01: package it.unimi.dsi.mg4j.index;
02:
03: import it.unimi.dsi.mg4j.search.Interval;
04: import it.unimi.dsi.mg4j.util.MutableString;
05:
06: /*
07: * MG4J: Managing Gigabytes for Java
08: *
09: * Copyright (C) 2004-2007 Sebastiano Vigna
10: *
11: * This library is free software; you can redistribute it and/or modify it
12: * under the terms of the GNU Lesser General Public License as published by the Free
13: * Software Foundation; either version 2.1 of the License, or (at your option)
14: * any later version.
15: *
16: * This library is distributed in the hope that it will be useful, but
17: * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
18: * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
19: * for more details.
20: *
21: * You should have received a copy of the GNU Lesser General Public License
22: * along with this program; if not, write to the Free Software
23: * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
24: *
25: */
26:
27: /** A map from prefixes to term intervals (and possibly viceversa).
28: *
29: * <P>Given a list of terms in lexicographic order numbered from 0, we can ask, given a prefix,
30: * which interval of terms starts with the given prefix. This information is very useful to
31: * satisfy prefix queries (e.g., <samp>monitor*</samp>) with a brute-force approach, that is,
32: * {@linkplain it.unimi.dsi.mg4j.search.OrDocumentIterator or-ing the document iterators} corresponding
33: * to each term. The interval is more useful than the actual list of terms starting with the prefix,
34: * as it allows to build directly the composed iterator.
35: *
36: * <P>Optionally, a prefix map may provide the opposite service: given an interval of terms, it
37: * may provide the maximum common prefix. This feature can be checked for by calling {@link #hasPrefixes()}.
38: *
39: * @author Sebastiano Vigna
40: * @since 0.9.2
41: * @deprecated As of MG4J 2.1, replaced by {@link it.unimi.dsi.util.PrefixMap}.
42: */
43:
44: @Deprecated
45: public interface PrefixMap {
46: /** Returns the interval of terms starting with the given prefix.
47: *
48: * @param prefix a prefix.
49: * @return the interval of terms starting with <code>prefix</code>
50: * ({@link it.unimi.dsi.mg4j.search.Intervals#EMPTY_INTERVAL} in case no term starts with <code>prefix</code>).
51: */
52:
53: public Interval getInterval(CharSequence prefix);
54:
55: /** Returns true if this prefix map supports {@linkplain #getPrefix(Interval) prefix retrieval}.
56: *
57: * @return true if this prefix map supports {@linkplain #getPrefix(Interval) prefix retrieval}.
58: */
59:
60: public boolean hasPrefixes();
61:
62: /** Returns the maximum prefix common to all terms in the given nonempty interval (optional operation).
63: *
64: * @param interval an interval.
65: * @return the maximum prefix common to all terms in the given nonempty interval.
66: */
67:
68: public CharSequence getPrefix(Interval interval);
69:
70: /** Writes in the given mutable string the maximum prefix common to all terms in the given nonempty interval (optional operation).
71: *
72: * @param interval an interval.
73: * @param prefix a mutable string that will be filled with the maximum prefix common to all terms in the given nonempty interval.
74: * @return <code>prefix</code>.
75: */
76:
77: public MutableString getPrefix(Interval interval,
78: MutableString prefix);
79:
80: /** Returns the number of terms in this prefix map.
81: * @return the number of terms in this prefix map.
82: */
83: public int size();
84: }
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