1
package org.apache.lucene.search;
4
* Licensed to the Apache Software Foundation (ASF) under one or more
5
* contributor license agreements. See the NOTICE file distributed with
6
* this work for additional information regarding copyright ownership.
7
* The ASF licenses this file to You under the Apache License, Version 2.0
8
* (the "License"); you may not use this file except in compliance with
9
* the License. You may obtain a copy of the License at
11
* http://www.apache.org/licenses/LICENSE-2.0
13
* Unless required by applicable law or agreed to in writing, software
14
* distributed under the License is distributed on an "AS IS" BASIS,
15
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16
* See the License for the specific language governing permissions and
17
* limitations under the License.
20
import java.io.IOException;
22
import org.apache.lucene.index.IndexReader;
23
import org.apache.lucene.index.Term;
26
* Subclass of FilteredTermEnum for enumerating all terms that match the
27
* specified wildcard filter term.
29
* Term enumerations are always ordered by Term.compareTo(). Each term in
30
* the enumeration is greater than all that precede it.
32
public class WildcardTermEnum extends FilteredTermEnum {
33
final Term searchTerm;
38
boolean endEnum = false;
41
* Creates a new <code>WildcardTermEnum</code>.
43
* After calling the constructor the enumeration is already pointing to the first
44
* valid term if such a term exists.
46
public WildcardTermEnum(IndexReader reader, Term term) throws IOException {
49
field = searchTerm.field();
50
final String searchTermText = searchTerm.text();
52
final int sidx = searchTermText.indexOf(WILDCARD_STRING);
53
final int cidx = searchTermText.indexOf(WILDCARD_CHAR);
59
idx = Math.min(idx, cidx);
61
pre = idx != -1?searchTerm.text().substring(0,idx): "";
63
preLen = pre.length();
64
text = searchTermText.substring(preLen);
65
setEnum(reader.terms(new Term(searchTerm.field(), pre)));
69
protected final boolean termCompare(Term term) {
70
if (field == term.field()) {
71
String searchText = term.text();
72
if (searchText.startsWith(pre)) {
73
return wildcardEquals(text, 0, searchText, preLen);
81
public float difference() {
86
public final boolean endEnum() {
90
/********************************************
91
* String equality with support for wildcards
92
********************************************/
94
public static final char WILDCARD_STRING = '*';
95
public static final char WILDCARD_CHAR = '?';
98
* Determines if a word matches a wildcard pattern.
99
* <small>Work released by Granta Design Ltd after originally being done on
100
* company time.</small>
102
public static final boolean wildcardEquals(String pattern, int patternIdx,
103
String string, int stringIdx)
107
for (int s = stringIdx; ; ++p, ++s)
109
// End of string yet?
110
boolean sEnd = (s >= string.length());
111
// End of pattern yet?
112
boolean pEnd = (p >= pattern.length());
114
// If we're looking at the end of the string...
117
// Assume the only thing left on the pattern is/are wildcards
118
boolean justWildcardsLeft = true;
120
// Current wildcard position
121
int wildcardSearchPos = p;
122
// While we haven't found the end of the pattern,
123
// and haven't encountered any non-wildcard characters
124
while (wildcardSearchPos < pattern.length() && justWildcardsLeft)
126
// Check the character at the current position
127
char wildchar = pattern.charAt(wildcardSearchPos);
129
// If it's not a wildcard character, then there is more
130
// pattern information after this/these wildcards.
131
if (wildchar != WILDCARD_CHAR && wildchar != WILDCARD_STRING)
133
justWildcardsLeft = false;
137
// to prevent "cat" matches "ca??"
138
if (wildchar == WILDCARD_CHAR) {
142
// Look at the next character
147
// This was a prefix wildcard search, and we've matched, so
149
if (justWildcardsLeft)
155
// If we've gone past the end of the string, or the pattern,
162
// Match a single character, so continue.
163
if (pattern.charAt(p) == WILDCARD_CHAR)
169
if (pattern.charAt(p) == WILDCARD_STRING)
171
// Look at the character beyond the '*' characters.
172
while (p < pattern.length() && pattern.charAt(p) == WILDCARD_STRING)
174
// Examine the string, starting at the last character.
175
for (int i = string.length(); i >= s; --i)
177
if (wildcardEquals(pattern, p, string, i))
184
if (pattern.charAt(p) != string.charAt(s))