1 mike  1.1.2.1 //%/////////////////////////////////////////////////////////////////////////////
  2               //
  3               // Copyright (c) 2000, 2001 BMC Software, Hewlett-Packard Company, IBM, 
  4               // The Open Group, Tivoli Systems
  5               //
  6               // Permission is hereby granted, free of charge, to any person obtaining a copy
  7               // of this software and associated documentation files (the "Software"), to 
  8               // deal in the Software without restriction, including without limitation the 
  9               // rights to use, copy, modify, merge, publish, distribute, sublicense, and/or 
 10               // sell copies of the Software, and to permit persons to whom the Software is
 11               // furnished to do so, subject to the following conditions:
 12               // 
 13               // THE ABOVE COPYRIGHT NOTICE AND THIS PERMISSION NOTICE SHALL BE INCLUDED IN 
 14               // ALL COPIES OR SUBSTANTIAL PORTIONS OF THE SOFTWARE. THE SOFTWARE IS PROVIDED
 15               // "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT
 16               // LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR 
 17               // PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT 
 18               // HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN 
 19               // ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 20               // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 21               //
 22 mike  1.1.2.1 //==============================================================================
 23               //
 24               // Author: Mike Brasher (mbrasher@bmc.com)
 25               //
 26               // Modified By:
 27               //
 28               //%/////////////////////////////////////////////////////////////////////////////
 29               
 30               #ifndef Pegasus_WQLSelectStatement_h
 31               #define Pegasus_WQLSelectStatement_h
 32               
 33               #include <Pegasus/Common/Config.h>
 34               #include <Pegasus/Common/Array.h>
 35               #include <Pegasus/Common/String.h>
 36               #include <Pegasus/WQL/WQLOperation.h>
 37               #include <Pegasus/WQL/WQLOperand.h>

 38 mike  1.1.2.2 #include <Pegasus/WQL/WQLPropertySource.h>

 39 mike  1.1.2.1 
 40               PEGASUS_NAMESPACE_BEGIN
 41               

 42 mike  1.1.2.4 /** This class represents a compiled WQL1 select statement. 

 43 mike  1.1.2.1 
 44                   An instance of WQLSelectStatement is passed to WQLParser::parse() which

 45 mike  1.1.2.4     parses the WQL1 SELECT statement and initializes the WQLSelectStatement
 46                   instance. A WQL1 SELECT statement has the following form:

 47 mike  1.1.2.1 
 48                   <pre>

 49 mike  1.1.2.4 	SELECT <property>...
 50               	FROM <class name>
 51               	WHERE <where clause>

 52 mike  1.1.2.1     </pre>
 53               

 54 mike  1.1.2.4     The properties are obtained with the getProperties() method. The class 
 55                   name is obtained with getClassName(). The where clause is evaluated by 
 56                   calling evaluateWhereClause() with the appropriate arguments. If 
 57                   hasWhereClause() returns false, then there is no where clause.

 58 mike  1.1.2.1 
 59                   The components of the where clause are stored in two arrays: one for
 60                   operands and one for operators (these are placed in proper order by the
 61                   YACC parser). Evaluation is performed using a Boolean stack. See the
 62                   implementation of evaluateWhereClause() for details.
 63               */
 64               class PEGASUS_WQL_LINKAGE WQLSelectStatement
 65               {
 66               public:
 67               
 68                   /** Default constructor. 
 69                   */
 70                   WQLSelectStatement();
 71               
 72                   /** Destructor.
 73                   */
 74                   ~WQLSelectStatement();
 75               
 76                   /** Clears all data members of this object.
 77                   */
 78                   void clear();
 79 mike  1.1.2.1 
 80                   /** Accessor.
 81                   */
 82                   const String& getClassName() const
 83                   {
 84               	return _className;
 85                   }
 86               
 87                   /** Modifier. This method should not be called by the user (only by the
 88               	parser).
 89                   */
 90                   void setClassName(const String& className)
 91                   {
 92               	_className = className;
 93                   }
 94               
 95                   /** Returns the number of property names which were indicated in the
 96               	selection list.
 97                   */
 98                   Uint32 getPropertyNameCount() const
 99                   {
100 mike  1.1.2.1 	return _propertyNames.size();
101                   }
102               
103                   /** Gets the i-th property name in the list.
104                   */
105                   const String& getPropertyName(Uint32 i)
106                   {
107               	return _propertyNames[i];
108                   }
109               
110                   /** Appends a property name to the property name list. This user should
111               	not call this method; it should only be called by the parser.
112                   */
113                   void appendPropertyName(const String& x)
114                   {
115               	_propertyNames.append(x);
116                   }
117               
118                   /** Appends an operation to the operation array. This method should only
119               	be called by the parser itself.
120                   */
121 mike  1.1.2.1     void appendOperation(WQLOperation x)
122                   {
123               	_operations.append(x);
124                   }
125               
126                   /** Appends an operand to the operation array. This method should only
127               	be called by the parser itself.
128                   */
129                   void appendOperand(const WQLOperand& x)
130                   {
131               	_operands.append(x);
132                   }
133               
134                   /** Returns true if this class has a where clause.
135                   */
136                   Boolean hasWhereClause() const
137                   {
138               	return _operations.size() != 0;
139                   }
140               

141 mike  1.1.2.2     /** Evalautes the where clause using the symbol table to resolve symbols.

142 mike  1.1.2.1     */

143 mike  1.1.2.3     Boolean evaluateWhereClause(const WQLPropertySource* source) const;

144 mike  1.1.2.1 
145                   /** Prints out the members of this class.
146                   */
147                   void print() const;
148               
149               private:
150               
151                   //
152                   // The name of the target class. For example:
153                   //
154                   //     SELECT * 
155                   //     FROM TargetClass
156                   //     WHERE ...
157                   //
158               
159                   String _className;
160               
161                   //
162                   // The list of property names being selected. For example, see "firstName",
163                   // and "lastName" below.
164                   //
165 mike  1.1.2.1     //     SELECT firstName, lastName 
166                   //     FROM TargetClass
167                   //     WHERE ...
168                   //
169               
170                   Array<String> _propertyNames;
171               
172                   //
173                   // The list of operations encountered while parsing the WHERE clause.
174                   // Consider this query:
175                   //
176                   //     SELECT *
177                   //     FROM TargetClass
178                   //     WHERE count > 10 OR peak < 20 AND state = "OKAY"
179                   //
180                   // This would generate the following stream of WQLOperations:
181                   //
182                   //     WQL_GT
183                   //     WQL_LT
184                   //     WQL_EQ
185                   //     WQL_AND
186 mike  1.1.2.1     //     WQL_OR
187                   //
188               
189                   Array<WQLOperation> _operations;
190               
191                   // 
192                   // The list of operands encountered while parsing the WHERE clause. They
193                   // query just above would generate the following stream of operands:
194                   //
195                   //     count, 10, peak, 20, state, "OKAY"
196                   //
197               
198                   Array<WQLOperand> _operands;
199               };
200               
201               PEGASUS_NAMESPACE_END
202               
203               #endif /* Pegasus_WQLSelectStatement_h */