OperandExpression Class Reference

Represents base clase of all XQuery operands of a condition. More...

#include <operandexpression.h>

Inheritance diagram for OperandExpression:

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Collaboration diagram for OperandExpression:

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List of all members.

Public Member Functions
	OperandExpression (EXP_TYPE _type, EXP_TYPE _op_type)
	Constructor.
virtual	~OperandExpression ()
virtual bool	isSingleValued ()=0
	Returns if the result/iteration of the operand is a single value.
virtual void	prepareOperand (OutputStream &eos, Environment *env, unsigned modus)=0
	Initializes the operand if necessary.
virtual void	unprepareOperand ()=0
	Resets the operand if necessary.
virtual Value *	getNextValue ()=0
	Returns the next value of the operand.
const EXP_TYPE	getOperandType ()
	Returns the type of the operand.
Protected Attributes
EXP_TYPE	op_type
	The entered EXP_TYPE.
bool	initial
Value	cur_val

---

Detailed Description

Represents base clase of all XQuery operands of a condition.

Represents base clase of all XQuery operands of a condition, i.e. represents a operand of a CondOperandExpression, which takes either a VarExpression, e.g. $x, $z or $root, a VarStepExpression, e.g. $x/bib//book or //node()/text(), a AggregateFunctExpression, e.g. fn:count($x) or fn:sum(/bib//book), a RoundingExpression, e.g. fn:avg(fn:sum(/bib//book)) or fn:round(fn:avg(/bib//book)), or a ConstExpression, e.g. "foo" or 8, as argument and returns the evaluated value of the corresponding Expression.

Author:

Michael Schmidt

Gunnar Jehl

Version:

2.1

License:

Software License Agreement (BSD License)

Definition at line 54 of file operandexpression.h.

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Constructor & Destructor Documentation

OperandExpression::OperandExpression	(	EXP_TYPE	_type,
		EXP_TYPE	_op_type
	)

Constructor.

Constructor - creating object for two EXP_TYPE.

Parameters:

[in]	_type	EXP_TYPE.
[in]	_op_type	EXP_TYPE.

Definition at line 37 of file operandexpression.cpp.

OperandExpression::~OperandExpression

(

)

[virtual]

Destructor.

Definition at line 43 of file operandexpression.cpp.

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Member Function Documentation

Value * OperandExpression::getNextValue

(

)

[pure virtual]

Returns the next value of the operand.

Returns the next value of the operand for iteration.

Return values:

Value*

Pointer to a Value object.

Implemented in AggregateFunctExpression, ConstExpression, NumericConstExpression, RoundingExpression, StringConstExpression, VarExpression, and VarStepExpression.

Referenced by CondOperandExpression::evalCond().

const EXP_TYPE OperandExpression::getOperandType

(

)

[inline]

Returns the type of the operand.

Returns the type of the operand.

Return values:

const

EXP_TYPE EXP_TYPE.

Definition at line 108 of file operandexpression.h.

References op_type.

bool OperandExpression::isSingleValued

(

)

[pure virtual]

Returns if the result/iteration of the operand is a single value.

Returns if the result/iteration of the operand is a single value, e.g a AggregateFunctExpression returns a single value whereas a VarStepExpression may return more than one value.

Return values:

bool

if the result/iteration is a single value, false otherwise.

Implemented in AggregateFunctExpression, ConstExpression, RoundingExpression, VarExpression, and VarStepExpression.

Referenced by CondOperandExpression::evalCond().

void OperandExpression::prepareOperand	(	OutputStream &	eos,
		Environment *	env,
		unsigned	modus
	)			[pure virtual]

Initializes the operand if necessary.

Initializes the operand if necessary.

Parameters:

[in]	eos	Pointer to a OutputStream object.
[in]	env	Pointer to a Environment object.
[in]	modus	Evaluation modus.

Return values:

void

Implemented in AggregateFunctExpression, ConstExpression, RoundingExpression, VarExpression, and VarStepExpression.

Referenced by CondOperandExpression::evalCond().

void OperandExpression::unprepareOperand

(

)

[pure virtual]

Resets the operand if necessary.

Resets the operand if necessary.

Return values:

void

Implemented in AggregateFunctExpression, ConstExpression, RoundingExpression, VarExpression, and VarStepExpression.

Referenced by CondOperandExpression::evalCond().

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Member Data Documentation

Value OperandExpression::cur_val [protected]

Container for the result of the operand.

Definition at line 127 of file operandexpression.h.

Referenced by FunctTruncateExpression::eval(), FunctRoundHalfToEvenExpression::eval(), FunctRoundExpression::eval(), FunctFloorExpression::eval(), FunctCoverExpression::eval(), FunctCeilingExpression::eval(), FunctAbsExpression::eval(), AggregateFunctVarSampExpression::eval(), AggregateFunctVarPopExpression::eval(), AggregateFunctSumExpression::eval(), AggregateFunctStdDevSampExpression::eval(), AggregateFunctStdDevPopExpression::eval(), AggregateFunctMinExpression::eval(), AggregateFunctMedianExpression::eval(), AggregateFunctMaxExpression::eval(), AggregateFunctCountExpression::eval(), AggregateFunctAvgExpression::eval(), VarStepExpression::getNextValue(), VarExpression::getNextValue(), StringConstExpression::getNextValue(), RoundingExpression::getNextValue(), NumericConstExpression::getNextValue(), and AggregateFunctExpression::getNextValue().

bool OperandExpression::initial [protected]

Indicator for method getNextValue() if first call/iteration.

Definition at line 121 of file operandexpression.h.

Referenced by StringConstExpression::getNextValue(), RoundingExpression::getNextValue(), NumericConstExpression::getNextValue(), AggregateFunctExpression::getNextValue(), RoundingExpression::unprepareOperand(), ConstExpression::unprepareOperand(), and AggregateFunctExpression::unprepareOperand().

EXP_TYPE OperandExpression::op_type [protected]

The entered EXP_TYPE.

The entered EXP_TYPE, which is the second argument of the constructor.

Definition at line 115 of file operandexpression.h.

Referenced by getOperandType().