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package it.unimi.dsi.util;
/*
* DSI utilities
*
* Copyright (C) 2004-2009 Sebastiano Vigna
*
* 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 program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
*/
import it.unimi.dsi.fastutil.objects.Object2ObjectFunction;
/** A map from prefixes to string intervals (and possibly vice versa).
*
* Instances of this class provide the services of a {@link StringMap}, but by assuming
* the strings are lexicographically ordered, they can provide further information by
* exposing a {@linkplain #rangeMap() function from string prefixes to intervals} and a
* {@linkplain #prefixMap() function from intervals to string prefixes}.
*
*
In the first case, given a prefix, we can ask for the range of strings starting
* with that prefix, expressed as an {@link Interval}. This information is very useful to
* satisfy prefix queries (e.g., monitor*) with a brute-force approach.
*
*
Optionally, a prefix map may provide the opposite service: given an interval of terms, it
* may provide the maximum common prefix. This feature can be checked for by calling
* {@link #prefixMap()}.
*
* @author Sebastiano Vigna
* @since 0.9.2
*/
public interface PrefixMap extends StringMap {
/** Returns a function mapping prefixes to ranges of strings.
*
* @return a function mapping prefixes to ranges of strings.
*/
public Object2ObjectFunction rangeMap();
/** Returns a function mapping ranges of strings to common prefixes (optional operation).
*
* @return a function mapping ranges of strings to common prefixes, or null if this
* map does not support prefixes.
*/
public Object2ObjectFunction prefixMap();
}