Java tutorial
/* The contents of this file are subject to the license and copyright terms * detailed in the license directory at the root of the source tree (also * available online at http://fedora-commons.org/license/). */ package org.fcrepo.server.utilities; import java.text.ParseException; import java.util.Date; import org.joda.time.DateTime; import org.joda.time.DateTimeZone; import org.joda.time.format.DateTimeFormat; import org.joda.time.format.DateTimeFormatter; /** * A collection of utility methods for performing frequently required tasks. * * @author Ross Wayland * @author Frank Asseg */ public abstract class DateUtility { // private static final Date ONE_BCE = new Date(-62198755200000L); private static final Date ONE_CE = new Date(-62135596800000L); private static final DateTimeFormatter FORMATTER_MILLISECONDS_T_Z = DateTimeFormat .forPattern("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'"); private static final DateTimeFormatter FORMATTER_MILLISECONDS_T = DateTimeFormat .forPattern("yyyy-MM-dd'T'HH:mm:ss.SSS"); private static final DateTimeFormatter FORMATTER_SECONDS_T_Z = DateTimeFormat .forPattern("yyyy-MM-dd'T'HH:mm:ss'Z'"); private static final DateTimeFormatter FORMATTER_SECONDS_T = DateTimeFormat.forPattern("yyyy-MM-dd'T'HH:mm:ss"); private static final DateTimeFormatter FORMATTER_SECONDS_Z = DateTimeFormat.forPattern("HH:mm:ss.SSS'Z'"); private static final DateTimeFormatter FORMATTER_DATE_Z = DateTimeFormat.forPattern("yyyy-MM-dd'Z'"); private static final DateTimeFormatter FORMATTER_DATE = DateTimeFormat.forPattern("yyyy-MM-dd"); private static final DateTimeFormatter FORMATTER_TIMEZONE = DateTimeFormat .forPattern("EEE, dd MMMM yyyyy HH:mm:ss"); static { DateTimeZone.setDefault(DateTimeZone.UTC); } /** * Converts a datetime string into and instance of java.util.Date using the * date format: yyyy-MM-ddTHH:mm:ss.SSSZ. * * @param dateTime * A datetime string * @return Corresponding instance of java.util.Date (returns null if * dateTime string argument is empty string or null) */ public static Date convertStringToDate(String dateTime) { return parseDateLoose(dateTime); } /** * Converts an instance of java.util.Date into a String using the date * format: yyyy-MM-ddTHH:mm:ss.SSSZ. * * @param date * Instance of java.util.Date. * @return ISO 8601 String representation (yyyy-MM-ddTHH:mm:ss.SSSZ) of the * Date argument or null if the Date argument is null. */ public static String convertDateToString(Date date) { return convertDateToString(date, true); } /** * Converts an instance of java.util.Date into an ISO 8601 String * representation. Uses the date format yyyy-MM-ddTHH:mm:ss.SSSZ or * yyyy-MM-ddTHH:mm:ssZ, depending on whether millisecond precision is * desired. * * @param date * Instance of java.util.Date. * @param millis * Whether or not the return value should include milliseconds. * @return ISO 8601 String representation of the Date argument or null if * the Date argument is null. */ public static String convertDateToString(Date date, boolean millis) { if (date == null) { return null; } else { DateTimeFormatter df; if (millis) { // df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'"); df = FORMATTER_MILLISECONDS_T_Z; } else { // df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'"); df = FORMATTER_SECONDS_T_Z; } return df.print(date.getTime()); } } /** * Converts an instance of <code>Date</code> into the canonical lexical * representation of an XSD dateTime with the following exceptions: - Dates * before 1 CE (i.e. 1 AD) are handled according to ISO 8601:2000 Second * Edition: "0000" is the lexical representation of 1 BCE "-0001" is the * lexical representation of 2 BCE * * @param date * Instance of java.util.Date. * @return the lexical form of the XSD dateTime value, e.g. * "2006-11-13T09:40:55.001Z". * @see <a * href="http://www.w3.org/TR/xmlschema-2/#date-canonical-representation">3.2.7.2 * Canonical representation</a> */ public static String convertDateToXSDString(Date date) { if (date == null) { return null; } String dateTime = convertDateToString(date, true); if (date.before(ONE_CE)) { // fix the format for lexical representation of the year // e.g. 1 BCE: 0000-01.01 (1BCE is year 0) int pos = dateTime.indexOf('-', 1); int year = Integer.parseInt(dateTime.substring(0, pos)); if (year == -1) { dateTime = "0000" + dateTime.substring(pos); } else if (year < 0) { year += 1; String prefix = ""; if (year > -10) { prefix = "000"; } else if (year > -100) { prefix = "00"; } else if (year > -1000) { prefix = "0"; } dateTime = "-" + prefix + Math.abs(year) + dateTime.substring(pos); } } // fix the format for the lexical representation of the milliseconds, // no leading 0s are allowed, and if it's all zeros it has to be // removed. int posDot = dateTime.indexOf('.'); int posZ = dateTime.indexOf('Z'); int millis = Integer.parseInt(dateTime.substring(posDot + 1, posZ)); String milliString; if (millis == 0) { milliString = ""; } else if (millis < 10) { milliString = ".00" + millis; } else if (millis < 100) { milliString = ".0" + millis; } else { milliString = "." + millis; } while (milliString.length() > 0 && milliString.charAt(milliString.length() - 1) == '0') { milliString = milliString.substring(0, milliString.length() - 1); } dateTime = dateTime.substring(0, posDot) + milliString + "Z"; return dateTime; } /** * Converts an instance of java.util.Date into a String using the date * format: yyyy-MM-ddZ. * * @param date * Instance of java.util.Date. * @return Corresponding date string (returns null if Date argument is * null). */ public static String convertDateToDateString(Date date) { if (date == null) { return null; } else { // DateFormat df = new SimpleDateFormat("yyyy-MM-dd'Z'"); DateTimeFormatter df = FORMATTER_DATE_Z; return df.print(date.getTime()); } } /** * Converts an instance of java.util.Date into a String using the date * format: HH:mm:ss.SSSZ. * * @param date * Instance of java.util.Date. * @return Corresponding time string (returns null if Date argument is * null). */ public static String convertDateToTimeString(Date date) { if (date == null) { return null; } else { // DateFormat df = new SimpleDateFormat("HH:mm:ss.SSS'Z'"); DateTimeFormatter df = FORMATTER_SECONDS_Z; return df.print(date.getTime()); } } /** * Convenience method for {@link #parseDateStrict(String)} which does not * throw an exception on error, but merely returns null. * * @param dateString * the date string to parse * @return Date the date, if parse was successful; null otherwise */ public static Date parseDateLoose(String dateString) { try { return parseDateStrict(dateString); } catch (ParseException e) { return null; } } /** * Convenience method for {@link #parseDateStrict(String)} with the * following difference: null or empty input returns null. Any other parse * errors are wrapped as an IllegalArgumentException. * * @param dateString * the date string to parse * @return a Date representation of the dateString or null * @throws IllegalArgumentException * if dateString is unable to be parsed. */ public static Date parseDateOrNull(String dateString) throws IllegalArgumentException { if (dateString == null) { return null; } else if (dateString.isEmpty()) { return null; } try { return parseDateStrict(dateString); } catch (ParseException e) { throw new IllegalArgumentException(e.getMessage(), e); } } /** * Attempt to parse the given string of form: yyyy-MM-dd[THH:mm:ss[.SSS][Z]] * as a Date. * * @param dateString * the date string to parse * @return a Date representation of the dateString * @throws ParseException * if dateString is null, empty or is otherwise unable to be * parsed. */ public static Date parseDateStrict(String dateString) throws ParseException { try { if (dateString == null) { throw new ParseException("Argument cannot be null.", 0); } final int last = dateString.length() - 1; if (last == -1) { throw new ParseException("Argument cannot be empty.", 0); } else if (dateString.charAt(last) == '.') { throw new ParseException("dateString ends with invalid character.", last); } // SimpleDateFormat formatter = new SimpleDateFormat(); // formatter.setTimeZone(TimeZone.getTimeZone("UTC")); final int length = (dateString.charAt(0) != '-') ? last + 1 : last; DateTimeFormatter formatter = FORMATTER_MILLISECONDS_T_Z; if (dateString.charAt(last) == 'Z') { if (length == 11) { // formatter.applyPattern("yyyy-MM-dd'Z'"); formatter = FORMATTER_DATE_Z; } else if (length == 20) { // formatter.applyPattern("yyyy-MM-dd'T'HH:mm:ss'Z'"); formatter = FORMATTER_SECONDS_T_Z; } else if (length > 21 && length < 24) { // right-pad the milliseconds with 0s up to three places int endIndex = last - 1; int dotIndex = dateString.lastIndexOf('.'); int padding = 3 - (endIndex - dotIndex); if (padding > 0) { StringBuilder sb = new StringBuilder(24); sb.append(dateString.subSequence(0, last)); switch (padding) { case 3: sb.append('0'); case 2: sb.append('0'); case 1: sb.append('0'); } sb.append('Z'); dateString = sb.toString(); } // formatter.applyPattern("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'"); formatter = FORMATTER_MILLISECONDS_T_Z; } else if (length == 24) { // formatter.applyPattern("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'"); formatter = FORMATTER_MILLISECONDS_T_Z; } } else { if (length == 10) { // formatter.applyPattern("yyyy-MM-dd"); formatter = FORMATTER_DATE; } else if (length == 19) { // formatter.applyPattern("yyyy-MM-dd'T'HH:mm:ss"); formatter = FORMATTER_SECONDS_T; } else if (length > 20 && length < 23) { // right-pad millis with 0s int endIndex = dateString.length() - 1; int dotIndex = dateString.lastIndexOf('.'); int padding = 3 - (endIndex - dotIndex); if (padding > 0) { StringBuilder sb = new StringBuilder(23); sb.append(dateString); switch (padding) { case 3: sb.append('0'); case 2: sb.append('0'); case 1: sb.append('0'); } dateString = sb.toString(); } // formatter.applyPattern("yyyy-MM-dd'T'HH:mm:ss.SSS"); formatter = FORMATTER_MILLISECONDS_T; } else if (length == 23) { // formatter.applyPattern("yyyy-MM-dd'T'HH:mm:ss.SSS"); formatter = FORMATTER_MILLISECONDS_T; } else if (dateString.endsWith("GMT") || dateString.endsWith("UTC")) { // formatter.applyPattern("EEE, dd MMMM yyyyy HH:mm:ss z"); // this has to be done by hand since Joda time can't parse // the timezone // see // http://joda-time.sourceforge.net/apidocs/org/joda/time/format/DateTimeFormat.html dateString = dateString.substring(0, last - 3); formatter = FORMATTER_TIMEZONE; } } DateTimeZone.setDefault(DateTimeZone.UTC); DateTime dt = formatter.parseDateTime(dateString); return dt.toDate(); } catch (IllegalArgumentException e) { throw new ParseException(e.getLocalizedMessage(), 0); } } public static String formatMillisTZ(Date date) { return FORMATTER_MILLISECONDS_T_Z.print(date.getTime()); } }