1 karl 1.9 //%2005////////////////////////////////////////////////////////////////////////
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2 mike 1.2 //
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3 karl 1.7 // Copyright (c) 2000, 2001, 2002 BMC Software; Hewlett-Packard Development
4 // Company, L.P.; IBM Corp.; The Open Group; Tivoli Systems.
5 // Copyright (c) 2003 BMC Software; Hewlett-Packard Development Company, L.P.;
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6 karl 1.6 // IBM Corp.; EMC Corporation, The Open Group.
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7 karl 1.7 // Copyright (c) 2004 BMC Software; Hewlett-Packard Development Company, L.P.;
8 // IBM Corp.; EMC Corporation; VERITAS Software Corporation; The Open Group.
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9 karl 1.9 // Copyright (c) 2005 Hewlett-Packard Development Company, L.P.; IBM Corp.;
10 // EMC Corporation; VERITAS Software Corporation; The Open Group.
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11 mike 1.2 //
12 // Permission is hereby granted, free of charge, to any person obtaining a copy
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13 kumpf 1.4 // of this software and associated documentation files (the "Software"), to
14 // deal in the Software without restriction, including without limitation the
15 // rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
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16 mike 1.2 // sell copies of the Software, and to permit persons to whom the Software is
17 // furnished to do so, subject to the following conditions:
18 //
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19 kumpf 1.4 // THE ABOVE COPYRIGHT NOTICE AND THIS PERMISSION NOTICE SHALL BE INCLUDED IN
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20 mike 1.2 // ALL COPIES OR SUBSTANTIAL PORTIONS OF THE SOFTWARE. THE SOFTWARE IS PROVIDED
21 // "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT
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22 kumpf 1.4 // LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
23 // PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
24 // HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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25 mike 1.2 // ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
26 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
27 //
28 //==============================================================================
29 //
30 // Author: Mike Brasher (mbrasher@bmc.com)
31 //
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32 david.dillard 1.8 // Modified By: David Dillard, VERITAS Software Corp.
33 // (david.dillard@veritas.com)
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34 mike 1.2 //
35 //%/////////////////////////////////////////////////////////////////////////////
36
37 #ifndef Pegasus_WQLParser_h
38 #define Pegasus_WQLParser_h
39
40 #include <Pegasus/Common/Config.h>
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41 kumpf 1.5 #include <Pegasus/Common/ArrayInternal.h>
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42 mike 1.2 #include <Pegasus/WQL/Linkage.h>
43 #include <Pegasus/WQL/WQLSelectStatement.h>
44
45 PEGASUS_NAMESPACE_BEGIN
46
47 /** This class is the main interface to the WQL parser used for parsing WQL1
48 compliant SQL statements.
49
50 Here's an example which parses a SELECT statement:
51
52 <pre>
53 const char TEXT[] = "SELECT X,Y FROM MyClass WHERE X > 10 AND Y < 3";
54
55 // Note that this array must be null-terminated (sizeof(TEXT) includes
56 // the null-terminator in the count).
57
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58 david.dillard 1.8 Array<char> text(TEXT, sizeof(TEXT));
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59 mike 1.2
60 WQLSelectStatement selectStatement;
61
62 WQLParser parser;
63
64 try
65 {
66 parser.parse(text, selectStatement);
67 }
68 catch (ParseError&)
69 {
70 ...
71 }
72 catch (MissingNullTerminator&)
73 {
74 ...
75 }
76 </pre>
77
78 Note that the text must be NULL terminated or else the MissingNullTerminator
79 exception is thrown.
80 mike 1.2
81 The text is read and the result is left in the selectStatement output
82 argument.
83
84 At this point you might wish to peek at the contents of the selectStatement.
85 This may be done by calling WQLSelectStatement::print() like this:
86
87 <pre>
88 WQLSelectStatement selectStatement;
89 ...
90 selectStatement.print();
91 </pre>
92
93 For the above query text, the following is printed:
94
95 <pre>
96 WQLSelectStatement
97 {
98 _className: "MyClass"
99
100 _propertyNames[0]: "X"
101 mike 1.2 _propertyNames[1]: "Y"
102
103 _operations[0]: "WQL_GT"
104 _operations[1]: "WQL_LT"
105 _operations[2]: "WQL_AND"
106
107 _operands[0]: "PROPERTY_NAME: X"
108 _operands[1]: "INTEGER_VALUE: 10"
109 _operands[2]: "PROPERTY_NAME: Y"
110 _operands[3]: "INTEGER_VALUE: 3"
111 }
112 </pre>
113
114 The WQLSelectStatement::evaluateWhereClause() method may be called to
115 determine whether a particular instance (whose properties are made
116 available to he evaluateWhereClause() by a user implementation of the
117 WQLPropertySource class). This method returns true, if the where clause
118 matches this instance. Here is an example:
119
120 <pre>
121 WQLSelectStatement selectStatement;
122 mike 1.2 ...
123 WQLPropertySource* propertySource = new MyPropertySource(...);
124
125 if (selectStatement.evaluateWhereClause(propertySource))
126 {
127 // It's a match!
128 }
129 </pre>
130
131 The evaluateWhereClause() method calls propertySource->getValue() to
132 obtain values for each of the properties referred to in where clause (X
133 and Y in the above query example).
134
135 The implementer of the WQLPropertySource interface must provide the
136 implementation of getValue() to produce values for the target data
137 types. The WQL library makes no assumptions about the nature of the
138 target data representation. This was done so that this libary could be
139 adapted to multiple data representations.
140
141 For use with Pegasus CIMInstance objects, a CIMInstancePropertySource
142 class could be developed whose getValue() method fetches values from
143 mike 1.2 a CIMInstance. Here is an example of how it might be used.
144
145 <pre>
146 CIMInstancePropertySource* propertySource
147 = new CIMInstancePropertySource(...);
148
149 CIMInstance instance;
150
151 while (instance = GetNextInstance(...))
152 {
153 propertySource->setInstance(currentInstance);
154
155 if (selectStatement.evaluateWhereClause(propertySource))
156 {
157 // It's a match!
158 }
159 }
160 </pre>
161
162 Of course the numeration of instances is left to the user of WQL.
163 */
164 mike 1.2 class PEGASUS_WQL_LINKAGE WQLParser
165 {
166 public:
167
168 /** Parse the SELECT statement given by the text parameter and initialize
169 the statement parameter accordingly.
170
171 Please note that this method is not thread safe. It must be guarded
172 with mutexes by the caller.
173
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174 mike 1.3 @param text null-terminated C-string which points to SQL statement.
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175 mike 1.2 @param statement object which holds the compiled version of the SELECT
176 statement upon return.
177 @exception ParseError if text is not a valid SELECT statement.
178 @exception MissingNullTerminator if text argument is not
179 terminated with a null.
180 */
181 static void parse(
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182 mike 1.3 const char* text,
183 WQLSelectStatement& statement);
184
185 /** Version of parse() taking an array of characters.
186 */
187 static void parse(
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188 david.dillard 1.8 const Array<char>& text,
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189 mike 1.3 WQLSelectStatement& statement);
190
191 /** Version of parse() taking a string.
192 */
193 static void parse(
194 const String& text,
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195 mike 1.2 WQLSelectStatement& statement);
196
197 private:
198
199 /** This method cleans up all the strings which were created by LEX and
200 passed to YACC. These strings cannot be cleaned up by YACC actions
201 since the actions that clean up certain strings are not always reached
202 when errors occur.
203 */
204 static void cleanup();
205
206 /** Private constructor to avoid user from creating instance of this class.
207 */
208 WQLParser() { }
209 };
210
211 PEGASUS_NAMESPACE_END
212
213 #endif /* Pegasus_WQLParser_h */
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