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version 1.1, 2001/12/02 20:36:49

version 1.1.2.5, 2001/12/12 17:45:53

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//%/////////////////////////////////////////////////////////////////////////////

// The Open Group, Tivoli Systems

// Permission is hereby granted, free of charge, to any person obtaining a copy

// of this software and associated documentation files (the "Software"), to

// deal in the Software without restriction, including without limitation the

// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or

// sell copies of the Software, and to permit persons to whom the Software is

// furnished to do so, subject to the following conditions:

// THE ABOVE COPYRIGHT NOTICE AND THIS PERMISSION NOTICE SHALL BE INCLUDED IN

// ALL COPIES OR SUBSTANTIAL PORTIONS OF THE SOFTWARE. THE SOFTWARE IS PROVIDED

// "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT

// LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR

// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT

// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN

// ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION

// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

//==============================================================================

// Author: Mike Brasher (mbrasher@bmc.com)

// Modified By:

//%/////////////////////////////////////////////////////////////////////////////

#ifndef Pegasus_WQLSelectStatement_h

#define Pegasus_WQLSelectStatement_h

#include <Pegasus/Common/Config.h>

#include <Pegasus/Common/Array.h>

#include <Pegasus/Common/String.h>

#include <Pegasus/WQL/WQLOperation.h>

#include <Pegasus/WQL/WQLOperand.h>

#include <Pegasus/WQL/WQLPropertySource.h>

PEGASUS_NAMESPACE_BEGIN

/** This class represents a compiled WQL1 select statement.

An instance of WQLSelectStatement is passed to WQLParser::parse() which

parses the WQL1 SELECT statement and initializes the WQLSelectStatement

instance. A WQL1 SELECT statement has the following form:

<pre>

SELECT <property>...

FROM <class name>

WHERE <where clause>

</pre>

There are methods for obtaining the various elements of the select

statement.

The components of the where clause are stored in two arrays: one for

operands and one for operators (these are placed in proper order by the

YACC parser). Evaluation is performed using a Boolean stack. See the

implementation of evaluateWhereClause() for details.

class PEGASUS_WQL_LINKAGE WQLSelectStatement

{

public:

/** Default constructor.

WQLSelectStatement();

/** Destructor.

~WQLSelectStatement();

/** Clears all data members of this object.

void clear();

/** Accessor.

const String& getClassName() const

{

return _className;

}

/** Modifier. This method should not be called by the user (only by the

parser).

void setClassName(const String& className)

{

_className = className;

}

/** Returns the number of property names which were indicated in the

selection list.

Uint32 getSelectPropertyNameCount() const

{

return _selectPropertyNames.size();

}

/** Gets the i-th selected property name in the list.

const String& getSelectPropertyName(Uint32 i)

{

return _selectPropertyNames[i];

}

/** Appends a property name to the property name list. This user should

not call this method; it should only be called by the parser.

void appendSelectPropertyName(const String& x)

{

_selectPropertyNames.append(x);

}

/** Returns the number of unique property names from the where clause.

Uint32 getWherePropertyNameCount() const

{

return _wherePropertyNames.size();

}

/** Gets the i-th unique property appearing in the where clause.

const String& getWherePropertyName(Uint32 i)

{

return _wherePropertyNames[i];

}

/** Appends a property name to the where property name list. This user

should not call this method; it should only be called by the parser.

@param x name of the property.

@return false if a property with that name already exists.

Boolean appendWherePropertyName(const String& x);

/** Appends an operation to the operation array. This method should only

be called by the parser itself.

void appendOperation(WQLOperation x)

{

_operations.append(x);

}

/** Appends an operand to the operation array. This method should only

be called by the parser itself.

void appendOperand(const WQLOperand& x)

{

_operands.append(x);

}

/** Returns true if this class has a where clause.

Boolean hasWhereClause() const

{

return _operations.size() != 0;

}

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

Boolean evaluateWhereClause(const WQLPropertySource* source) const;

/** Prints out the members of this class.

void print() const;

private:

// The name of the target class. For example:

// SELECT *

// FROM TargetClass

// WHERE ...

String _className;

// The list of property names being selected. For example, see "firstName",

// and "lastName" below.

// SELECT firstName, lastName

// FROM TargetClass

// WHERE ...

Array<String> _selectPropertyNames;

// The unique list of property names appearing in the WHERE clause.

// Although a property may occur many times in the WHERE clause, it will

// only appear once in this list.

Array<String> _wherePropertyNames;

// The list of operations encountered while parsing the WHERE clause.

// Consider this query:

// SELECT *

// FROM TargetClass

// WHERE count > 10 OR peak < 20 AND state = "OKAY"

// This would generate the following stream of WQLOperations:

// WQL_GT

// WQL_LT

// WQL_EQ

// WQL_AND

// WQL_OR

Array<WQLOperation> _operations;

// The list of operands encountered while parsing the WHERE clause. They

// query just above would generate the following stream of operands:

// count, 10, peak, 20, state, "OKAY"

Array<WQLOperand> _operands;

void f() const { }

};

PEGASUS_NAMESPACE_END

#endif /* Pegasus_WQLSelectStatement_h */

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