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1 package com.quadcap.sql.types;
2
3
40
41 import java.io.Externalizable  ;
42 import java.io.IOException ;
43 import java.io.ObjectInput ;
44 import java.io.ObjectOutput ;
45
46 import antlr.RecognitionException;
47
48 import com.quadcap.util.Debug;
49
50
55 public class ValuePattern extends Value implements Externalizable {
56 String pattern;
57 char escape = 0;
58 public static final String defaultEscape = "\\";
59
60 public ValuePattern() {}
61
62 public ValuePattern(String pattern, String esc) throws ValueException {
63 this.pattern = pattern;
64 if (esc != null) {
65 if (esc.length() != 1) {
66 throw new ValueException(
67 "Pattern escape must be a single character");
68 }
69 escape = esc.charAt(0);
70 }
71 }
72
73 public Value binop(int op, Value l) throws ValueException {
74 return l.binop(op, this);
75 }
76
77 public static final Value binop(int op, ValueString l, ValuePattern r)
78 throws ValueException
79 {
80 if (op != Op.LIKE) {
81 throw new ValueException("Not implemented: " +
82 Op.toString(op));
83 }
84 String ls = l.stringValue();
85 String rs = r.pattern;
86 return new ValueBoolean(pMatch(ls, 0, rs, 0, r.escape));
87 }
88
89 static final char getChar(final String s, int i) {
90 if (isCaseSensitive) {
91 return s.charAt(i);
92 } else {
93 return Character.toLowerCase(s.charAt(i));
94 }
95 }
96
97
100 static boolean pMatch(String va, int a, String vb, int b, char escape)
101 throws ValueException
102 {
103 while (b < vb.length()) {
104 char p = getChar(vb, b++);
105 switch (p) {
106 case '%':
107 if (b >= vb.length()) return true;
108 while (a < va.length()) {
109 if (pMatch(va, a++, vb, b, escape)) return true;
110 }
111 return false;
112 case '_':
113 if (a++ >= va.length()) return false;
114 break;
115 default:
116 if (a >= va.length()) return false;
117 if (p == escape) {
118 if (b >= vb.length()) {
119 throw new ValueException("Invalid escape sequence");
120 }
121 p = getChar(vb, b++);
122 if (p != '_' && p != '%' && p != escape) {
123 throw new ValueException("Invalid escape sequence");
124 }
125 }
126 if (getChar(va, a++) != p) {
127 return false;
128 }
129 }
130 }
131 return a >= va.length();
132 }
133
134 public void readExternal(ObjectInput in)
135 throws IOException , ClassNotFoundException
136 {
137 pattern = (String )in.readObject();
138 escape = in.readChar();
139 }
140
141 public void writeExternal(ObjectOutput out) throws IOException {
142 out.writeObject(pattern);
143 out.writeChar(escape);
144 }
145
146 public String toString() {
147 StringBuffer sb = new StringBuffer ("'");
148 sb.append(pattern);
149 sb.append('\'');
150 if (escape != 0) {
151 sb.append(" ESCAPE '");
152 sb.append(escape);
153 sb.append('\'');
154 }
155 return sb.toString();
156 }
157
158 public Object asJavaObject() {
159 return pattern;
160 }
161
162 public void fromJavaObject(Object obj) throws ValueException {
163 throw new ValueException("bad type: " + obj);
164 }
165
166 public Type getType() {
167 return TypeVarChar.typeVarChar;
168 }
169
170 public void serializeKey(KeyStream out) throws IOException {
171 throw new IOException ("Can't use 'pattern' as key");
172 }
173 }
174 |
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