1 chuck 1.2 //%2003////////////////////////////////////////////////////////////////////////
  2           //
  3           // 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.;
  6           // IBM Corp.; EMC Corporation, The Open Group.
  7           //
  8           // Permission is hereby granted, free of charge, to any person obtaining a copy
  9           // of this software and associated documentation files (the "Software"), to
 10           // deal in the Software without restriction, including without limitation the
 11           // rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 12           // sell copies of the Software, and to permit persons to whom the Software is
 13           // furnished to do so, subject to the following conditions:
 14           // 
 15           // THE ABOVE COPYRIGHT NOTICE AND THIS PERMISSION NOTICE SHALL BE INCLUDED IN
 16           // ALL COPIES OR SUBSTANTIAL PORTIONS OF THE SOFTWARE. THE SOFTWARE IS PROVIDED
 17           // "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT
 18           // LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
 19           // PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 20           // HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 21           // ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 22 chuck 1.2 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 23           //
 24           //==============================================================================
 25           //
 26           // Author: Humberto Rivero (hurivero@us.ibm.com)
 27           //
 28           // Modified By:
 29           //
 30           //%/////////////////////////////////////////////////////////////////////////////
 31           
 32           #ifndef Pegasus_CQLParser_h
 33           #define Pegasus_CQLParser_h
 34           
 35           #include <Pegasus/Common/Config.h>
 36           #include <Pegasus/Common/ArrayInternal.h>
 37           #include <Pegasus/CQL/Linkage.h>
 38           #include <Pegasus/CQL/CQLSelectStatement.h>
 39           
 40           #ifdef PEGASUS_USE_EXPERIMENTAL_INTERFACES
 41           
 42           PEGASUS_NAMESPACE_BEGIN
 43 chuck 1.2 
 44           /** This class is the main interface to the CQL parser used for parsing CQL1
 45               compliant SQL statements.
 46           
 47               Here's an example which parses a SELECT statement:
 48           
 49               <pre>
 50           	const char TEXT[] = "SELECT X,Y FROM MyClass WHERE X > 10 AND Y < 3";
 51           
 52           	// Note that this array must be null-terminated (sizeof(TEXT) includes
 53           	// the null-terminator in the count).
 54           
 55           	Array<Sint8> text(TEXT, sizeof(TEXT));
 56           
 57           	WQLSelectStatement selectStatement;
 58           
 59           	WQLParser parser;
 60           
 61           	try
 62           	{
 63           	    parser.parse(text, selectStatement);
 64 chuck 1.2 	}
 65           	catch (ParseError&)
 66           	{
 67           	    ...
 68           	}
 69           	catch (MissingNullTerminator&)
 70           	{
 71           	    ...
 72           	}
 73               </pre>
 74           
 75               Note that the text must be NULL terminated or else the MissingNullTerminator
 76               exception is thrown.
 77           
 78               The text is read and the result is left in the selectStatement output
 79               argument.
 80           
 81               At this point you might wish to peek at the contents of the selectStatement.
 82               This may be done by calling WQLSelectStatement::print() like this:
 83           
 84               <pre>
 85 chuck 1.2 	WQLSelectStatement selectStatement;
 86           	...
 87           	selectStatement.print();
 88               </pre>
 89           
 90               For the above query text, the following is printed:
 91           
 92               <pre>
 93           	WQLSelectStatement
 94           	{
 95           	    _className: "MyClass"
 96           
 97           	    _propertyNames[0]: "X"
 98           	    _propertyNames[1]: "Y"
 99           
100           	    _operations[0]: "WQL_GT"
101           	    _operations[1]: "WQL_LT"
102           	    _operations[2]: "WQL_AND"
103           
104           	    _operands[0]: "PROPERTY_NAME: X"
105           	    _operands[1]: "INTEGER_VALUE: 10"
106 chuck 1.2 	    _operands[2]: "PROPERTY_NAME: Y"
107           	    _operands[3]: "INTEGER_VALUE: 3"
108           	}
109               </pre>
110           
111               The WQLSelectStatement::evaluateWhereClause() method may be called to
112               determine whether a particular instance (whose properties are made 
113               available to he evaluateWhereClause() by a user implementation of the
114               WQLPropertySource class). This method returns true, if the where clause
115               matches this instance. Here is an example:
116           
117               <pre>
118           	WQLSelectStatement selectStatement;
119           	...
120           	WQLPropertySource* propertySource = new MyPropertySource(...);
121           
122           	if (selectStatement.evaluateWhereClause(propertySource))
123           	{
124           	    // It's a match!
125           	}
126               </pre>
127 chuck 1.2 
128               The evaluateWhereClause() method calls propertySource->getValue() to
129               obtain values for each of the properties referred to in where clause (X 
130               and Y in the above query example).
131           
132               The implementer of the WQLPropertySource interface must provide the
133               implementation of getValue() to produce values for the target data
134               types. The WQL library makes no assumptions about the nature of the 
135               target data representation. This was done so that this libary could be
136               adapted to multiple data representations.
137           
138               For use with Pegasus CIMInstance objects, a CIMInstancePropertySource
139               class could be developed whose getValue() method fetches values from 
140               a CIMInstance. Here is an example of how it might be used.
141           
142               <pre>
143           	CIMInstancePropertySource* propertySource 
144           	    = new CIMInstancePropertySource(...);
145           
146           	CIMInstance instance;
147           
148 chuck 1.2 	while (instance = GetNextInstance(...))
149           	{
150           	    propertySource->setInstance(currentInstance);
151           
152           	    if (selectStatement.evaluateWhereClause(propertySource))
153           	    {
154           		// It's a match!
155           	    }
156           	}
157               </pre>
158           
159               Of course the numeration of instances is left to the user of WQL.
160           */
161           class PEGASUS_CQL_LINKAGE CQLParser
162           {
163           public:
164           
165               /** Parse the SELECT statement given by the text parameter and initialize
166           	the statement parameter accordingly.
167           
168           	Please note that this method is not thread safe. It must be guarded 
169 chuck 1.2 	with mutexes by the caller.
170           
171           	@param text null-terminated C-string which points to SQL statement.
172           	@param statement object which holds the compiled version of the SELECT
173           	    statement upon return.
174           	@exception ParseError if text is not a valid SELECT statement.
175           	@exception MissingNullTerminator if text argument is not 
176           	    terminated with a null. 
177               */
178               static void parse(
179           	const char* text,
180           	CQLSelectStatement& statement);
181           
182               /** Version of parse() taking an array of characters.
183               */
184               static void parse(
185           	const Array<Sint8>& text,
186           	CQLSelectStatement& statement);
187           
188               /** Version of parse() taking a string.
189               */
190 chuck 1.2     static void parse(
191           	const String& text,
192           	CQLSelectStatement& statement);
193           
194           private:
195           
196               /** This method cleans up all the strings which were created by LEX and
197           	passed to YACC. These strings cannot be cleaned up by YACC actions
198           	since the actions that clean up certain strings are not always reached
199           	when errors occur.
200               */
201               static void cleanup();
202           
203               /** Private constructor to avoid user from creating instance of this class.
204               */
205               CQLParser() { }
206           };
207           
208           PEGASUS_NAMESPACE_END
209           #endif
210           #endif /* Pegasus_WQLParser_h */