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org.apache.lucene.document
public class: DateTools [javadoc | source]

java.lang.Object
   org.apache.lucene.document.DateTools

Provides support for converting dates to strings and vice-versa. The strings are structured so that lexicographic sorting orders them by date, which makes them suitable for use as field values and search terms.

This class also helps you to limit the resolution of your dates. Do not save dates with a finer resolution than you really need, as then RangeQuery and PrefixQuery will require more memory and become slower.

Compared to DateField the strings generated by the methods in this class take slightly more space, unless your selected resolution is set to Resolution.DAY or lower.

Nested Class Summary:
public static class	DateTools.Resolution	Specifies the time granularity.

Method from org.apache.lucene.document.DateTools Summary:
dateToString,   round,   round,   stringToDate,   stringToTime,   timeToString

Methods from java.lang.Object:
equals,   getClass,   hashCode,   notify,   notifyAll,   toString,   wait,   wait,   wait

Method from org.apache.lucene.document.DateTools Detail:
public static String dateToString(Date date, DateTools.Resolution resolution) { return timeToString(date.getTime(), resolution); } Converts a Date to a string suitable for indexing.
public static Date round(Date date, DateTools.Resolution resolution) { return new Date(round(date.getTime(), resolution)); } Limit a date's resolution. For example, the date 2004-09-21 13:50:11 will be changed to 2004-09-01 00:00:00 when using Resolution.MONTH.
public static long round(long time, DateTools.Resolution resolution) { Calendar cal = Calendar.getInstance(GMT); // protected in JDK's prior to 1.4 //cal.setTimeInMillis(time); cal.setTime(new Date(time)); if (resolution == Resolution.YEAR) { cal.set(Calendar.MONTH, 0); cal.set(Calendar.DAY_OF_MONTH, 1); cal.set(Calendar.HOUR_OF_DAY, 0); cal.set(Calendar.MINUTE, 0); cal.set(Calendar.SECOND, 0); cal.set(Calendar.MILLISECOND, 0); } else if (resolution == Resolution.MONTH) { cal.set(Calendar.DAY_OF_MONTH, 1); cal.set(Calendar.HOUR_OF_DAY, 0); cal.set(Calendar.MINUTE, 0); cal.set(Calendar.SECOND, 0); cal.set(Calendar.MILLISECOND, 0); } else if (resolution == Resolution.DAY) { cal.set(Calendar.HOUR_OF_DAY, 0); cal.set(Calendar.MINUTE, 0); cal.set(Calendar.SECOND, 0); cal.set(Calendar.MILLISECOND, 0); } else if (resolution == Resolution.HOUR) { cal.set(Calendar.MINUTE, 0); cal.set(Calendar.SECOND, 0); cal.set(Calendar.MILLISECOND, 0); } else if (resolution == Resolution.MINUTE) { cal.set(Calendar.SECOND, 0); cal.set(Calendar.MILLISECOND, 0); } else if (resolution == Resolution.SECOND) { cal.set(Calendar.MILLISECOND, 0); } else if (resolution == Resolution.MILLISECOND) { // don't cut off anything } else { throw new IllegalArgumentException("unknown resolution " + resolution); } return cal.getTime().getTime(); } Limit a date's resolution. For example, the date 1095767411000 (which represents 2004-09-21 13:50:11) will be changed to 1093989600000 (2004-09-01 00:00:00) when using Resolution.MONTH.
public static Date stringToDate(String dateString) throws ParseException { Date date; if (dateString.length() == 4) { synchronized (YEAR_FORMAT) { date = YEAR_FORMAT.parse(dateString); } } else if (dateString.length() == 6) { synchronized (MONTH_FORMAT) { date = MONTH_FORMAT.parse(dateString); } } else if (dateString.length() == 8) { synchronized (DAY_FORMAT) { date = DAY_FORMAT.parse(dateString); } } else if (dateString.length() == 10) { synchronized (HOUR_FORMAT) { date = HOUR_FORMAT.parse(dateString); } } else if (dateString.length() == 12) { synchronized (MINUTE_FORMAT) { date = MINUTE_FORMAT.parse(dateString); } } else if (dateString.length() == 14) { synchronized (SECOND_FORMAT) { date = SECOND_FORMAT.parse(dateString); } } else if (dateString.length() == 17) { synchronized (MILLISECOND_FORMAT) { date = MILLISECOND_FORMAT.parse(dateString); } } else { throw new ParseException("Input is not valid date string: " + dateString, 0); } return date; } Converts a string produced by timeToString or dateToString back to a time, represented as a Date object.
public static long stringToTime(String dateString) throws ParseException { return stringToDate(dateString).getTime(); } Converts a string produced by timeToString or dateToString back to a time, represented as the number of milliseconds since January 1, 1970, 00:00:00 GMT.
public static String timeToString(long time, DateTools.Resolution resolution) { Calendar cal = Calendar.getInstance(GMT); //protected in JDK's prior to 1.4 //cal.setTimeInMillis(round(time, resolution)); cal.setTime(new Date(round(time, resolution))); String result; if (resolution == Resolution.YEAR) { synchronized (YEAR_FORMAT) { result = YEAR_FORMAT.format(cal.getTime()); } } else if (resolution == Resolution.MONTH) { synchronized (MONTH_FORMAT) { result = MONTH_FORMAT.format(cal.getTime()); } } else if (resolution == Resolution.DAY) { synchronized (DAY_FORMAT) { result = DAY_FORMAT.format(cal.getTime()); } } else if (resolution == Resolution.HOUR) { synchronized (HOUR_FORMAT) { result = HOUR_FORMAT.format(cal.getTime()); } } else if (resolution == Resolution.MINUTE) { synchronized (MINUTE_FORMAT) { result = MINUTE_FORMAT.format(cal.getTime()); } } else if (resolution == Resolution.SECOND) { synchronized (SECOND_FORMAT) { result = SECOND_FORMAT.format(cal.getTime()); } } else if (resolution == Resolution.MILLISECOND) { synchronized (MILLISECOND_FORMAT) { result = MILLISECOND_FORMAT.format(cal.getTime()); } } else { throw new IllegalArgumentException("unknown resolution " + resolution); } return result; } Converts a millisecond time to a string suitable for indexing.