package org.apache.lucene.document;
/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.
*/
import org.apache.lucene.search.PrefixQuery;
import org.apache.lucene.search.TermRangeQuery;
import org.apache.lucene.search.NumericRangeQuery; // for javadocs
import org.apache.lucene.util.NumericUtils; // for javadocs
import java.util.Date; // for javadoc
import java.util.Calendar; // for javadoc
// do not remove in 3.0, needed for reading old indexes!
/**
* Provides support for converting dates to strings and vice-versa.
* The strings are structured so that lexicographic sorting orders by date,
* which makes them suitable for use as field values and search terms.
*
* <P>Note that this class saves dates with millisecond granularity,
* which is bad for {@link TermRangeQuery} and {@link PrefixQuery}, as those
* queries are expanded to a BooleanQuery with a potentially large number
* of terms when searching. Thus you might want to use
* {@link DateTools} instead.
*
* <P>
* Note: dates before 1970 cannot be used, and therefore cannot be
* indexed when using this class. See {@link DateTools} for an
* alternative without such a limitation.
*
* <P>
* Another approach is {@link NumericUtils}, which provides
* a sortable binary representation (prefix encoded) of numeric values, which
* date/time are.
* For indexing a {@link Date} or {@link Calendar}, just get the unix timestamp as
* <code>long</code> using {@link Date#getTime} or {@link Calendar#getTimeInMillis} and
* index this as a numeric value with {@link NumericField}
* and use {@link NumericRangeQuery} to query it.
*
* @deprecated If you build a new index, use {@link DateTools} or
* {@link NumericField} instead.
* This class is included for use with existing
* indices and will be removed in a future release (possibly Lucene 4.0).
*/
@Deprecated
public class DateField {
private DateField() {}
// make date strings long enough to last a millenium
private static int DATE_LEN = Long.toString(1000L*365*24*60*60*1000,
Character.MAX_RADIX).length();
public static String MIN_DATE_STRING() {
return timeToString(0);
}
public static String MAX_DATE_STRING() {
char[] buffer = new char[DATE_LEN];
char c = Character.forDigit(Character.MAX_RADIX-1, Character.MAX_RADIX);
for (int i = 0 ; i < DATE_LEN; i++)
buffer[i] = c;
return new String(buffer);
}
/**
* Converts a Date to a string suitable for indexing.
* @throws RuntimeException if the date specified in the
* method argument is before 1970
*/
public static String dateToString(Date date) {
return timeToString(date.getTime());
}
/**
* Converts a millisecond time to a string suitable for indexing.
* @throws RuntimeException if the time specified in the
* method argument is negative, that is, before 1970
*/
public static String timeToString(long time) {
if (time < 0)
throw new RuntimeException("time '" + time + "' is too early, must be >= 0");
String s = Long.toString(time, Character.MAX_RADIX);
if (s.length() > DATE_LEN)
throw new RuntimeException("time '" + time + "' is too late, length of string " +
"representation must be <= " + DATE_LEN);
// Pad with leading zeros
if (s.length() < DATE_LEN) {
StringBuilder sb = new StringBuilder(s);
while (sb.length() < DATE_LEN)
sb.insert(0, 0);
s = sb.toString();
}
return s;
}
/** Converts a string-encoded date into a millisecond time. */
public static long stringToTime(String s) {
return Long.parseLong(s, Character.MAX_RADIX);
}
/** Converts a string-encoded date into a Date object. */
public static Date stringToDate(String s) {
return new Date(stringToTime(s));
}
}