.year = (short) yyyy; } peg(calendar); } /** * Returns the year in which the week falls. * * @return The year (never <code>null</code>). */ public Year getYear() { return new Year(this.year); } /** * Returns the year in which the week falls, as an integer value. * * @return The year. */ public int getYearValue() { return this.year; } /** * Returns the week. * * @return The week. */ public int getWeek() { return this.week; } /** * Returns the first millisecond of the week. This will be determined * relative to the time zone specified in the constructor, or in the * calendar instance passed in the most recent call to the * {@link #peg(Calendar)} method. * * @return The first millisecond of the week. * * @see #getLastMillisecond() */ @Override public long getFirstMillisecond() { return this.firstMillisecond; } /** * Returns the last millisecond of the week. This will be * determined relative to the time zone specified in the constructor, or * in the calendar instance passed in the most recent call to the * {@link #peg(Calendar)} method. * * @return The last millisecond of the week. * * @see #getFirstMillisecond() */ @Override public long getLastMillisecond() { return this.lastMillisecond; } /** * Recalculates the start date/time and end date/time for this time period * relative to the supplied calendar (which incorporates a time zone). * * @param calendar the calendar (<code>null</code> not permitted). * * @since 1.0.3 */ @Override public void peg(Calendar calendar) { this.firstMillisecond = getFirstMillisecond(calendar); this.lastMillisecond = getLastMillisecond(calendar); } /** * Returns the week preceding this one. This method will return * <code>null</code> for some lower limit on the range of weeks (currently * week 1, 1900). For week 1 of any year, the previous week is always week * 53, but week 53 may not contain any days (you should check for this). * * @return The preceding week (possibly <code>null</code>). */ @Override public RegularTimePeriod previous() { Week result; if (this.week != FIRST_WEEK_IN_YEAR) { result = new Week(this.week - 1, this.year); } else { // we need to work out if the previous year has 52 or 53 weeks... if (this.year > 1900) { int yy = this.year - 1; Calendar prevYearCalendar = Calendar.getInstance(); prevYearCalendar.set(yy, Calendar.DECEMBER, 31); result = new Week(prevYearCalendar.getActualMaximum(Calendar.WEEK_OF_YEAR), yy); } else { result = null; } } return result; } /** * Returns the week following this one. This method will return * <code>null</code> for some upper limit on the range of weeks (currently * week 53, 9999). For week 52 of any year, the following week is always * week 53, but week 53 may not contain any days (you should check for * this). * * @return The following week (possibly <code>null</code>). */ @Override public RegularTimePeriod next() { Week result; if (this.week < 52) { result = new Week(this.week + 1, this.year); } else { Calendar calendar = Calendar.getInstance(); calendar.set(this.year, Calendar.DECEMBER, 31); int actualMaxWeek = calendar.getActualMaximum(Calendar.WEEK_OF_YEAR); if (this.week < actualMaxWeek) { result = new Week(this.week + 1, this.year); } else { if (this.year < 9999) { result = new Week(FIRST_WEEK_IN_YEAR, this.year + 1); } else { result = null; } } } return result; } /** * Returns a serial index number for the week. * * @return The serial index number. */ @Override public long getSerialIndex() { return this.year * 53L + this.week; } /** * Returns the first millisecond of the week, evaluated using the supplied * calendar (which determines the time zone). * * @param calendar the calendar (<code>null</code> not permitted). * * @return The first millisecond of the week. * * @throws NullPointerException if <code>calendar</code> is * <code>null</code>. */ @Override public long getFirstMillisecond(Calendar calendar) { Calendar c = (Calendar) calendar.clone(); c.clear(); c.set(Calendar.YEAR, this.year); c.set(Calendar.WEEK_OF_YEAR, this.week); c.set(Calendar.DAY_OF_WEEK, c.getFirstDayOfWeek()); c.set(Calendar.HOUR, 0); c.set(Calendar.MINUTE, 0); c.set(Calendar.SECOND, 0); c.set(Calendar.MILLISECOND, 0); return c.getTimeInMillis(); } /** * Returns the last millisecond of the week, evaluated using the supplied * calendar (which determines the time zone). * * @param calendar the calendar (<code>null</code> not permitted). * * @return The last millisecond of the week. * * @throws NullPointerException if <code>calendar</code> is * <code>null</code>. */ @Override public long getLastMillisecond(Calendar calendar) { Calendar c = (Calendar) calendar.clone(); c.clear(); c.set(Calendar.YEAR, this.year); c.set(Calendar.WEEK_OF_YEAR, this.week + 1); c.set(Calendar.DAY_OF_WEEK, c.getFirstDayOfWeek()); c.set(Calendar.HOUR, 0); c.set(Calendar.MINUTE, 0); c.set(Calendar.SECOND, 0); c.set(Calendar.MILLISECOND, 0); return c.getTimeInMillis() - 1; } /** * Returns a string representing the week (e.g. "Week 9, 2002"). * * TODO: look at internationalisation. * * @return A string representing the week. */ @Override public String toString() { return "Week " + this.week + ", " + this.year; } /** * Tests the equality of this Week object to an arbitrary object. Returns * true if the target is a Week instance representing the same week as this * object. In all other cases, returns false. * * @param obj the object (<code>null</code> permitted). * * @return <code>true</code> if week and year of this and object are the * same. */ @Override public boolean equals(Object obj) { if (obj == this) { return true; } if (!(obj instanceof Week)) { return false; } Week that = (Week) obj; if (this.week != that.week) { return false; } if (this.year != that.year) { return false; } return true; } /** * Returns a hash code for this object instance. The approach described by * Joshua Bloch in "Effective Java" has been used here: * <p> * <code>http://developer.java.sun.com/developer/Books/effectivejava * /Chapter3.pdf</code> * * @return A hash code. */ @Override public int hashCode() { int result = 17; result = 37 * result + this.week; result = 37 * result + this.year; return result; } /** * Returns an integer indicating the order of this Week object relative to * the specified object: * * negative == before, zero == same, positive == after. * * @param o1 the object to compare. * * @return negative == before, zero == same, positive == after. */ @Override public int compareTo(Object o1) { int result; // CASE 1 : Comparing to another Week object // -------------------------------------------- if (o1 instanceof Week) { Week w = (Week) o1; result = this.year - w.getYear().getYear(); if (result == 0) { result = this.week - w.getWeek(); } } // CASE 2 : Comparing to another TimePeriod object // ----------------------------------------------- else if (o1 instanceof RegularTimePeriod) { // more difficult case - evaluate later... result = 0; } // CASE 3 : Comparing to a non-TimePeriod object // --------------------------------------------- else { // consider time periods to be ordered after general objects result = 1; } return result; } /** * Parses the string argument as a week. * <P> * This method is required to accept the format "YYYY-Wnn". It will also * accept "Wnn-YYYY". Anything else, at the moment, is a bonus. * * @param s string to parse. * * @return <code>null</code> if the string is not parseable, the week * otherwise. */ public static Week parseWeek(String s) { Week result = null; if (s != null) { // trim whitespace from either end of the string s = s.trim(); int i = Week.findSeparator(s); if (i != -1) { String s1 = s.substring(0, i).trim(); String s2 = s.substring(i + 1, s.length()).trim(); Year y = Week.evaluateAsYear(s1); int w; if (y != null) { w = Week.stringToWeek(s2); if (w == -1) { throw new TimePeriodFormatException("Can't evaluate the week."); } result = new Week(w, y); } else { y = Week.evaluateAsYear(s2); if (y != null) { w = Week.stringToWeek(s1); if (w == -1) { throw new TimePeriodFormatException("Can't evaluate the week."); } result = new Week(w, y); } else { throw new TimePeriodFormatException("Can't evaluate the year."); } } } else { throw new TimePeriodFormatException("Could not find separator."); } } return result; } /** * Finds the first occurrence of ' ', '-', ',' or '.' * * @param s the string to parse. * * @return <code>-1</code> if none of the characters was found, the * index of the first occurrence otherwise. */ private static int findSeparator(String s) { int result = s.indexOf('-'); if (result == -1) { result = s.indexOf(','); } if (result == -1) { result = s.indexOf(' '); } if (result == -1) { result = s.indexOf('.'); } return result; } /** * Creates a year from a string, or returns null (format exceptions * suppressed). * * @param s string to parse. * * @return <code>null</code> if the string is not parseable, the year * otherwise. */ private static Year evaluateAsYear(String s) { Year result = null; try { result = Year.parseYear(s); } catch (TimePeriodFormatException e) { // suppress } return result; } /** * Converts a string to a week. * * @param s the string to parse. * @return <code>-1</code> if the string does not contain a week number, * the number of the week otherwise. */ private static int stringToWeek(String s) { int result = -1; s = s.replace('W', ' '); s = s.trim(); try { result = Integer.parseInt(s); if ((result < 1) || (result > LAST_WEEK_IN_YEAR)) { result = -1; } } catch (NumberFormatException e) { // suppress } return result; } }