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16 package org.outerj.daisy.query.model;
17
18 import org.outerj.daisy.query.QueryContext;
19 import org.outerj.daisy.repository.query.QueryException;
20 import org.outerj.daisy.repository.query.EvaluationContext;
21 import org.outerj.daisy.repository.Document;
22 import org.outerj.daisy.repository.Version;
23
24 import java.util.regex.Pattern  ;
25 import java.util.regex.Matcher ;
26 import java.sql.PreparedStatement ;
27 import java.sql.SQLException ;
28
29 public class Like extends AbstractPredicateExpr {
30 private final ValueExpr valueExpr;
31 private final Literal literal;
32 private final boolean not;
33 private Pattern likePattern;
34
35 public Like(boolean not, ValueExpr valueExpr, Literal literal) {
36 this.valueExpr = valueExpr;
37 this.literal = literal;
38 this.not = not;
39 }
40
41 public void prepare(QueryContext context) throws QueryException {
42 valueExpr.prepare(context);
43 if (valueExpr.isSymbolicIdentifier())
44 throw new QueryException("A symbolic identifier cannot be used with LIKE");
45
46 if (valueExpr.getValueType() != QValueType.STRING && valueExpr.getValueType() != QValueType.UNDEFINED) {
47 throw new QueryException("LIKE can only be used for strings.");
48 }
49 }
50
51 public boolean evaluate(Document document, Version version, EvaluationContext evaluationContext) throws QueryException {
52 Object value = valueExpr.evaluate(QValueType.STRING, document, version, evaluationContext);
53 if (value instanceof Object []) {
54 Object [] values = (Object [])value;
56 for (int i = 0; i < values.length; i++) {
57 if (evaluate(values[i]))
58 return true;
59 }
60 return false;
61 } else {
62 return evaluate(value);
63 }
64 }
65
66 private boolean evaluate(Object value) throws QueryException {
67 compileLikePattern();
68 Matcher matcher = likePattern.matcher((String )value);
69 boolean matches = matcher.matches();
70 return not? !matches :matches;
71 }
72
73 public Tristate appliesTo(Document document) throws QueryException {
74 if (valueExpr.canTestAppliesTo()) {
75 boolean result = evaluate(valueExpr.evaluate(QValueType.STRING, document, null, new EvaluationContext()));
76 return result ? Tristate.YES : Tristate.NO;
77 } else {
78 return Tristate.MAYBE;
79 }
80 }
81
82
86 private void compileLikePattern() throws QueryException {
87 if (likePattern != null)
88 return;
89
90 String likeExpr = (String )literal.evaluate(QValueType.STRING);
91 StringBuffer pattern = new StringBuffer ((likeExpr.length() * 4) + 10);
92
93 boolean inEscape = false;
94 for (int i = 0; i < likeExpr.length(); i++) {
95 char c = likeExpr.charAt(i);
96 switch (c) {
97 case '%':
98 if (inEscape) {
99 inEscape = false;
100 pattern.append('%');
101 } else {
102 pattern.append(".*");
103 }
104 break;
105 case '_':
106 if (inEscape) {
107 inEscape = false;
108 pattern.append('_');
109 } else {
110 pattern.append('.');
111 }
112 break;
113 case '\\':
114 inEscape = true;
116 break;
117 default:
118 char ch1 = Character.forDigit((c >> 4) & 0xF, 16);
119 char ch2 = Character.forDigit(c & 0xF, 16);
120 pattern.append('\\').append('u').append('0').append('0').append(ch1).append(ch2);
121 break;
122 }
123 }
124 likePattern = Pattern.compile(pattern.toString());
125 }
126
127 public AclConditionViolation isAclAllowed() {
128 return valueExpr.isAclAllowed();
129 }
130
131 public void generateSql(StringBuffer sql, SqlGenerationContext context) throws QueryException {
132 sql.append(" (");
133 String preCond = valueExpr.getSqlPreConditions(context);
134 if (preCond != null)
135 sql.append(preCond).append(" AND ");
136 valueExpr.generateSqlValueExpr(sql, context);
137 if (not)
138 sql.append(" NOT LIKE ");
139 else
140 sql.append(" LIKE ");
141 sql.append(" ?) ");
142 }
143
144 public int bindSql(PreparedStatement stmt, int bindPos, EvaluationContext evaluationContext) throws SQLException , QueryException {
145 bindPos = valueExpr.bindPreConditions(stmt, bindPos);
146 bindPos = valueExpr.bindValueExpr(stmt, bindPos, QValueType.STRING, evaluationContext);
147 bindPos = literal.bindValueExpr(stmt, bindPos, QValueType.STRING, evaluationContext);
148 return bindPos;
149 }
150 }
151 |
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